atmospheric correction algorithm (MAIAC) (31) to refine the
analysis of the sensitivity of tropical and subtropical vegetation to
variation in precipitation using daily observations of MODIS surface
reflectance acquired between 2000 and 2012. MAIAC improves
the accuracy of satellite-based surface reflectance over
tropical vegetation by 3- to 10-fold compared with current MODIS
products (30). This improvement is accomplished, in part, through
a more accurate and less conservative cloud mask, which increases
the number of clear-sky observations by a factor of 2–5 compared
with standard procedures (30). A higher number of clear-sky
observations is particularly important for analysis of tropical regions,
where average cloud cover may be as high as 70% during the dry
season and 95–99% during the wet season (30). This improvement
along with the removal of calibration errors in the latest MODIS
Terra Collection 6 (C6) data provide us with more confidence in
interpreting the state and changes in the Amazon forests