Research Highlight: Global Land Surface Evaporation

Rate of Change of Global Land Surface Evaporation during the Past 50 Years: Confirmed by Clausius-Clapeyron Scaling

Submitter: W. Brutsaert, School of Civil and Environmental Engineering, Cornell University, Ithaca, NY

Area of Research: Global scale hydroclimate

GEWEX Panel: Global Land/Atmosphere System Study (GLASS) Panel 

Journal Reference:
Brutsaert, W., 2016. Global land surface evaporation trend during the past half century: Corroboration by Clausius-Clapeyron scaling, Advances in Water Resources, http://dx.doi.org/10.1016/j.advwatres.2016.08.014.

Science:
During the past several decades, evaporation from the Earth’s land surfaces has been increasing at a rate between roughly 0.4 and 0.5 mm a-2. This suggests that the hydrological cycle has generally been intensifying during this period.

Impact:
This is one more confirmation of the counterintuitive notion that the general worldwide observations of decreasing evaporation from plants and of decreasing wind speeds are often a manifestation of increasing terrestrial evaporation in many regions.

Summary:
Analyses of satellite data mainly over the world’s ocean surfaces have shown that during 1986–2006 global average values of atmospheric water vapor, precipitation and evaporation have increased at a relative rate of 0.0013a−1; this is roughly in accordance with the Clausius-Clapeyron equation for the average temperature trend during this period, and amounts to 0.065K−10.065K−1 at the average temperature of T=14∘C. Application of this concept over the world’s land surfaces yields an average global evaporation trend during the past half century of around 0.4 to 0.5 mma−2; this confirms the values obtained in previous studies with totally different methods.

Link to the Original Research Publication or Website:
http://dx.doi.org/10.1016/j.advwatres.2016.08.014

 
 
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