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Research article 07 Jun 2021
Research article | 07 Jun 2021
Quality assessment of Dobson spectrophotometers for ozone column measurements before and after automation at Arosa and Davos
Quality assessment of Dobson spectrophotometers for ozone column measurements before and after automation at Arosa and Davos Quality assessment of Dobson spectrophotometers for ozone column measurements before and after... René Stübi et al.
René Stübi1, Herbert Schill2, Eliane Maillard Barras1, Jörg Klausen1, and Alexander Haefele1 René Stübi et al. René Stübi1, Herbert Schill2, Eliane Maillard Barras1, Jörg Klausen1, and Alexander Haefele1
1Federal Office of Meteorology and Climatology, MeteoSwiss, 1530 Payerne, Switzerland
2Physikalisch-Meteorologisches Observatorium Davos/World Radiation Center, 7260 Davos, Switzerland
Correspondence: René Stübi (rene.stubi@meteoswiss.ch)
Received: 06 Nov 2020 – Discussion started: 04 Dec 2020 – Revised: 08 Apr 2021 – Accepted: 21 Apr 2021 – Published: 07 Jun 2021
The longest ozone column measurement series are based on the Dobson sun spectrophotometers developed in the 1920s by Gordon B. W. Dobson. These instruments still constitute an important part of the World Meteorological Organization's global network due to their optical qualities and ruggedness. The primary drawback of this instrument is the effort needed for its manual operation. In industrialized and some less developed countries, most stations have made the choice to replace the Dobson by the automated Brewer sun spectrophotometers, but some are still relying on the Dobson instrument. One of them is the Arosa station where both instrument types are run in parallel. Here, an automated version of the Dobson instrument was developed and implemented recently. In the present paper, the results of the analysis of simultaneous measurements from pairs of Dobson instruments that were either collocated at Arosa or Davos or operated one at each location are presented for four distinct time periods:
1992–2012 – manual vs. manual operation of collocated Dobson instruments (MMC);
2012–2013 – manual vs. automated operation of collocated Dobson instruments (MAC);
2012–2019 – automated vs. automated operation of collocated Dobson instruments (AAC);
2016–2019 – automated vs. automated operation of distant Dobson instruments (AAD).
The direct comparison of two instruments using the standard operation procedure during the MMC period gives a metric necessary to validate the automated version of Dobson instruments. The direct comparison of two collocated instruments using the standard manual operation procedure reveals random differences of coincident observations with a standard deviation of ∼ 0.45 % and monthly mean differences between −1.0 % and +0.8 %. In most cases the observed biases are not statistically significant. The same analysis of two automated Dobson instruments yields significantly smaller standard deviation of ∼ 0.25 % and biases of between −0.7 % and 0.8 %. This demonstrates that the repeatability has improved with the automation, while the systematic differences are only marginally smaller. The analysis of the AAD period of coincident measurements from the distant sites Arosa and Davos reveals a small positive bias (not significant) compatible with the 250 m altitude difference.
The description of the automated data acquisition and control of the Dobson instrument is presented in a separate paper (Stübi et al., 2020).
Article (PDF, 2497 KB)
Stübi, R., Schill, H., Maillard Barras, E., Klausen, J., and Haefele, A.: Quality assessment of Dobson spectrophotometers for ozone column measurements before and after automation at Arosa and Davos, Atmos. Meas. Tech., 14, 4203–4217, https://doi.org/10.5194/amt-14-4203-2021, 2021.
In 2017, the celebration of 30 years of the Montreal Protocol (Albrecht and Parker, 2019) was a reminder of this important worldwide agreement to ban the use and the production of substances harmful for the ozone layer in industrial processes as well as their release to the atmosphere (Solomon, 1999). Present monitoring activities show the effectiveness of the protocol in the stabilization and the decrease in their abundance in the atmosphere. However, while ozone layer depletion seems to have stopped since the beginning of the 21st century, the expected recovery of the ozone layer to the pre-1980 level has still not been observed in most parts of the atmosphere. Hence it remains important to continue with the monitoring at the global scale. The anxiety about the ozone hole has favored the development of well organized dedicated monitoring networks based in particular on the Dobson and Brewer instruments. In these networks, the Light Climatic Observatory (LKO for German "Licht Klimatisches Observatorium") at Arosa has a special renown since it provides the longest continuous total ozone column measurement series whose first measurements date back to 1926 as illustrated in Fig. 1. While the ozone column decline of the 1970s–1980s is clearly seen, followed by a leveling off since the mid-1990s, the expected recovery of the ozone layer is not evident up to now, neither in the LKO total column ozone time series nor at other ground-based stations (Ball et al., 2019). The trend analysis of the ozone abundance at different altitude ranges is still the subject of research and publications (e.g., Pawson et al., 2014; WMO, 2018; SPARC/IO3C/GAW, 2019). A clear sign of recovery is presently observed at mid-latitude in the upper stratosphere (∼ 40 km), driven by chemical changes in accordance with numerical models forecast. This is interpreted as a positive consequence of the Montreal Protocol. In contrast, another publication (Ball et al., 2018) still revealed a negative ozone trend in the lower stratosphere (∼ 10 km) probably linked to dynamical changes or atmospheric variability and reminded the public that the rhetoric of the ozone problem being already solved was overly optimistic.
Figure 1Arosa ozone column time series: yearly mean values in Dobson Units [DU]. The shaded area depicts the standard deviation of the monthly means of each year.
The history of the LKO and the essential role of ozone pioneers in keeping a measurement site active over such a long period of time was detailed in two publications (Staehelin et al., 2018; Staehelin and Viatte, 2019). The link between the LKO activities and societal concerns was highlighted in particular with the tuberculosis treatment in the earlier years and the ozone hole more recently. The LKO ozone column measurement series and the succession of instruments in operation has been analyzed before (Perl and Dütsch, 1958; Dütsch, 1984; Brönnimann et al., 2003). Staehelin et al. (1998) described 4 decades of use of Dobson D015 at Arosa from 1948 until 1992 and the arrival of Dobson D101 in 1966 as a redundant instrument. With the decommissioning of D015 in 1992, D101 became the reference instrument, and the newly arrived Dobson D062 took the role of the redundant instrument. The instruments were upgraded with a digital recording of the R-dial position at the end of the 1980s (Hoegger et al., 1992) but continued to be manually operated in a dedicated convenient-to-use rotating cabin.
Dütsch, the responsible scientist for LKO, made first attempts to automate the Dobson instrument in the 1970s (Räber, 1973). For technical reasons, the project was suspended for the direct sun measurements but was continued for the zenith measurements. The latter do not require precise sun pointing and are used to determine the ozone profile with altitude at low solar zenith angle (Umkehr method, Petropavlovskikh et al., 2009). The implementation of a fully automated version of the Dobson instrument developed at MeteoSwiss between 2012 and 2014 motivated the new analysis of the data as presented here. More technical aspects of the automation are described in a separate paper (Stübi et al., 2020). The automated Dobson instruments require only occasional presence on-site essentially for lamps tests. Following this transition to automated operation, the comparison of the two sites Arosa and Davos started, with a view to continue the world's longest total column ozone series based on Dobson observations in Davos. Principles for climate monitoring systems have been adopted by the World Meteorological Organization (WMO). Known as the Global Climate Observing System (GCOS) principles, they assure the continuity of the Essential Climate Variable (ECV) records like the Arosa total ozone series. GCOS principle 1 requires that "The impact of new systems or changes to existing systems should be assessed prior to implementation" and GCOS principle 2 that "A suitable period of overlap for new and old observing systems is required". The present analysis is a response to the GCOS principles for the change of Dobson measuring technique (manual to automated) followed by a change of instrument location (Arosa to Davos). The adherence to these principles assures the continuity of the Arosa series with measurements at Davos and the homogeneity of the combined record.
The present study is centered on the analysis of Dobson instruments data and is a follow-up of two previous analyses of the LKO Brewer triad measurements (Stübi et al., 2017a, b).
The paper is organized as follows: in Sect. 2, the measurement principles are presented, followed in Sect. 3 by a description of the data sets and of the data quality control procedures applied. The results of the analysis are presented in Sect. 4 and the discussion of the results in Sect. 5.
2 Dobson spectrophotometer measurements
The principle of the Dobson instrument is described in many publications (Dobson, 1968; Komhyr, 1980; Evans, 2008; Scarnato et al., 2009, 2010; Moeini et al., 2019). The intensity of the sun's radiation in the UV range at ground level is modulated by the amount of ozone in the atmosphere. The sun spectrophotometers of type Dobson and Brewer measure the intensity at a few specific wavelengths in the range 305–340 nm. In the Dobson instrument, the sunlight is diffracted by a prism and two narrow slits allow to select the different pairs of wavelength commonly referred to as A (305.5/325.4 nm), C (311.45/332.4 nm) and D (317.6/339.8 nm). These pairs are combined to form the double pairs AD and CD used to calculate the ozone column while eliminating atmospheric interferences (Evans, 2008; Basher, 1982). Following Evans (2008) notation, the ozone column is retrieved with the following formula:
(1) O 3 = X AD = N A - N D - β s - β l A - β s - β l D m p p 0 - δ s - δ l A - δ s - δ l D sec ( SZA ) α s - α l A - α s - α l D μ ,
where the superscripts s (l) refer to the short (long) wavelength within each pair, αλ is the absorption coefficient of ozone, βλ and δλ are respectively the Rayleigh and Mie scattering coefficients, and m and μ refer to the air masses for Rayleigh and ozone respectively. The ratio p/p0 is a correction for the mean station pressure, and SZA is the solar zenith angle. The measured N values are the logarithmic differences of the solar radiation intensity ratios I0s/I0l at the top of the atmosphere and Is/Il at the surface:
(2) N A - N D = log I 0 s I 0 l - log I s I l A - log I 0 s I 0 l - log I s I l D .
