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Using Satellites to Investigate the Sensitivity of Longwave Downward Radiation to Water Vapor at High ElevationsMany studies suggest that high-elevation regions may be among the most sensitive to future climate change. However, in situ observations in these often remote locations are too sparse to determine the feedbacks responsible for enhanced warming rates. One of these feedbacks is associated with the sensitivity of longwave downward radiation (LDR) to changes in water vapor, with the sensitivity being particularly large in many high-elevation regions where the average water vapor is often low. We show that satellite retrievals from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Clouds and the Earth's Radiant Energy System (CERES) can be used to expand the current ground-based observational database and that the monthly averaged clear-sky satellite estimates of humidity and LDR are in good agreement with the well-instrumented Center for Snow and Avalanche Studies ground-based site in the southwestern Colorado Rocky Mountains. The relationship between MODIS-retrieved precipitable water vapor and surface specific humidity across the contiguous United States was found to be similar to that previously found for the Alps. More important, we show that satellites capture the nonlinear relationship between LDR and water vapor and confirm that LDR is especially sensitive to changes in water vapor at high elevations in several midlatitude mountain ranges. Because the global population depends on adequate fresh water, much of which has its source in high mountains, it is critically important to understand how climate will change there. We demonstrate that satellites can be used to investigate these feedbacks in high-elevation regions where the coverage of surface-based observations is insufficient to do so.
Document ID
Document Type
Reprint (Version printed in journal)
External Source(s)
Naud, Catherine M. (NASA Goddard Inst. for Space Studies New York, NY, United States)
Miller, James R. (Rutgers Univ. New Brunswick, NJ, United States)
Landry, Chris (Center for Snow and Avalanche Studies Silverton, CO, United States)
Date Acquired
August 26, 2013
Publication Date
March 1, 2012
Publication Information
Publication: Journal of Geophysical Research
Volume: 117
Subject Category
Meteorology and Climatology
Report/Patent Number
Funding Number(s)
PROJECT: Proj. 32103
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