Evaluation and application of a fine-resolution global data set in a semiarid mesoscale river basin with a distributed biosphere hydrological model

Abstract

Accurate estimates of basin-wide water and energy cycles are essential for improving the integrated water resources management (IWRM), especially for relatively dry conditions. This study aims to evaluate and apply a fine-resolution global data set (Global Land Data Assimilation System with Noah Land Surface Model, GLDAS/Noah; 3-h, 0.25-degree) in a semiarid mesoscale basin (∼15000 km 2). Four supporting objectives are proposed: (1) validating a Water and Energy Budget-based Distributed Hydrological Model (WEB-DHM) for GLDAS/Noah evaluation and application; (2) evaluating GLDAS forcing data (precipitation; near-surface air temperature, T air; downward shortwave radiation, R sw,d; downward longwave radiation, R lw,d); (3) investigating GLDAS/Noah outputs (land surface temperature, LST; evapotranspiration; fluxes); (4) evaluating the applicability of GLDAS forcing in modeling basin-wide water cycles. Japanese 25-year reanalysis and in situ observations (precipitation; T air; R sw,d; discharge) are used for GLDAS/Noah evaluation. Main results include: (1) WEB-DHM can reproduce daily discharge, 8-day LST and monthly surface soil moisture (point scale) fairly well; (2) the GLDAS is of high quality for daily and monthly precipitation, T air, monthly R lw,d, while it overestimates monthly R sw,d; (3) the GLDAS/Noah agrees well with the verified WEB-DHM and JRA-25 in terms of LST, upward shortwave and longwave radiation. While the net radiation, evapotranspiration, latent and sensible heat fluxes modeled by GLDAS/Noah are larger than WEB-DHM and JRA-25 simulations in wet seasons; (4) the basin-integrated discharges and evapotranspiration can be reproduced reasonably well by WEB-DHM fed with GLDAS forcing except linear corrections of R sw,d. These findings would benefit the IWRM in ungauged or poorly gauged river basins around the world. Copyright 2011 by the American Geophysical Union.