The wavelength dependence of the Mie scattering is much smaller than the dependence of ozone and Raleigh scatterings; therefore, the last term of Eq. (1) is negligible for the double pairs. In the Brewer instruments, a diffraction grating selects four wavelengths (310.1, 313.5, 316.8, 320.0 nm), which are then combined in a similar way as for the Dobson instrument to extract the ozone column (Kerr et al., 1981; Kerr and McElroy, 1995). All Dobson instruments are of the same design, and the optical alignment of the prisms, lenses and the slits is standardized for all instruments. Consequently, the Dobson ozone column retrieval algorithm is fairly simple and assumes similar characteristics for all instruments – characteristics based on the optical properties of the primary reference Dobson instrument D083 (Komhyr et al., 1989). In the past 10 years, the EMRP-ATMOZ project has contributed to an improved understanding of the sun spectrophotometer's measurement principle (ATMOZ Project, 2018). Thus, measurements of the Dobson slit functions (Köhler et al., 2018), of the ozone cross sections and their temperature dependencies (Bass and Paur, 1985; Serdyuchenko et al., 2014; Malicet et al., 1995; Janssen et al., 2018), of the stray-light effect (Christodoulakis et al., 2015; Karppinen et al., 2015; Moeini et al., 2019), and their implications on the ozone column retrieval for different instruments (Redondas et al., 2014) are now available. An adaptation of the processing algorithm with these recent findings would certainly improve the absolute accuracy of future ozone observations. However, it is harder to apply these findings consistently to the historical records of Dobson measurements because some essential instrument characteristics (slit functions, wavelengths in use, etc.) are not available for older instruments and data sets.
The Dobson network calibration is organized by the World Meteorological Organization's (WMO) Global Atmosphere Watch program. It consists of the World Dobson Calibration Center (WDCC; with one primary standard Dobson and one traveling primary standard Dobson instrument) and five Regional Dobson Calibrations Centers (RDCCs; with six secondary standard Dobson instruments). Calibrations of the primary standard Dobson by the Langley method are regularly performed at the Mauna Loa Observatory, Hawaii. Dobson instrument of the network are calibrated either directly or indirectly relative to the primary standard scale to maintain the homogeneity of the network (Komhyr et al., 1989). For Europe, two regional secondary standard Dobson instruments are in use: D064 from the Hohenpeissenberg Observatory (MOHp, Germany) and D074 from the Solar and Ozone Observatory in Hradec Králové (SOO-HK, Czech Republic). These calibrations were carried out regularly at LKO as indicated in Fig. 3 by the black arrows.
The Dobson automation and relocation from LKO to the Physikalisch-Meteorologisches Observatorium Davos/World Radiation Center (PMOD/WRC) was considered by MeteoSwiss with the prospect of perpetuating the measurements in the long term under optimal conditions. Factors considered in the analysis included the availability of operators for a year-round 24/7 monitoring program, data quality improvements (repeatability, reproducibility, increased frequency of measurements) and reduction of operational cost due to institutional synergies. Great care was taken to avoid a fundamental change of the Dobson measurements and hence to support the continuity of the LKO ozone column time series.
Table 1Chronology of the interventions and calibrations of the three Dobson instruments over the transition period 2010–2015 from manual to automated Dobson operation.
A description of the technical details of the automated system is found in a separate publication (Stübi et al., 2020). Table 1 lists the dates of the main changes that have the potential to introduce changes in the measurements of the three LKO Dobson instruments. By the end of 2015, all three Dobson instruments were automated and had reached the same configuration.
3 Data sets of coincident measurements
The automation of the Dobson spectrophotometers D062 and D051 was performed between the intercomparisons of summer 2010 and summer 2012, while D101 was automated at the beginning of 2014. Until early 2016, the three Dobson instruments were at LKO as illustrated by the red and blue color bars in the upper panel of Fig. 2. Then, Dobson D101 was moved to the PMOD/WRC. Stübi et al. (2017b) have described the stations and have analyzed the similar relocation from Arosa to Davos of Brewer instruments in terms of differing environmental factors with a potential to break the LKO ozone column series.
Figure 2(a) Historical changes of the Dobson operation as well as of the instrument locations. (b–d) Time series 2010–2020 of the lamp corrections δNA–δND for the three LKO Dobson instruments. The vertical yellow bars denote the intercomparisons with the European regional standard. The blue bands mark the unavailability of each Dobson instrument during the process of automation.
The lower three panels of Fig. 2 show the last 10 years of the standard lamps corrections applied for the AD pairs for the three Dobson instruments. A variation of the difference δNA-δND of 0.5 corresponds to ≃ 1 % of the ozone column variation at air mass μ=1, decreasing as 1/μ that is ≃ 0.5 % at μ=2. These panels illustrate the stability of the instruments resulting from regular lamp tests and the adjustments from the maintenance and calibration campaigns (yellow lines). Dobson D101 drifted slowly between 2010–2018, while D051 and D062 were particularly stable besides the 2011 increase in D062. The weather during the 2017 calibration campaign was not fair enough for a good evaluation of the calibration status of the LKO Dobson instruments. Therefore the 2017 calibration is not taken into account in this study.
Since the Dobson intercomparison in July 2012, D051 (previously dedicated to ozone profile measurements with the Umkehr method) has also been used for total ozone measurements. Regular D051 direct sun measurements began however only in March 2013. Therefore the overlap with the reference instrument D101 lasted only 9 months before D101 went to the workshop for the automation.
For the present analysis, measurements from a pair of Dobson instruments were defined as coincident if the following criteria were met: time difference δt<300 s, air mass difference δμ<0.05 and air mass μ≤4. At LKO, the manual operation was facilitated by having the two instruments side by side on a turntable, which resulted in a systematic time difference δt between 45 and 75 s. For the automated operation, the mean δt is close to 0 s.
Until end of 2011, all manual measurements underwent a data quality control on a daily basis. The individual measurements were flagged based on a visual comparison of all Dobson (AD, CD wavelengths double pairs) and Brewer instruments. The meteorological parameters (e.g., global radiation, sunshine duration and rain) were also considered in this process. This approach involved subjective flagging by an experienced scientist. With the increase in the number of measurements by a factor ∼ 10 following the automation in the course of 2012, a different approach was developed. Since then, each Dobson instrument has been treated separately for the single wavelength pairs C, D, and A and for the double pairs AD and CD. In a first step, the sun duration for 10 min periods is used as additional information, and measurements in periods with less than 4 min of sun are flagged. Then the standard deviation of the 20 s R-dial records (δR) is used as a quality criterion. In the next step, an algorithm based on consecutive elimination of bad or doubtful measurements is applied for flagging. A fourth-order polynomial function of time is calculated as a proxy of the daily variation. Outliers are eliminated (flagged) one by one, with the polynomial function being recalculated after each elimination until all measurements of a day fulfill the wavelength and instrument-dependent empirically determined criteria (e.g., for D062 |poly–O3| <0.8 %, <2.0 % and <1.0 % for respectively the C, D and A pair). The 2 min measurement cycle that was adopted helps to identify these outliers based on the assumption that the total ozone abundance changes slowly over time. Therefore, two consecutive measurements must also agree within a given limit. Once these limits and convergence criteria are established, the flagging is done automatically without human intervention. However the measurements of the different instruments are still compared by visual control in order to detect malfunctions or drifts in an individual Dobson, which would then be flagged manually.
In Fig. 3, the time series 1992–2019 of the differences between coincident measurements from Dobson D062 and D101 is shown. We can observe the generally good agreement between these two sets of independent measurements. The transition period 2011–2014 from manual to automated Dobson operations stands out with larger discrepancies and variability in the differences due to the adaptations of the data acquisition system and of the measuring program. Regular calibration campaigns in conformity with the Dobson network procedures which state a 4–5-year calibration cycle are marked in Fig. 3 by the black arrows.
Figure 3Time series of the differences between individual coincident measurements of the Dobson instruments D062 and D101 over the period 1992–2019. Blue: difference D062 − D101 in Dobson units [DU]. Red: difference D062 − D101 / D101 in percent. Black arrows indicate the calibration and maintenance campaigns.
Different time periods are considered as defined by the type of operation (manual vs. automated) and the location of the instruments (Arosa vs. Davos):
1992–2012 – manual vs. manual operation of collocated Dobson instruments (MMC) at LKO;
2012–2013 – manual vs. automated operation of collocated Dobson instruments (MAC) at LKO;
2013–2019 – automated vs. automated operation of collocated Dobson instruments (AAC) at LKO or Davos;
2016–2019 – automated vs. automated operation of distant Dobson instruments (AAD).
Table 2Median differences of coincident data averaged over the whole data set for the four subperiods. P2.5th and P97.5th are respectively the 2.5th and 97.5th percentiles of the sample, and IPR is the range between them.
Table 2 shows the statistics of the observed differences for these different periods of operation of the Dobson instruments. Since there are three instruments and two locations, different cases for a given period are present in Table 2. In the MMC 20-year period, only D101 and D062 were used for total ozone measurements. The median difference is 0.14 % with a 97.5th–2.5th inter-percentile range (IPR97.5th–2.5th) slightly below 4 %. The two instruments were in very good agreement with no significant difference. Considering an average of 250 sunny days a year in Arosa, the 31 129 data points correspond to six to seven coincident observations per day. On the relatively short MAC transition period, automated D062 and D051 were compared to manual D101. For the pair D101–D062 the results are very similar to the MMC case, but for the pair D101–D051 a non significant bias of ∼ 0.6 % is observed. The AAC comparison period shows an increase in the sample sizes by a factor of ∼ 10 together with a reduced IPR97.5th–2.5th and no significant differences. Finally for the AAD period, an intermediate IPR97.5th–2.5th and a non significant bias ∼ 0.4 % were found.
In Stübi et al. (2017a), an analysis of the daily Brewer data to discern the mid-to-long-term variations of the differences and the short-term random fluctuations of coincident measurements was introduced. This was an alternative method to the one introduced by Fioletov et al. (2005) to study the stability of the Toronto Brewer reference triad. Recently León-Luis et al. (2018) published an analysis of the Izaña Brewer triad using both approaches, and they concluded that results are similar for the two analysis methods. As illustrated in Fig. 4, the analysis of Stübi et al. (2017a) involves fitting one single fourth-order polynomial function of time to both sets of measurements for the day considered. This function simulates the mean behavior of the ozone column during that day. For each instrument two parameters are calculated: first, the bias δ (in [DU]) between the polynomial function and the data subset and, second, the standard deviation σ of the measurements around the fit. The difference of the two δi, Δ12=δ1-δ2, corresponds to the mean bias between the two instruments for that day, and it is positive if values from instrument 1 are larger than those of instrument 2 (see Fig. 4). σi is a measure of the random fluctuations of each instrument, i.e., its repeatability. This approach works best with the numerous daily data available from the automated system, but it can also be applied to the manual operation. The results of the daily analysis for the different periods mentioned above are presented in the next subsections.
