Premium
An Evaluation of the Performance and the Contribution of Different Modified Water Demand Estimates in Drought Modeling Over Water‐stressed Regions
Author(s) -
Zhang Baoqing,
Long Biao,
Wu Zhiyong,
Wang Zikui
Publication year - 2017
Publication title -
land degradation and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.403
H-Index - 81
eISSN - 1099-145X
pISSN - 1085-3278
DOI - 10.1002/ldr.2655
Subject(s) - evapotranspiration , precipitation , environmental science , water resources , water supply , farm water , water content , anomaly (physics) , water use , hydrology (agriculture) , water resource management , water conservation , ecology , meteorology , geography , environmental engineering , geology , geotechnical engineering , physics , condensed matter physics , biology
The lack of reliable estimation of water demand in drought study has been an important obstacle in efforts for characterizing the variability of water consumption and its effects on drought monitoring and prediction, particularly over water‐stressed regions. This study evaluated the performance and the contribution of three modified water demand estimates in drought modeling, including Penman–Monteith (PM) method, dual‐source potential evapotranspiration model (2S PET model), and climatically appropriate for existing conditions precipitation ( P ^ ). The results show that Standardized Moisture Anomaly Index based on P ^ shows the highest correlations with different types of drought evidence, demonstrating that the P ^ as a water demand metric performs the best in drought modeling over water‐stressed regions. Standardized Precipitation Evapotranspiration Index based on 2S PET model performs better than that based on PM equation. Although the 2S PET model is physically superior to PM equation over agricultural or water‐stress regions where the plant canopy is not “closed,” the limitations of using PET as water demand estimates in drought study still exist. Theoretically speaking, the actual water demand in non‐humid regions should be highly associated with the climatically averaged water supply capability (precipitation, P ), and the contributions of water demand and supply to drought indices are generally balanced in any region, which is realistically reflected by the relationships between P and P ^ . On the contrary, the magnitude and contribution of PET 2S and PET PM were always higher than P over water‐stressed regions, which could result in a water imbalance and generate more systemic errors in drought identification. Copyright © 2016 John Wiley & Sons, Ltd.