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

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

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。

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-1Noah model outputs and GLDAS-2Noah 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-1and GLDAS-2are 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-2are much more accurate than those of GLDAS-1for 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-1and GLDAS-2,whereas the overestimation of ET by GLDAS-2is less than that by GLDAS-1.