Figure 4Illustration of the daily values of coincident D062 and D051 automated Dobson measurements for 27 March 2016. The black line is the polynomial fit, and the dashed lines correspond to the bias δ062 of D062 data (blue) and the bias δ051 of D051 data (orange). The difference, Δ062–051 (red), is the bias between D062 and D051 instruments evaluated from the coincident measurements of that day.
4.1 Period of manual operation 1992–2012 (MMC period)
Figure 5 illustrates the results of the daily analysis applied to the period 1992–2012 for the coincident Dobson D101 and D062 data. In the earlier years of parallel measurements, Dobson D062 was between 0.5 % and 1 % higher than D101, but this bias has gradually decreased, and the two data sets have agreed within ±0.5 % since about the year 2000. We note a shallow seasonal cycle in the difference since 2005. The regular maintenance and calibration campaigns (black lines) did not induce noticeable breaks in the time series of differences. We also observe that the differences during the periods following calibrations are not always zero as expected. This is because each instrument was calibrated independently against the traveling standard, and differences of ±0.5 % are within the uncertainty of the calibration procedure itself and were therefore not compensated for. The repeatability σi is shown separately in the lower panel of Fig. 5. Values between 0.3 % and 0.6 % were observed for both instruments. The MMC sections of Table 3 and of Table 4 respectively summarize the statistics of the parameters Δ and σ resulting from the daily analysis. The mean monthly median differences Δ are not significantly different from zero, and the IPR97.5th–2.5th is 1.7 %. The repeatability around ∼ 0.4 % (0.3 %–0.7 %) for these two manually operated Dobson instruments is similar and probably varied depending on the operator's experience and skill. These numbers are our reference metrics for comparing results of manual and automated observations of the Dobson instruments in the next sections.
Figure 5Daily analysis results: time series of the monthly median of the relative difference Δ062–101=δD062-δD101 (a) and the individual σ (b) between coincident measurements of the Dobson instruments D062 and D101 over the period 1992–2012. Calibration campaigns are denoted by the black lines. The shading and the error bars are for the IPR97.5th–2.5th interval.
Table 3Mean monthly medians of parameters Δ for the four subperiods.
Table 4Mean monthly median of the parameters σi for the four subperiods.
4.2 Period of manual vs. automated Dobson operation (MAC period)
Over the 1.5-year period, while the data acquisition and measurement program for automatic operation were developed, different interventions interrupted and perturbed the measurements repeatedly. Changes in the automated operating procedures, their timing and improvements of hardware components make the comparison between the systems challenging. It was also demanding for the operators to measure continuously to get a sufficiently large data set of coincident measurements between the manual and automated instruments. During the Dobson intercomparison campaign in July 2012, D051 was also calibrated for ozone column measurements. Since March 2013, weather permitting, D051 direct sun measurements have been recorded outside the higher-priority Umkehr measurement periods. Therefore fewer coincident ozone column measurements of instruments D051 and D101 were recorded. Figure 6 presents the daily values for the period 2012–2013 of Δ062–101 (red) and Δ051–101 (black) in the upper panel and the σi values in the lower panel. The increase in the differences in summer 2013 suggests a drift of the Dobson D101 instrument since the bias is similar for the two other instruments. However in March 2013, a change of the azimuth control system was introduced, and interference generated by this new system affected the measurements negatively. This problem was brought to light and solved in July 2013. In the first half of this MAC period, D101 was ∼ 0.5 % higher than D062, and by mid-2013 the three instruments agree. The lower panel shows the improvement of the data quality with a significant decrease in the random fluctuations: the automated instruments (D062 green and D051 orange) yield values around ∼ 0.3 %, while the manually operated instrument (D101 blue and light blue) is closer to ∼ 0.6 %. In Fig. 7, the monthly medians of Δ062–101, Δ051–101 and the σi are shown. With the exception of the period April–June 2013, the mean bias between the manual and automated instruments is within ±0.6 %, and the repeatability of the automated Dobson is significantly reduced in comparison to the manually operated instrument.
Figure 6(a) 2012–2013 time series of Δ062–101 (red) derived from coincident measurements of D101 (manual) and D062 (automated) and Δ051–101 derived from coincident measurements of D101 (manual) and D051 (automated) for 2013 (black). (b) Time series of σi of D101 (blue and light blue), D062 (green) and D051 (orange).
Figure 7(a) Time series of the monthly median of Δ062–101 (red) and Δ051–101 (black). (b) Time series of the monthly median of σi of D101 (blue and light blue), D062 (green) and D051(orange). The shading and the error bars correspond to the inter-percentile range IPR97.5th–2.5th of the various parameters.
Lines 2 and 3 in Table 3 show that D101 data are on average 0.19 % larger than D062 data. However, we are looking at a bimodal distribution due to the April–June 2013 period and the unevenly distributed measurements over the relatively short time period considered. Similarly, the positive value of Δ051–101=0.56 % is dominated by the spring 2013 period and the reduced sample of coincident measurements.
The 2012–2013 MAC comparison period shows that the agreement between manual and automated Dobson instruments is consistent and reproducible. Improved repeatability and the larger number of daily data are two of the prominent advantages of the automation.
4.3 Period of automated vs. automated collocated Dobson operation (AAC period)
D101 automation was achieved by July 2014, and the period of intensive comparison between collocated automated Dobson instruments started. The data set for the pair of instruments D101 and D062 covers the period July 2014–December 2015 and short periods in 2017 and in 2018. The second data set for the pair D051 and D062 covers the years 2013–2018. Since the relocation of D051 to Davos at the end of 2018, D101 and D051 have been collocated there for a new AAC period. Similar to Fig. 7, Fig. 8 compares the automated measurements of the three pairs of collocated Dobson instruments: D062–D101, D051–D101 and D062–D051. In March 2017, D101 was back to Arosa after a transfer to Germany to characterize its slit function (Köhler et al., 2018; Stübi et al., 2020). Again for the July–August periods 2017 and 2018, D101 was collocated with D062 and D051 in Arosa for two calibration and maintenance campaigns. These transfers could have altered the instrument response, but this is difficult to assess from these relatively short comparison periods. The monthly averages for these periods are also less representative since the sample is limited to only a few days in some cases. Notwithstanding, most data points lie within a ±1 % interval with periods of lesser agreement. Overall, the period 2016–2018 shows a convergence of the differences in the ±0.5 % range associated with the improvement and tuning of the Dobson instruments' control system. The time series of Δ062–101 (red strip in Fig. 8) is mostly within the ±0.5 % range except at the end of 2015 where D062 seems to be slightly lower. The Δ062–051 (blue strip) shows also a deviation at the beginning of 2016 but converges to the ±0.5 % range afterwards. The 2013–2014 period of the Δ062–051 time series indicates that the automated systems were not yet fully stable and that the bias could change by ±0.5 % over a year time period. As shown in the AAC section of Table 3, the Δ for the difference pair comparisons are not significantly different from zero except for the pair D051–D101 at LKO. As evidenced in Fig. 8, the 9 months between 2014–2018 mentioned in the table were not from a contiguous time period but typically reflect observations after D101 displacements. In contrast, in the 2019 period of collocation at Davos and after the 2018 calibration campaign, both instruments agree very well with an IPR97.5th–2.5th of ∼ 0.3 %. The lower panel of Fig. 8 suggests a repeatability of the three Dobson instruments of around 0.2 % with an IPR97.5th–2.5th between 0.08 % and 0.25 %. The values of σi summarized in Table 4 (lines 7–14) are surprisingly similar for the lower 2.5th percentiles (0.15 %–0.19 %) and the medians (0.20–0.25 %) of total ozone values. The 97.5th percentiles are on the order of 0.3 %–0.4 %.
Figure 8(a) Time series of the monthly median differences (%) between pairs of collocated Dobson instruments at Arosa over the period 2013–2019: Δ062–101 (red), Δ062–051 (blue) and Δ051–101 (black). (b) Time series of σi monthly medians: σ101 (blue), σ062 (green) and σ051 (orange). The shading and the error bars (plot every 2 months for clarity) denote the inter-percentile range IPR97.5th–2.5th.
The results presented up to this point underline the stability and repeatability of the automated Dobson measurements.
4.4 Period of automated vs. automated distant Dobson operation 2016–2019 (AAD period)
In January 2016, the D101 instrument was relocated to Davos with a setup similar to the one at Arosa. Since September 2018, the D051 instrument has also been relocated to Davos. The line-of-sight distance between Arosa and Davos is 11 km. The sites are sufficiently close to suggest a similar large-scale stratospheric ozone regime. However, the altitude difference between the two observatories is 250 m, which could translate into a slightly different total ozone column. Thus, total column ozone values at Davos are expected to be comparable or slightly larger than at Arosa. Since 2016, the data acquisition and computer-controlled operation have had minimal changes compared to the previous period of developments. Similar to the previous figures, Fig. 9 compares the Dobson pairs in terms of Δ and σ for the distant instruments. The Δ062–101 time series (red strip) is now mostly within −0.5 %±0.5 %, which could be an indication of an average offset between the two stations of the order of ∼ 0.5 %. The most recent data of 2019 tend to exhibit a smaller offset as also indicated by the Δ062–051 time series (blue strip). The Δ051–101 time series (black strip) has a very similar pattern which corroborates the agreement seen in Fig. 8 between D062 and D051. Table 3 (lines 8–10) shows that the mean ozone column difference between Davos and Arosa is −0.53 % ∈ [−1.05 %, 0.30 %] for the D062–D101 pair, −0.50 % ∈ [−1.09 %, 0.22 %] for D051–D101 pair and −0.58 % ∈ [−1.18 %, 0.05 %] for the D062–D051 pair. In the lower panel of Fig. 9, the variations of σi appear substantially larger than for the collocated cases. This is not too surprising since the two stations could certainly have different atmospheric conditions which influence the daily variations of the ozone column measured by the two distant instruments. In some cases, a time delay can be observed in the ozone variations at the two sites for example when a front is passing over the area (not shown). Attempts to systematically correct these time shifts did not improve the results significantly so they were not implemented. The 97.5th percentiles of the σ of the Dobson instruments at different locations reached 0.6 %–0.8 % mostly in winter. Such values were less frequent in the case of collocated instruments (Fig. 8). However, these observed larger σi variations do not significantly affect the monthly averages in Table 4 for the AAD cases, which were in the range of 0.1 %–0.4 %.
