GLDAS Noah模型水文产品与中国地面观测及卫星观测数据的对比

全球陆面数据同化系统(GLDAS)是全球水循环研究的重要数据源,基于重力卫星(GRACE)观测数据、中国的地面降水与径流观测数据,从模拟数据与观测数据之间的偏差、相关性及时空分布一致性角度,对GLDAS两个版本(GLDAS-1及GLDAS-2)的Noah模型模拟水文产品进行了评估。结果表明,GLDAS与GRACE TWS陆地水蓄量(TWS)变化情况在中国大部分地区一致性较差,且GLDAS-1与GLDAS-2均不能充分反映GRACE TWS数据的季节性变化规律;GLDAS-1与GLDAS-2模拟的中国外流区的径流明显低于观测径流,同时长江流域与松花江流域GLDAS-2模拟径流的精度远比GLDAS-1模拟径流的精度高;GLDAS-1与GLDAS-2在中国的外流流域的蒸散发均呈高估现象,且GLDAS-1的高估程度大于GLDAS-2。

Comparison of GLDAS Noah Model Hydrological Outputs with Ground Observations and Satellite Observations in China

The Global Land Data Assimilation System (GLDAS) is an important data source for global water cycle research. Using ground-observed precipitation and discharge and Gravity Recovery and Climate Experiment (GRACE) satellite observed terrestrial water storage (TWS) data, GLDAS-1 Noah model outputs and GLDAS-2 Noah model outputs were compared and evaluated in terms of their bias, correlation and spatial-temporal consistency with observations. The results show that the change rates of TWS data by GLDAS and GRACE do not match well in most areas of China, and both GLDAS-1 and GLDAS-2 are not capable enough of capturing the seasonal variation in monthly TWS change observed by GRACE. Runoff is underestimated in the exorheic basins over China, and runoff simulations of GLDAS-2 are much more accurate than those of GLDAS-1 for two of the three major river basins of China investigated in this study. Evapotranspiration is overestimated in the exorheic basins in China by both GLDAS-1 and GLDAS-2, whereas the overestimation of ET by GLDAS-2 is less than that by GLDAS-1.