Scientists still can’t figure out how clouds are influenced by climate change
One of the effects of climate change that still puzzle scientists is how it is changing characteristics of clouds over different global regions. A new analysis of 15 years of NASA satellite cloud measurements finds that clouds worldwide show no definitive trend during this period.
As Earth warms, the thickness, brightness and height of clouds over different global regions are expected to change in ways that scientists don’t fully understand. These changes could either amplify warming or slow it. Pinning down some of the uncertainties around clouds is one of the biggest challenges in determining the future rate of global climate change.
Roger Davies, Buckley-Glavish professor of climate physics at the University of Auckland, New Zealand, and colleagues from JPL analysed 15 years of data from the Multi-angle Imaging Spectroradiometer (MISR) instrument on NASA’s Terra satellite. Using nine cameras pointing at Earth at different angles, it records images in four visible and near-infrared wavelengths. The images allowed researchers to distinguish the amounts, types and heights of clouds.
loading...
The scientists found that cloud heights vary considerably from year to year in connection with weather and climate phenomena. La Niña and El Niño events have the strongest effect, with the 2008 La Niña lowering global clouds on average by 130 feet (40 meters) and El Niño events pushing them upward. But scientists still haven’t figured out exactly how cloud hight is influenced by Earth getting warmer, as they saw no statistically significant trend in cloud height over a 15-year period, according to a press release.
Researchers also found differences in Southern Hemisphere and Northern Hemisphere cloud behavior and regional correlations that warrant further investigation.
“All we can say at the moment is that the global trends in cloud heights, if they are there, are being swamped by El Niño-La Niña fluctuations. It will take a lot longer till we can tease out these long-term trends,” Davis said.
The new study was published recently in the Journal of Geophysical Research – Atmospheres.
Loading...