Figure 9(a) Time series of the monthly median differences (%) between pairs of Dobson measurements at two different sites over the period 2016–2019 with D062 at Arosa, D101 at Davos, and D051 at Arosa before September 2018 and at Davos after: Δ062–101 (red), Δ051–101 (black) and Δ062–051 (blue). Lower panel: time series of monthly medians of σi: σ101 (blue), σ062 (green) and σ051 (orange). The shading and the error bars indicate the inter-percentile range IPR97.5th–2.5th.
4.5 Seasonal cycle
For almost all optical measuring systems, a stray light effect is present with more or less influence on the measured values. The Dobson and Brewer sun spectrophotometers are no exception to this problem. The double-monochromator Brewer instruments are known to be free of a major stray light bias, but the single-monochromator Brewer as well as the Dobson instruments are affected (Moeini et al., 2019; Karppinen et al., 2015). The larger the ozone slant path (OSP = ozone amount * air mass) the larger the stray light effect, because the signal at the shorter wavelengths decreases more rapidly and gets to the noise level. As the OSP is naturally seasonally dependent and the stray light effect is instrument dependent, it is of interest to analyze a possible bias due to the OSP. As noted in Sect. 4.1, a seasonal cycle was observed in the 2005–2010 period, and the upper panel of Fig. 9 also shows a similar tendency. The result of the seasonal analysis of the Δ differences is presented in Fig. 10. The colored strips denoting the IPR97.5th–2.5th largely cover the zero line, but the lines of medians show a curvature with negative values in winter and positive values in summer. This is more pronounced for the AAD cases of the D062–D101 pair (in blue), where the amplitude of ∼ 0.8 % is twice as large as for the MMC cases (in red). The D051–D101 pair exhibits monthly differences that are more random. The 2018 intercomparison revealed an OSP-dependent bias between the European Dobson traveling standard D064 and both D101 and D051 but showed no such bias between D064 and D062. Without being firmly conclusive, the seasonal analysis suggests a possible contribution of a stray-light-induced bias caused by the D101 and/or D051 instrument.
Figure 10Annual cycle of the median differences of Δ (%): Δ062–101 in red for subperiods MMC and in blue for subperiod AAD; Δ051–101 in black for subperiod AAD.
In Sect. 4, the analysis of coincident measurements of three Dobson instruments from Arosa LKO is presented for four different configurations named MMC, MAC, AAC and AAD that refer to manual (M), automatic (A), collocated (C) or distant (D) operation of the instruments. The method used to separate the mid- to long-term systematic biases between instruments and the short-term random variations associated with each instrument were first presented in Stübi et al. (2017a). This method allowed us to reduce by half the overall global bias range from typically IPR97.5th–2.5th∼ 3 % (Table 2) down to IPR97.5th–2.5th∼ 1.5 % (Table 3).
The multiple calibration and maintenance campaigns over the 20-year MMC period result in the good agreement between Dobson instruments D101 and D062 independently calibrated against the regional secondary standard Dobson instruments. No significant biases were observed within the uncertainty associated with manual operations and the rather limited number of daily observations. Dobson instrument D051 was dedicated to automated Umkehr measurements which made direct sun observations very difficult.
The development of the Dobson automation from scratch took a few years with periods of hardware and software changes that impacted on the measurement stability. For backup measurements, D101 continued to be manually operated in parallel to the automated D062 and D051 over the 2012–2013 period. The analysis of the relatively short (1.5-year) MAC period shows an overall good agreement albeit with subperiods of biased measurements due to a malfunctioning of the automated system. Notwithstanding, the automated instruments proved to perform equally well or even better than a manually operated instrument. Dobson D051, which was newly used also for direct sun observations of the ozone column during the MAC period, yields larger ozone values compared to the manual Dobson D101 instrument. As shown in Fig. 6 and Fig. 7, the Δ values of the D062–D101 and D051–D101 instrument pairs are similar, as are the σi values. In Table 2, the mean differences for the MAC cases are not significant considering the large IPR97.5th–2.5th∼3.8 % for the coincident D062–D101 and D051–D101 values. From the refined daily analysis, the IPR97.5th–2.5th values have been reduced to ∼1.6 % (Table 3). Even though the values of the differences for the two pairs appear to be quite different (Δ062–101=-0.19 % vs. Δ051–101=0.56 %), they still remain close to ±0.5 %. Moreover, they represent averages of different time periods and sample lengths and should be compared with caution.
Beginning in 2014, all three Dobson instruments were ready for automated and collocated (AAC) operation. For a while, as shown in Table 1, the operating environment was still changing from time to time, and the system was subject to occasional technical glitches. Table 2 shows that the direct comparison differences for the AAC case are not significant with 10-times-larger sample sizes than in the MAC case. The daily analysis results from Table 3 confirm the excellent agreement between D062 and both D101 and D051, while the pair D101 and D051 presents a barely significant value of Δ051–101=0.30 % ∈ [−0.32 %, 0.77 %]. As mentioned in Sect. 4.3, the D051–D101 coincident data sets were recorded for three distinct periods (black symbols in Fig. 8) with reduced sample sizes and are therefore less representative. The recent 2018–2019 period of coincident measurements at Davos with a value of Δ051–101=0.13 % ∈ [−0.08 %, 0.22 %] confirms the excellent agreement between the D101 and D051 instruments. In summary, the automated Dobson systems were very reliable and reproducible during this AAC comparison period.
Considering the homogeneity and continuity of the Arosa–Davos ozone column time series, the comparison of coincident data obtained independently at the two stations is an essential part of this study. A similar analysis by Stübi et al. (2017b) considering the long-term stability and random uncertainties of the Brewer instruments found no significant differences between the Arosa and Davos sites. The analysis of the AAD period presented in Sect. 4.4 arrives at the same conclusion. Notwithstanding, the last three lines in Table 2 may indicate the possibility of a ≃ 0.4 % systematic high bias within an IPR97.5th–2.5th of 2.5–2.9 for the instruments located at Davos. The daily analysis results in Table 3 confirm these numbers with Δi values of ≃ 0.5 % but with a reduced IPR97.5th–2.5th of ∼ 1.3 %. In Stübi et al. (2017b), the authors estimated that the Arosa–Davos altitude difference of 260 m could contribute 0.25 % ± 0.15 % to the ozone column. Therefore half of the observed difference could be attributed to the longer ozone column measured from Davos. The σi values reported in Table 4 are consistent and demonstrate the benefits of automation. Manual operation of the Dobson instrument yields values of σ≃0.40 % ∈ [0.3 %, 0.7 %] on average. The automation of the operations reduced these values to σ≃0.25 % ∈ [0.15 %, 0.40 %]. These numbers are slightly lower than the corresponding Brewer values of around 0.3 %–0.4 % reported in Stübi et al. (2017a) (Table 3) and León-Luis et al. (2018) (Table 4). These values further confirm the good quality of the automated Dobson measurements.
The slight seasonal component presented in Sect. 4.5 is probably responsible for the ripples observed in Figs. 8 and 9. Even though all Dobson instruments are based on a similar design, the stray light bias is instrument dependent. An improved processing algorithm including stray light correction as presented in Moeini et al. (2019) could be applied for the Arosa–Davos data since Brewer double monochromator instruments are collocated. Recent slit function measurements of the Arosa Dobson instruments are now available from the ATMOZ project (ATMOZ Project, 2018). However, such improvements were beyond the scope of the present analysis. Similarly, the characterization of the first few kilometers of the ozone profile and its seasonal cycle in the Arosa and Davos valleys, to more accurately assess potential differences of the free troposphere ozone column above these two sites, needs to be referred to future research.
The present results based on Dobson data confirm the conclusion reported in Stübi et al. (2017b) based on Brewer data. Biases found are not statistically significant at the IPR97.5th–2.5th level and, therefore, could not be systematically compensated for. A reprocessing of the Dobson and Brewer data sets with an improved algorithm based on recent ozone cross-section values and improved stray-light correction based on better slit functions as described in Gröbner et al. (2021) could perhaps reduce the uncertainties on the biases found but would most certainly not change our conclusions. The results presented in this study are unique since no other station of the Dobson network has operated fully automated collocated Dobson instruments over a multiyear time period. Considering the importance of the Arosa time series, research will continue with a focus on trend analyses and break detection of the series both on data from Arosa (continued until February 2021) and data based on the combined Arosa–Davos time series.
The data used for this analysis are available at the WOUDC for the Dobson D101 (1992–2014) and D062 (2014–2020) instruments. The complete data sets can be requested by direct contact with the corresponding author.
RS was mainly responsible for the data analysis and the first version of the manuscript. HS was in charge of the quality control and the preparation of the data sets. JK, EMB and AH contributed to the data interpretation and revisions of the manuscript.
The authors declare that they have no conflict of interest.
We would like to thank the PMOD/WRC staff for their great support in running our instruments in their premises and for the excellent collaboration.
This paper was edited by Alexander Kokhanovsky and reviewed by two anonymous referees.
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Dobson spectrophotometer measurements
Data sets of coincident measurements
Total ozone column has been measured since 1926 in the Swiss Alps station Arosa. These worldwide series are based on Dobson sun spectrophotometers. To assure the continuity of these series, a two-stage project was realized at MeteoSwiss: first, Dobson instruments were automated, and then parallel measurements between Arosa and a nearby site in Davos were carried out. The analysis of the data of the manual-to-automated transition and coincident data between the two sites are presented here.
Total ozone column has been measured since 1926 in the Swiss Alps station Arosa. These worldwide...


