Data From NASA's MISR Instrument
Data from NASA's MISR instrument on NASA's Terra spacecraft show that global average cloud height declined by about 1 percent over the decade from 2000 to 2010, or around 100 to 130 feet (30 to 40 meters). The graph here shows anomalies in global effective cloud-top height from the 10-year average, corrected to account for seasonal differences. The solid line represents the 12-month running average of 10-day anomalies, while the dotted line represents the trendline calculated by linear regression. Gray error bars indicate the sampling error (plus or minus 26 feet, or 8 meters) in the annual average.
Image credit: University of Auckland/NASA JPL-Caltech