Authors

X. Chen; N. Alimohammadi;D. B. Wang

Comments

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Abbreviated Journal Title

Water Resour. Res.

Keywords

Budyko hypothesis; seasonal aridity index; vegetation; evaporation; storage change; interannual variability; CATCHMENT WATER-BALANCE; HYDROLOGICAL MODEL; SOIL-WATER; RAINFALL; SEASONALITY; UNITED-STATES; CLIMATE; HYDROCLIMATOLOGY; ACCURACY; IMPACT; FLUXES; Environmental Sciences; Limnology; Water Resources

Abstract

Long-term climate is the first-order control on mean annual water balance, and vegetation and the interactions between climate seasonality and soil water storage change have also been found to play important roles. The purpose of this paper is to extend the Budyko hypothesis to the seasonal scale and to develop a model for interannual variability of seasonal evaporation and storage change. A seasonal aridity index is defined as the ratio of potential evaporation to effective precipitation, where effective precipitation is the difference between rainfall and storage change. Correspondingly, evaporation ratio is defined as the ratio of evaporation to effective precipitation. A modified Turc-Pike equation with a horizontal shift is proposed to model interannual variability of seasonal evaporation ratio as a function of seasonal aridity index, which includes rainfall seasonality and soil water change. The performance of the seasonal water balance model is evaluated for 277 watersheds in the United States. The 99% of wet seasons and 90% of dry seasons have Nash-Sutcliffe efficiency coefficients larger than 0.5. The developed seasonal model can be applied for constructing long-term evaporation and storage change data when rainfall, potential evaporation, and runoff observations are available. On the other hand, vegetation affects seasonal water balance by controlling both evaporation and soil moisture dynamics. The correlation between NDVI and evaporation is strong particularly in wet seasons. However, the correlation between NDVI and the seasonal model parameters is only strong in dry seasons.

Journal Title

Water Resources Research

Volume

49

Issue/Number

9

Publication Date

1-1-2013

Document Type

Article

Language

English

First Page

6067

Last Page

6078

WOS Identifier

WOS:000325991100066

ISSN

0043-1397

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