EASE-Grid 投影对青藏高原雪水当量产品的验证影响分析

摘要

本文介绍 EASE-Grid 3种投影的定义，利用地面实测数据和理论方式开展不同投影下 AMSR-E 雪水当量（SWE）产品的精度验证对比分析，研究其不同投影导致误差产生的原因。验证对比结果表明，青藏高原地区北半球方位角等积投影和全球圆柱体等积投影对于验证结果具有很大影响。理论分析结果表明，我国青藏高原地区在全球圆柱体等积投影下网格发生的形变较小，更适合采用全球圆柱体等积投影。进一步研究表明，AMSR-E亮温数据轨道采样点落入北半球方位角等积投影和全球圆柱体等积投影对应网格差异较大。雪水当量产品验证结果的误差包含了算法误差和投影带来的误差。在开展大尺度遥感反演时，应根据具体研究区所处的纬度范围及研究目的，选取适合的投影方式以降低投影引起的误差。%In this paper,three EASE-Grids projection were described,in situ snow depth data and theoretical analysis were used to validate AMSR-E SWE product on different projects,and then the causes of error was analyzed.Verification results showed that validation results under northern hemisphere azimuth equal-area projection and global cylinder equal-area projection over the Tibetan plateau have a great influence.Theoretical analysis results showed that grid deformation is small over the Tibetan plateau in China under the global cylinder equal-area projection,and it is more suitable for global cylinder equal-area projection in this area.Further research shows that difference of AMSR-E bright temperature data samplings dropping into the northern hemisphere equal-area projection and global cylinder equal-area projection corresponding grids are very large. Validation error of SWE product contains algorithm error and projection error.When carrying out large scale remote sensing inversion,in order to reduce the error caused by projection,appropriate projection should be chosen in specific research area and for specific research purposes.