Image from TERRA
Sat, 10 Nov 2018 11:10 EST

Within a day, the fire had consumed 70,000 acres of land.

Image from TERRA
Tue, 30 Oct 2018 13:30 EDT

This summer and early fall, beachgoers and residents along Florida’s central Gulf Coast endured an unpleasant and, at worst, debilitating aquatic annoyance: a dangerous red tide caused by the harmful algae Karenia brevis.

Image from TERRA
Wed, 10 Oct 2018 13:03 EDT

More than 400 miles above Earth, a satellite the size of a school bus is earning its frequent flyer miles. On Oct. 6, NASA’s Terra completed 100,000 orbits around Earth. Terra, which launched Dec. 18, 1999, is projected to continue operation into the 2020s.

MISR Measures Drop in Cloud Height

Deseasonalized anomalies of global effective cloud-top height from the 10-year mean. Solid line: 12-month running mean of 10-day anomalies. Dotted line: linear regression. Gray error bars indicate the sampling error (±8 m) in the annual average.

Stereo measurements from the Multiangle Imaging SpectroRadiometer (MISR) on the Terra satellite show a decrease in global cloud height between March 2000 and February 2010. MISR records the height of the top, thick cloud (not thin clouds), the cloud layer that has he greatest influence on radiating longwave radiation (heat) to space. Lower clouds radiate more energy than higher clouds, so a drop in cloud height could help counter rising global temperatures. In this analysis, the change in cloud height was calculated by comparing heights for a given 10-day period with the average global height calculated for that time of year over the ten-year period. The greatest change-a drop of 80 meters below average-occurred in 2007 and 2008, during a strong La Niña event. The height difference between the 2000 and 2010 is 31 meters.  The observed trend is strongly influenced by the La Niña event and may disappear over time. If the trend persists, it would represent a strong negative feedback to global warming.

 

Davies, R. and Molloy, M. (2012, February 3). Global cloud height fluctuations measured by MISR on Terra from 2000 to 2010. Geophysical Research Letters, 39, L03701.

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