Thanks to the rain this week, Gardner City is no longer under water restrictions. I really have the feeling that a lot of people didn't know we were supposed to conserve, but hey it's over for now.
I try to stay out of the political arena here in town or even nationally. I vote, I make my preferences known the way we are supposed to. Sometimes my candidate wins, sometimes they lose. Sometimes I get sick of the negative campaign ads that assault us on TV.
You provide facts. Sometimes they are boring and uneventful. They are at times, sad and heartbreaking.
Citizens need to take care when selecting their representatives. After all they are the ones who get the publicity when things go awry.
Elected officials need to listen to all the people they represent who are willing to speak up. Not just the few that you see at church or at your local cook outs.
We don't need to be the laughing stock of the county. We don't need to be the good ole boys network.
Who will be my 'first to contact' person?


Universidad Católica de Chile is one of the six Catholic Universities existing in the Chilean university system and one of the two Pontifical Universities in the country, along with the Pontifical Catholic University of Valparaíso. It is also one of Chile's oldest universities and one of the most recognized educational institutions in Latin America. According to the QS Ranking, its Faculty of Law ranks 38th in the world, and its Faculty of Education ranks 33rd worldwide.


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"Kite" is a prison term for an informal message or a complaint. According to one theory, the term originated in the mid-1800s when prisoners were not allowed to speak and instead passed messages to each other using Kite branded cigarette rolling papers. Another theory holds that the word came from the practice of people communicating with others by attaching a note to a string and swinging it to their friend's cell, much like a kite.
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2019 End of Year Campaign Wrap Up - Thanks for Helping Tor Take Back the Internet
by Sarah | January 15, 2020
We believe Tor is strongest when it is used by and supported by as many people as possible. A diverse user base strengthens the anonymity of Tor users, and diverse funding sources ensure we are only beholden to our mission -- no single financial source.
We are pleased to announce that we raised more funds in 2019 from individuals than ever before -- $833,956! This is almost double what we raised in 2018. A little over $300,000 of this income was donated during our end-of-year campaign and was generously matched by Mozilla. Thank you to everyone who contributed. You are helping Tor take back the internet.
In 2019, 10,404 people made their first donation to Tor. It is exciting to see so many people understand and commit themselves financially to our mission. Even more exciting is that, during the campaign alone, we gained 330 new Defenders of Privacy -- donors who make a monthly commitment to Tor. Sustaining gifts provide the Tor Project with steady, reliable income that is essential to our ability to respond quickly to unexpected challenges and threats. We also had eight donors make new contributions of $1,000 or more, making them Champions of Privacy.
Our commitment to privacy extends to our donors. We execute our fundraising in a way that is very different than other nonprofits. We never share your information with third parties. We never receive potential new donor information from outside sources. We do not track the behavior of our donors when you open our emails. We allow donors to choose what information you share with us. You can be more anonymous by sending a money order to our physical address or utilizing cryptocurrency to protect your personal information. Privacy is limited by requirements of the most popular donation methods, PayPal or credit card, but we are committed to offering privacy-preserving methods of making donations.
This income raised from individuals is essential for us to make progress on our 2020 goal to scale our network, making Tor easily accessible to everyone, while providing privacy online and tools to circumvent censorship. As Isabela Bagueros, our executive director said, "How do we actualize a more private, decentralized, equitable internet? It will take a lot of work and a unified vision. It takes preparing the Tor network to handle more users by scaling the network and improving its performance metrics. It takes the Anti-Censorship team working on circumvention solutions that are difficult and expensive for censors to block, but easy for us to deploy and scale. It takes the Tor Browser, Community, and UX teams working together to make Tor more accessible to the people who need it the most." We have that unified vision. With your help, we are ready to take on this work.
You make a difference. Your help contributed to our goal of taking back the internet with Tor! Thank you.
The Tor Project Fundraising Team
take back the internet
Click-to-play video doesn't…
Click-to-play video doesn't work on Safer to watch the videos in this blog. What a shame!
In reply to Click-to-play video doesn't… by Anonymous (not verified)
Thank you. They're working…
Thank you. They're working on it: https://trac.torproject.org/projects/tor/ticket/33000
What about help for Tor…
What about help for Tor users? You have so much money. What about full guides for making onion services? (How to set up and configure web server, how to configure onion service, how to make onion site, forum or game.) What about specific tools for people who can't understand computers at all? Or any online support via tor browser? Also is it possible to make onion service online not every time when computer online? For example computer online few hours but onion service online only one hour?
In reply to What about help for Tor… by Anonymous (not verified)
I'd like to see those things…
I'd like to see those things too, but regarding
> You have so much money.
Far from it; Tor Project is very underfunded and understaffed when compared to the enormous global responsibility of producing one of very few (so far) privacy/anonymity tools which should work for virtually anyone anywhere in the world, modulo gaining access to torproject.org to download the software (and possibly bridge addresses) in the first place.
So I'd put it like this: we'd like to see lots of things on TP's "to do" list, but accept that
o bug fixes
o research into scaling the Tor network
o global outreach and security trainings (Luanda needs TP's help! So do student groups in Puerto Rico!)
o carefully vetting prospective new Tor employees to keep out agents working undercover for some government or evilcorp (c.f. the apparent attempt by CIA to plant a "former" spook inside TP),
o moving TP to a user donation funding model
o (arguably) seeking short term "no strings" grants from foundations and (distasteful) corporations (where is Apple? why only Google and USG shills?)
o (arguably) basic research into anonymity and onions generally
should probably have a higher priority.
But with all that said, would making manuals really take so much time?
> What about full guides for…
> What about full guides for making onion services?
Look here:
https://community.torproject.org/onion-services/
https://2019.www.torproject.org/docs/onion-services.html.en
https://2019.www.torproject.org/docs/tor-onion-service.html.en
Those guides need to be labeled better and linked to better so they're easier to find (talking to you, Tor Project!). As for web servers, forums or games, there are many choices of software designed for the regular internet that you could host on an onion service, and they are quite separate from Tor software. Be sure to inspect them for privacy and metadata leaks as most are not audited as strictly as Tor is.
I, myself, would like for the following pages to be expanded and for there to be a guide to anonymously contributing by Git over Tor.
https://trac.torproject.org/projects/tor/wiki/doc/TorifyHOWTO
https://trac.torproject.org/projects/tor/wiki/doc/SupportPrograms
This is insufficient for contributing over Tor, and it's hard to access and interpret for those outside of Tor's development teams: https://gitweb.torproject.org/githax.git/tree/
> What about specific tools for people who can't understand computers at all?
https://2019.www.torproject.org/projects/projects.html.en
https://2019.www.torproject.org/getinvolved/volunteer.html.en#Projects
For those people, the best tools that Tor Project recommends are arguably HTTPS-Everywhere, Tor Browser, TorBirdy, OnionShare, Orbot, Tails, Metrics, Onionoo. I would also recommend Privacy Badger, another add-on by EFF for regular web browsers.
> Or any online support via tor browser?
Across the top header of torproject.org, there's "Support", "Documentation", and "Community". When you open Tor Browser or start a new identity, the purple page has a link under the search box, "Questions? Check our Tor Browser Manual".
> is it possible to make onion service online not every time when computer online? For example computer online few hours but onion service online only one hour?
In that context, think of an onion service like any other web service: the computer or server it runs on must be online. Your example of the computer being on for longer than the onion service is entirely possible, and you can command the service to stop like any other daemon for the regular internet such as for HTTP (like Apache, nginx) or FTP (like FileZilla Server), but an example of the reverse where the onion service is online longer than the computer is not possible, obviously, because the service runs on the computer. You could host onion services on a VPS or dedicated server purchased at data center or CDN if you find a way to trust it. There also are distributed networks other than Tor such as IPFS that have limited capabilities to host static websites facing the regular internet.
> We are pleased to announce…
> We are pleased to announce that we raised more funds in 2019 from individuals than ever before -- $833,956! This is almost double what we raised in 2018.
This is very welcome news, and I take it as an encouraging indication that if TP perseveres in the effort to transition from dependency on USG funding to a grassroots user-donation funding model (similar to ACLU, EFF, and other major organizations) is achievable. I think most of us now agree it is also necessary, so evidence that it is possible is very good news indeed!
I sense that all around the world, more and more people are becoming more and more concerned about the dangers posed to essentially everyone by both government dragnets/targeted-hacking and surveillance capitalism, are becoming more mistrustful of Big Tech consumer goods and services type companies and of their own government, and consequently are liable to become Tor users/donors in the near future.
The recent revelation (and prompt fix, thank you) of another critical in Tor Browser (at the "standard" security level--- "safer" or even "safest" should really be the default) has again underscored the fact that we can expect many more technical attacks on Tor users in the future, and discovering and countering these will likely be a top priority for the Tor teams in the years to come. But we must also regard the political/legal threat from AG Barr and his ilk as posing an existential threat to TP, so defeating this threat must also be a top priority:
arstechnica.com
The broken record of breaking encryption skips again in Florida shooter case
Trump's Twitter tantrum doesn't change the laws of mathematics. Neither does Cellebrite.
> On the eve of the House of Representatives' forwarding of articles of impeachment to the Senate, President Donald Trump took time to attack Apple. The president's outburst on Twitter appears to be about the FBI's inability to get access to the physical storage on two iPhones connected to last month's killings at Naval Air Station Pensacola in Florida. And it is the latest ratcheting up of rhetoric from the Trump administration on device encryption.
Apple calls BS on FBI, AG: We're totally not dragging our feet in murder probe iPhone decryption. PS: No backdoors
This isn't the way to make the Cook(ie) crumble
Kieren McCarthy in San Francisco
Susan Landau and other crypto experts are still trying to convince the Feds that extremism won't help anyone (except maybe, very briefly, Drump, as a temporary distraction from his trial in the Senate):
Breaking the encryption impasse
Denis McDonough and Susan Landau, opinion contributors
As further evidence that TP needs to do more to correct anti-onion bias, here is yet another story which mentions onions in a derogatory context but fails to mention that onions are mostly used to protect people, not to harm them:
FBI arrests man suspected of orchestrating dozens of "swatting" calls
Group's online chats were often racist and anti-Semitic.
Timothy B. Lee
> The US government has criminally charged a Virginia man for helping to organize dozens of "swatting" attacks and bomb threats made against a variety of targets in the United States and Canada. The man allegedly belonged to a group that coordinated via IRC and Tor hidden services to target prominent gamers, journalists, and government officials.
In other news on the legal front, privacy advocates around the world should be cheered by the fact that the top EU lawyer has issued a (non-binding) brief to the top EU court arguing that a suspicionless dragnet is illegal in the EU:
Top Euro court advised: Cops, spies yelling 'national security' isn't enough to force ISPs to hand over massive piles of people's private data
Opinion is preliminary, though a good start
> Analysis In a massive win for privacy rights, the advocate general advising the European Court of Justice (ECJ) has said that national security concerns should not override citizens' data privacy. Thus, ISPs should not be forced to hand over personal information without clear justification. That doesn't mean that the intelligence and security services should oblige communications companies to hand over information, especially when it comes to terrorism suspects, the opinion, handed down yesterday, proposes. But it would mean that those requests will need to be done "on an exceptional and temporary basis," as opposed to sustained blanket harvesting of information – and only when justified by "overriding considerations relating to threats to public security or national security." In other words, a US-style hovering up of personal data is not legal under European law.
I interpret this event to show that our side and win the legal victories we need--- currently, most urgently in the US and EU--- to have a chance of continuing to exist, which would mean that we will have a chance to continue to fight off technical threats, while continuing to read and discuss, to blog, to do journalism, to engage in politics, and generally to do what we can to ensure that civil society does not die in the 21st Century.
I encountered an unexpected…
I encountered an unexpected connection to youtube.com when I viewed this blog page. Is this expected behavior? If so, is it wise for the Tor blog to force connections to Youtube while Tor users are viewing this blog?
In general, it seems that viewing videos is one of the most hazardous things an unwary person can do using Tor Browser--- an assertion which was very recently supported by yet another critical vulnerability which only affected people using the "Standard" security level, which appears to be needed (as another commentator said above) to view videos with Tor Browser. I assume TP would not quarrel with this statement. If so, it would appear to follow that the Tor blog should not include links to Youtube. If videos are not really needed, they probably do not belong here.
I guess that the videos are an attempt to lure more newbies into trying Tor, but if so I think it would be wise to find safer way to do that.
Any information about amount…
Any information about amount of donation using cryptocurrency?
In reply to Any information about amount… by Anonymous (not verified)
We've received $107,000 in…
We've received $107,000 in cryptocurrency since the beginning of our fiscal year on July 1, 2019. Much of this was donated during the year-end campaign.
scooter (not verified) said:
I just bought the domain www…
I just bought the domain www.darkndeep.com and forwarding it to your main site. Hope it gets more visitors for you
ratoe (not verified) said:
Disable electrosys in…
Disable electrosys in Firefox!
TBB launched, no page visited = 10 firefox tcp connections + 20 tor connections. What the hell is that?
In reply to Disable electrosys in… by ratoe (not verified)
> electrosys Never heard of…
> electrosys
Never heard of that.
Did you mean Electrum? Were you launching Tor Browser in Tails, a Debian system, a Windows system, or another?
> no page visited = 10 firefox tcp connections + 20 tor connections. What the hell is that?
Is it possible that you mis-interpreted expected and desirable behavior (your Tor client building Tor circuits for your use in next few minutes) as evidence suggesting malicious compromise?
Without more details I think it is impossible to know what you observed or what it might mean.
(Caveat: I am just another Tor user, not a Tor dev.)
It's *Electrolysis.https:/…
It's *Electrolysis.
https://duckduckgo.com/?q=firefox+Electrolysis
The Cloudflare Network is…
The Cloudflare Network is blocking me today with error message 1001, Cloudflare Ray ID: 557b22023c366d04. It does this periodically, and I can usually access the same site on its network. Thanks.
In reply to The Cloudflare Network is… by Joe (not verified)
> The Cloudflare Network is…
> The Cloudflare Network is blocking me today with error message 1001
FWIW, I see similar messages quite often (e.g. at news sites) and simply ignore them. The long numerical code appears to be a counter used to identify individual connections to some site, which Cloudflare's robots deem "suspicious" (a connection from a Tor exit node apparently often counts). The counter apparently increments until it rolls over and starts again.
Sometimes waiting a few days and trying to surf (using TB) to the same site works. It is possible that Cloudflare blocks are associated with activity at certain sites which is suspicious for more alarming reasons than simply connecting from a Tor exit node.
Speaking of censorship…
Speaking of censorship messages, there's a page on the Tor wiki if you want to learn more and help out.
https://trac.torproject.org/projects/tor/wiki/org/doc/ListOfServicesBlo…
@ tor (not verified) said:
We need TorBirdy updated for…
We need TorBirdy updated for thurderbird 68 sooner over later
Bill tomas (not verified) said:
I'm concerned about hidden…
I'm concerned about hidden fees , is this something I need to concern myself with ?
In reply to I'm concerned about hidden… by Bill tomas (not verified)
Tor is completely free to…
Tor is completely free to use.
> I'm concerned about hidden…
> I'm concerned about hidden fees
This issue is indeed a legitimate concern for North American internet users. The hidden fees are charged by the big ISPs (e.g. Comcast, Century-Link) because these companies cannot actually deliver service while charging their up-front "low low" user fees and also funneling torrents of cash to the shareholders and company executives, so they are all tacking on hidden fees in order to continue what they consider "business as usual", to the detriment of everyone else.
Conservatives might notice that hidden fees are a major distortion of the alleged free market; so are the monopolies typically enjoyed at least locally by the big ISPs. Liberals are likely to object to the way this situation exacerbates income inequality and mendacity, thus further destabilizing civil society. So this issue should concern everyone who uses the Internet (at least in North America), regardless of their political stance.
However, this has nothing to do with Tor Project or even with Tor. You should express your concern to your representatives in Congress and to municipal authorities who often have a suspiciously cozy relationship with the big ISP which enjoys a local monopoly in a given service area.
See arstechnica.com and techdirt.com for lots more information about this issue.


