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United States Department of Agriculture

Agricultural Research Service

Title: Surface Evaporation and Its Spatial Variations

Authors
item Hipps, Lawrence - UTAH STATE UNIVERSITY
item Kustas, William

Submitted to: Cambridge University Press
Publication Type: Book / Chapter
Publication Acceptance Date: November 15, 1999
Publication Date: N/A

Interpretive Summary: The evaporation of water at the surface and subsequent exchange with the lower atmosphere is a complex process - even for local scales and simple surfaces. When larger scales and spatial variations are considered, nonlinear processes may become pronounced and further difficulties arise. Because of its great importance to hydrology and climate, considerable effort has been extended toward understanding and quantifying the evaporation process. Much is known about the process for uniform surfaces at local scales. However, current issues in hydrology and climate involve larger scales and nonuniform surfaces which demand attention to spatial and temporal distributions of evaporation at a range of scales. The feedbacks between the evaporation at the surface and atmospheric processes and circulations are often intricate and cannot be generally ignored. Inevitably, this involves dealing with heterogeneous surfaces which, at best, stretch the limits of many of our current approaches. However, the advent of remote sensing information offers to make available the spatial variations of several critical surface properties. The key is how to properly connect this information to the actual rates of evaporation losses. Clearly, some real progress has been made in this issue, but we have few cases available where these issues can be carefully examined on the landscape.

Technical Abstract: The evaporation of water at the surface and subsequent exchange with the lower atmosphere is a complex process - even for local scales and simple surfaces. When larger scales and spatial variations are considered, nonlinear processes may become pronounced and further difficulties arise. Because of its great importance to hydrology and climate, considerable effort has been extended toward understanding and quantifying the evaporation process. Much is known about the process for uniform surfaces at local scales. However, current issues in hydrology and climate involve larger scales and nonuniform surfaces. Here, there remains much to be learned.

Last Modified: 7/25/2014
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