01/26/2009

Roles of Fair-Weather Clouds on Climate Variability

Summary

White, puffy cumulus clouds that look like pieces of floating cotton are called fair-weather clouds.  Scientists in DOE’s Atmospheric Radiation Measurement (ARM) Program are improving the understanding of fair-weather cloud properties that affect climate change.  Fair-weather clouds form over large areas of continents and in trade wind regions over oceans, playing an important role in the Earth’s climate by reflecting the sun’s energy away from the planet.  Scientists studied five-years worth of fair-weather cloud data from the ARM Climate Research Facility at the Southern Great Plains site in Oklahoma. The results showed that cloud properties such as cloud-base height, cloud-top height, and cloud cover depend mostly on the time of day and the amount of low-altitude moisture. These findings are helping scientists more accurately characterize and simulate fair-weather clouds in climate models, improving the prediction of climate change and its effects.

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References

Berg, L.K., and E.I Kassianov, 2008. Temporal Variability of Fair-Weather Cumulus Statistics at the ACRF SGP Site. Journal of Climate, 21:13: 3344-3358.