JAMES VINCENT CARROLL | Welcome to the official site of James Vincent Carroll (formerly Jamie Carroll Music) | Who Am I?
Who am I and why should you hire me?
My name is James. You may not know me yet.
Many of you have known me my entire life and many of you have met me over the last 25 years of my music career.
I became a career musician in 2013 after YEARS of learning what worked and what did NOT work for me in the "music industry".
I write songs, record albums and mostly PERFORM between 200-300 events of all types per year to make my living.
I have two sons (currently ages 13 and 16). My oldest son has lived with me since he was in 5th grade.
I say often that I am "not a typical musician" due to my main desire of bringing people TOGETHER with my live shows. I have seen people come together and make life long friendships and relationships just by attending my shows over the years and THAT continues to be one of the most rewarding parts of what I do.
I love supporting local businesses who realize that supporting OTHER local businesses is successful for all of us!
I have learned that in order to do what I am best at I must live simply and WORK long hours by booking, performing and PROMOTING myself AND the businesses that hire me regularly.
*EVEN WHEN I AM NOT PERFORMING I AM PROMOTING THESE BUSINESSES AND TELLING MY FAMILY, FRIENDS AND FAN BASE TO FREQUENT THEM ALL.
My one "luxury" in life is my life long love and enthusiasm for Motorcycles. As long as I have health I will create music and ride my Harley.
My monthly living expenses are manageable (most of the time, lol). My largest payment is rent (for now) and I have plans of a MAJOR downsizing as soon as my kids are out of High School and "move on into their adult life".
For now... this is it. THIS is what I do and I try and hope to share it with everyone who believes in me and understands why it is important.
I WILL continue SHARING my life's work with ALL who desire to be a part of it.
Any event, any musical need.
Since I began at the age of 15, I have toured, written and recorded under my childhood name "Jamie Carroll".
With the birth of my FULL TIME MUSIC CAREER in April of 2014 I have chosen to adopt my birth name, James Vincent Carroll for all future projects and promotion.
I have learned that my mistakes in life may have not been mistakes at all, rather choices and decisions that taught me lessons on how to be authentic and I try to write songs that reflect what I have learned along the way.
I support and promote local music so if you're looking for more Artists to perform at your venue, please feel free to contact me about them as well.


