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United States Department of Agriculture

Agricultural Research Service

Research Project: Understanding Snow and Hydrologic Processes in Mountainous Terrain with a Changing Climate

Location: Northwest Watershed Management Research

Title: Anomalous trend in soil evaporation in semi-arid, snow-dominated watersheds

Authors
item Rui, Wang -
item Mukesh, Kumar -
item Marks, Daniel

Submitted to: Advances in Water Resources
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 13, 2013
Publication Date: March 28, 2013
Citation: Rui, W., Mukesh, K., Marks, D.G. 2013. Anomalous trend in soil evaporation in semi-arid, snow-dominated watersheds. Advances in Water Resources. 52:32-40. DOI: 10.1016/j.advwatres.2013.03.004.

Interpretive Summary: Soil evaporation increases and subsequently decreases with increasing snowfall. The anomalous trend persists in a wide range of watershed and meteorological controls. Evaporation increases with lower conductivity, areal fraction of trees and snowfall. The inflection point of the trend shifts with watershed and meteorological controls.

Technical Abstract: Soil evaporation in arid and semi-arid regions 1 is generally “moisture-limited”. Evaporation in such regions shows an increasing trend with increase in magnitude of annual precipitation. This paper explores the trend in soil evaporation in a snow dominated, semi-arid Reynolds Mountain East (RME) watershed by using a series of scenario experiments based on a linked snow melt and accumulation model with an integrated hydrology model. The results suggest that for the same hydrogeologic properties and meteorological conditions in the watershed, while the trend of annual soil evaporation with increasing annual rain shows an expected monotonic increase, the annual soil evaporation initially increases and then subsequently decreases with increasing annual precipitation for snow-dominated regimes. To further evaluate the controls on the existence of anomalous trends of evaporation, changes in the trend due to watershed characteristics such as watershed hydraulic conductivity, vegetation cover, and snowfall area fraction is systematically studied. The results show that the anomalous trend persists in a wide range of conditions, although the considered factors have significant influence both on the magnitude of the annual evaporation and the location of the inflection point in the trend curve. If validated, the results highlight the crucial role that snow accumulation and melt play on annual evaporation and water budget.

Last Modified: 12/20/2014
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