The MODIS is one of the key instruments of NASA's EOS mission and is currently operating on both the Terra and Aqua satellites. It has 20 reflective solar bands (RSB) with wavelengths from 0.41 to 2.2µm and 16 thermal emissive bands (TEB) from 3.7 to 14.4µm and makes observations at three nadir spatial resolutions: 0.25km, 0.5km, and 1km. The sensor's on- orbit calibration and characterization are performed using its on- board calibrators (OBCs) that include a solar diffuser (SD), a solar diffuser stability monitor (SDSM), a blackbody (BB), and a spectro-radiometric calibration assembly (SRCA). This paper provides an overview of MODIS on-orbit calibration and characterization methodologies, operational activities, and instrument performance. For both the Terra and Aqua MODIS, SD degradation results derived from the SDSM data show similar wavelength dependencies when operated under the same conditions, with annual reflectance decreases of 3% at 0.41µm, 1.6% at 0.47µm, and 0.7% at 0.53µm. The blackbody used for the thermal emissive bsans calibrations has been extremely stable with an average temperature drift of less than 0.005K per year. Its short-term (or scan-to-scan) temperature variation is within ±0.03K. The SRCA overall performance has been satisfactory, providing useful information for the sensor's on-orbit spectral and spatial characterization. Other calibration issues such as sensor's response stability, noise characterization, and scan mirror degradation, are also discussed. I. INTRODUCTION
['Xiaoxiong Xiong', 'Vincent V. Salomonson', 'William L. Barnes']
Overview of the EOS/ MODIS on-orbit calibration and performance