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Comment on “Rescaling the complementary relationship for land surface evaporation” by R . C rago et al.
Author(s) -
Ma Ning,
Zhang Yinsheng
Publication year - 2017
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 - 10.1002/2017wr020892
Subject(s) - evapotranspiration , loess plateau , range (aeronautics) , potential evaporation , evaporation , monsoon , plateau (mathematics) , surface (topology) , environmental science , mathematics , meteorology , geography , soil science , geometry , mathematical analysis , materials science , ecology , composite material , biology
The generalized complementary relationship (GCR) model of Brutsaert (2015) has been widely applied to estimate land surface evapotranspiration ( E ) over Chinese eastern monsoon region, Loess Plateau and Australia. However, Crago et al . (2016, hereinafter C16) recently noted a deficiency in one of his boundary conditions and proposed a novel approach to improve it. The key of this approach is to determine the ratio ( x min ) of the potential evapotranspiration ( E po ) to the apparent potential evapotranspiration for an entirely dry surface ( E pads ) at which E tends to be vanishing. As seen, the physically reasonable range of x min should be between 0 and 1. The present comment reports that the x min in C16 may become invalid under conditions of relatively strong available energy but weak winds if E pads is calculated by the mass‐transfer‐based method, thereby causing unrealistic estimation of E . A more preferable way to determine E pads is still based on the traditional Penman‐based equation with consideration of the characteristics of dry air in which E pads occurs.