With CES just around the corner enthusiasts across the board are on the look out for the latest cameras and other accessories that will be announced at the show. Already we've told you that the Nikon D4 DSLR will officially show its face at CES 2012 and that Fujifilm will be coming forth with a full 19 camera line up. We also told you about Fujifilm's X-Pro1 which had its entire spec sheet leaked prior to an official announcement. However, during the leak we were not notified when exactly we would be hearing these specs officially confirmed leaving their authenticity up in the air.
Luckily, yet another leak has surfaced today that tells us when the Fujifilm X-Pro 1 will officially be announced. According to recent reports, DPReview.com recently went live with a placeholder for the X-Pro 1 that showed an announcement date of January 9th. As of this writing the placeholder has seen been pulled but a cached version of the page confirms this which can be viewed here.
Now, while we don't have official confirmation that this will be the announcement date the fact that they quickly pulled the placeholder does put some weight behind this rumor. Furthermore, CES 2012 is currently set to run from January 10 – 13 and a pre-show announcement from Fuji is not a very far fetched concept.
As always, before you get too excited, stay tuned as we attempt to dig up more on this.


This thoughtful and accessible book provides a critical examination of the central debates attached to conceptualizing sexuality as a site of knowledge and politics. These are explored in chapters on the meaning of heterosexuality, sexual citizenship and the associated notions of sexual rights and obligations, queer theory and its relationship with feminisms, both `new' and `old'. Also included is discussion of responses to the HIV//AIDS epidemic and the implications for understandings of gender and sexuality.


