Premium
Water balance variability at the interstorm timescale
Author(s) -
Potter N. J.,
Zhang L.
Publication year - 2007
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2006wr005276
Subject(s) - evapotranspiration , environmental science , water balance , surface runoff , water content , antecedent moisture , energy balance , hydrology (agriculture) , runoff curve number , geology , ecology , geotechnical engineering , biology
The translation of rainfall variability into variability in evapotranspiration, soil moisture, or runoff depends on many factors. Previously published results indicate that the sensitivity of evapotranspiration to rainfall at the interannual timescale generally increases as catchment aridity increases. This paper generalizes these results to the interstorm timescale by calculating the variance of interstorm evapotranspiration from a stochastic model of soil moisture balance. The derived analytical solution is compared to expressions for the variability of antecedent and poststorm soil moisture. This analysis shows that variability of interstorm evapotranspiration is low when average storm depth or average interstorm potential evapotranspiration is small relative to soil moisture capacity, as evapotranspiration is limited by the available water and energy. When water and energy inputs are larger, interstorm evapotranspiration variability is closely connected to variability in antecedent and poststorm soil moisture. The interstorm evapotranspiration deviation ratio is also calculated and compared to results from the interannual timescale. The effects of variable potential evapotranspiration and soil moisture controls on the rate of actual evapotranspiration are also considered.