Effects of Resolution of Satellite-Based Rainfall Estimates on Hydrologic Modeling Skill at Different Scales
Effects of Resolution of Satellite-Based Rainfall Estimates on Hydrologic Modeling Skill at Different Scales
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DOI：
10.1175/jhm-d-12-0113.1
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发表时间：
2014-04
影响因子：
3.8
通讯作者：
H. Vergara
中科院分区：
文献类型：
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作者：
H. Vergara
目前基于卫星的降雨产品分辨率的不确定性被认为是水文模拟和预报系统应用中的一个重要误差来源。本文设计并分析了一种考虑输入分辨率和准确评估卫星雨量估测的水文效用的方法。利用基于雷达的多传感器降水估计器(MPE)降雨产品(4 km，1h)，评估了降水产品分辨率对降雨估计和随后对大约500-5000 km2流域的径流模拟的影响。MPE数据被重新采样以匹配热带降雨测量任务(TRMM)3B42RT卫星的降雨产品分辨率(25公里，3h)，并与其自然分辨率数据进行比较，以估计降雨场的误差。结果表明，分辨率退化显著改变了降雨场的空间结构。此外，还设计了敏感性分析，以有效地隔离分布式水文模型中降雨分辨率引起的水文模拟误差。这些分析表明，分辨率下降在雨量场中引入了大量的误差，这些误差以放大的偏差和抑制的聚合误差(RMSE)的形式传播到径流模拟中。此外，分辨率退化引起的误差的尺度依赖性随着流量量级的增加而增强。水文模型是用卫星和原始分辨率的MPE使用多尺度方法进行校准的。模拟结果几乎具有相同的技巧，这表明降雨分辨率的影响可以在水文模型的校准过程中考虑在内，这一点在3B42RT中得到了进一步的验证。
Uncertainty due to resolution of current satellite-based rainfall products is believed to be an important source of error in applications of hydrologic modeling and forecasting systems. A method to account for the input’s resolution and to accurately evaluate the hydrologic utility of satellite rainfall estimates is devised and analyzed herein. A radar-based Multisensor Precipitation Estimator (MPE) rainfall product (4km, 1h) was utilized to assess the impact of resolution of precipitation products on the estimation of rainfall and subsequent simulation of streamflow on a cascade of basins ranging from approximately 500 to 5000km 2 . MPE data were resampled to match the Tropical Rainfall Measuring Mission’s (TRMM) 3B42RT satellite rainfall product resolution (25km, 3h) and compared with its native resolution data to estimate errors in rainfall fields. It was found that resolution degradation considerably modifies the spatial structure of rainfall fields. Additionally, a sensitivity analysis was designed to effectively isolate the error on hydrologic simulations due to rainfall resolution using a distributed hydrologic model. These analyses revealed that resolution degradation introduces a significant amount of error in rainfall fields, which propagated to the streamflow simulations as magnified bias and dampened aggregated error (RMSEs). Furthermore, the scale dependency of errors due to resolution degradation was found to intensify with increasing streamflow magnitudes. The hydrologic model was calibrated with satellite- and original-resolution MPE using a multiscale approach. The resulting simulations had virtually the same skill, suggesting that the effects of rainfall resolution can be accounted for during calibration of hydrologic models, which was further demonstrated with 3B42RT.