text:
Mayweather vs McGregor – The Party is Finally Over
By Gary Todd
Las Vegas- Floyd Mayweather , as expected, took Conor McGregor to school, and gave the Irish plodder , a painful lesson in the sport of boxing. The loud mouthed McGregor could not back up on anything he said in the build up to the fight, and in the end, he showed that in life, talk only gets you so far.
McGregor was terrible, and although we knew he couldn't box, I was amazed at how bad he really was. People have said he fought well enough to put Mayweather off his game, and to this I would disagree . Mayweather was in total control and knew exactly what he was doing from the sound of the first bell. McGregor had to come forward and land shots anywhere he could. Don't be fooled that he was throwing punches from weird angles, what do you think happens in an amateur bout. I remember my first amateur fight, and I had trained hard for a year, training alongside pro's and I had practiced combinations until I knew them off by heart, but come fight night, all that went out the window, and all we could do was get in there and throw punches. Mayweather sat back, smiled, and wound up McGregor and let him go.
As soon as McGregor started throwing shots, I knew "Mystic Mac" and his ridiculous predictions of taking out Mayweather in the second round, or any round for that matter were just talk. When it got to the 5th round, and Floyd pushed him , before going to his corner, smiling and playing to the commentators at ringside, I knew that it would just be a matter of time. McGregor was already showing visible signs of distress, and went from being flat footed , every time Floyd touched him, and his stare was like a deer caught in the headlights, to then change into "Bambi" with his legs going to jelly on an icy pond. The Irish MMA star was not only gasping for air after 21 minutes, he was exhausted, and hanging on for dear life. As soon as he realized that hitting Mayweather on the top of the head, throwing hammer punches, and hitting Mayweather behind the head, just wasn't going to work for him, it was the beginning of the end. As soon as he knew the big age difference was to count for nothing , and as soon as he realized his much advertised power shots were hitting air, and the power he thought he had would transcend from the Irishman's 170 pound body, on to Mayweather's chin, when it didn't, it was him who " was fucked" McGregor could barely stand up straight, let alone lift his shoulders up or his arms up to throw a decent punch .
Before the fight, he had said, " with his little legs, with his little core, his little head, I am going to knock him out inside four rounds, mark my words " , reality had now set in, and it turned out that it would, be his own little legs, his little core, and his little head that would betray him tonight. Stamina, resilience, and boxing experience are always the key to being a boxer. It takes years to control , to use it, so you conserve energies within. Mayweather's has honed this forever, fighting in the amateurs, the Golden Gloves, to the Olympics, to then build on those essential qualities and skills , into one of the best fighters of all time.
By the 7th round, Mayweather was teasing, playing with him, before punishing him with hurtful punches , whenever he chose to, and McGregor couldn't do a thing about it. At the end of the round, Mayweather Snr, told his son that he could take him out anytime he liked, and it wasn't long before he did just that.
McGregor's legs were all over the place, defense in tatters, his torso, either bouncing off the ropes, to at one point, he put his two elbows draped across the top rope as he needed a rest. It was unbelievable to watch. It was a disgraceful display , from the man who would be king.
By the 10th , Mayweather only had to throw straight right hands and McGregor was ready to go, and that's what he did. McGregor was going , going, gone, and Referee, Robert Byrd stepped in, to save the Irishman from being totally destroyed in the 10th round. For the 14, 623 fans in attendance, the fight was over. They partied on, but for McGregor, and his short glimpse into the world of boxing, the party was over for him.
As a note, I thought the referee was abysmal . He knew the rules, he preached to McGregor before the fight, yet he allowed McGregor to continually hit Mayweather, behind the head, and on top of the head, by my count of 7 times, and not once did he mention taking a point away.
Gary Todd has been involved in all aspects in the sport of boxing for over 25 years, and he is the proud author of his books on boxing's world champions, " Workouts from boxings greatest champs vol. 1 and 2"


text:
Professor Jules Boykoff to Speak on Olympics and Politics at Portland City Club on Friday, Feb. 7
Pacific University (Ore.) associate professor Jules Boykoff, an expert on the politics of the Olympic Games, will be the featured speaker at the City Club of Portland's next Friday Forum, set for 12:15 p.m., Friday, Feb. 7. Boykoff will present Money, Politics & the Olympics.
Oregon Public Broadcasting radio broadcasts each forum on Friday evenings from 7 to 8 p.m.
Boykoff is an expert on politics and the Olympics. His most recent essay on the subject, co-authored with Dave Zirin, appeared in the San Francisco Chronicle on Jan. 23.
Addtionally, Boykoff provided his thoughts to Agence France Press on Russia's anti-gay laws as the 2014 Sochi games near.
Boykoff presented a talk titled The Olympics: Celebration Capitalism on Jan. 10, and will be part of a panel discussion, Five Ring Fever: The Sochi Games and Celebration Capitalism on Tuesday, Feb. 4 in New York.
He will also provide analysis on the British Broadcasting Company's Business Daily in a story titledThe Olympic Brand scheduled to air on Saturday, Feb. 1.
jules boykoff


Intern year has kept me busy and on my first weekend free in a long time, I decided it was time to finally show my significant other that the chef he is dating actually does know how to cook (yes, this is a running joke). However, the unseasonally early snow storm on the East Coast, and a grocery delivery not scheduled until tomorrow, definitely gave me the opportunity to prove that I'm a cook worth my salt. The hunt began to see what could be put together from the pantry and freezer along with a lingering head of cauliflower in the fridge. The following if what I came up with (apologies for the lack of pictures...remembering to take photos is now added to my promises of renewed blogging frequency!).
Bengali "five spice" aka. Panchphoran (featured in two of the following recipes) is made by mixing equal parts of the following whole spices: nigella, fenugreek, brown or black mustard seed, cumin seed and fennel seed. I first tried this while living with a Bengali roommate. She wasn't much of a cook, but her mother was and would send boxes of delicious smelling sauces, seasoning and meals (can I have a Bengali mother?). After asking my roomie to let me investigate her mystery spices, I came up with the following concoction. I've since realized (through the miracle of Google) that this is, indeed, what Bengali "five spice" is and that it's proper name is panchphoran. It is so delightfully different that the flavors that I generally get going out for Boston Indian food that I like to keep a container of it around when I want to cook something from that region of the world.
Rinse lentils well in a strainer.
Heat oil in medium-large saucepan.
Toast cumin and Bengali "five spice" until fragrant but not dark.
Add diced onion, tomato, paprika and chilies and cook on medium for a 2-4 minutes stirring occasionally so that cooking begins but no browning of the vegetables occurs.
Add lentils and 4-1/2 cups of water to the pot. Bring to a boil and reduce heat to a simmer.
Add salt, stir well, cook another 30 minutes. During this final portion of the cooking, stir well to break up some of the lentils every 5-10 minutes.
Heat 2 Tablespoons oil in large sauté pan. Add potatoes and brown sides. Remove potatoes from pan and set aside.
Add 1 Tablespoon oil to the pan and brown cauliflower; remove from pan.
Add final Tablespoon of oil to the pan along with fresh ginger if using and mustard seed and stir to toast until seeds begin to pop.
Add chickpeas, cauliflower, potatoes, dried ginger if using, cumin and coriander, turmeric, salt and chilies.
Add ½ cup water, stir well and cover to steam.
Allow to steam 5 minutes before serving.
Heat oil and Bengali "five spice" in a small saucepan until fragrant but not dark.
Add mango, salt, ginger, garlic, vinegar, sugar, turmeric and cayenne.
Stir all ingredients and bring to a simmer over medium heat. Allow to cook uncovered for 5 minutes to thicken a bit, stirring occasionally.
Reduce heat to low and cook barely simmering for 30 more minutes, stirring occasionally.
Put into a clean glass or ceramic jar to cool and cover with a non-corrosive lid. Keep refrigerated. It can be eaten right away, but keeps for weeks in the refrigerator.
Blend ingredients together until completely smooth. Store in the refrigerator.
Turn a large burner on an electric stove or heat a cast iron pan well over a gas flame. Use tongs to flip the papad as it puffs, crinkles and develops little tiny bubbles on each side and dulls in color throughout while getting tiny charred spots in a few places. It works best to flip a few times quickly so that both sides get done without it curling up on you. On an electric stove, you can put it right on the burner. For the cast iron pan, there is no need to oil the pan.
On each plate, I placed a serving of the Lentils and Aloo Gobi with Chana each with a dollop of of Vegan Yogurt Substitute on top. Mango chutney was on the side, but quickly got mixed into the Aloo Gobi and the yogurt throughly mixed into both dishes. We used toasted cumin seed papads to scoop up chutney and lentils as well.
This definitely got two thumbs' up - and an S.O. that believes I can cook!


text:
package org.locke.biokit.chemistry.atom.orbitals.quantum;

import java.util.Objects;

public class SpinSet
{
	public static final SpinSet EMPTY = new SpinSet();

	private final Spin up;
	private final Spin down;

	public SpinSet()
	{
		this(null, null);
	}

	public SpinSet(final Spin up, final Spin down)
	{
		this.up = up;
		this.down = down;
	}

	public Spin down()
	{
		return this.down;
	}

	public boolean isEmpty()
	{
		return this.up == null && this.down == null;
	}

	public boolean isFull()
	{
		return this.up != null && this.down != null;
	}

	public SpinSet spins(final Spin one, final Spin two)
	{
		return new SpinSet(one, two);
	}

	@Override
	public String toString()
	{
		return (this.up != null ? this.up.toString() : "") + //
		        (this.down != null ? this.down.toString() : "");
	}

	public Spin up()
	{
		return this.up;
	}

	public SpinSet with(final Spin spin)
	{
		Objects.requireNonNull(spin);

		if (spin.isUp())
		{
			if (this.up == null)
			{
				return new SpinSet(spin, this.down);
			}
			else
			{
				throw new IllegalArgumentException("SpinSet already contains an up spin");
			}
		}

		if (spin.isDown())
		{
			if (this.down == null)
			{
				return new SpinSet(this.up, spin);
			}
			else
			{
				throw new IllegalArgumentException("SpinSet already contains a down spin");
			}
		}

		throw new IllegalStateException();
	}
}

redpajama_set_name: RedPajamaGithub