ECOSYSTEM PROPERTIES FOR WHICH SATELLITE DATA ARE REQUIRED
measurement of canopy height with lidar. Others are derived from
the statistics of direct measurements, such as estimates of
landscape heterogeneity used in conservation biology and
ecosystem management and the inference of surface sources and
sinks of CO2 from space-based measurements of column-integrated
atmospheric CO2. A third category includes quantities that
result from using direct observations as inputs in physical,
biological, or statistical models; an example is the estimation
of carbon uptake and release through photosynthesis and
respiration in marine or terrestrial systems, which are inferred
from space-based estimates of photosynthetic light absorption. A
final category includes quantities estimated from time series of
measurements, which by their rate of change define some other
process (for example, the integral of photosynthesis over time
can define biological productivity). The currently available
long-term record of ecosystem dynami