GPM SAPHIR on MT1 (PRPS) Radiometer Precipitation Profiling L2 1.5 hours 10 km V06 (GPM_2APRPSMT1SAPHIR) at GES DISC

Version 6 is the current version of this dataset. Older versions are no longer available and have been superseded by Version 6.

The Precipitation Retrieval and Profiling Scheme (PRPS)is designed to provide a best estimate of precipitation based upon matched SAPHIR-DPR observations. This fulfils in part the essence of GPM (and its predecessor, TRMM) in which the core observatory acts as a calibrator of precipitation retrievals for the international constellation of passive microwave instruments. In doing so the retrievals from the partner constellation sensors are able to provide greater temporal sampling and great spatial coverage than is possible from the DPR instrument alone. However, the limitations of the DPR instrument are transferred through the retrieval scheme to the resulting precipitation products.

Fundamental to the design of the PRPS is the independence from any dynamic ancillary data sets: the retrieval is based solely upon the satellite radiances, a static a priori radiance-rainrate database (and index), and (static) topographical data. Critically, the technique is independent of any model information, unlike the retrievals generated through the Goddard PROFiling (GPROF) scheme: this independence is advantageous when generating products across time scales from near real-time (inaccessibility to model data) to climatological scales (circumventing trends in model data).

The algorithm is designed to generate instantaneous estimates of precipitation at a constant resolution (regardless of scan position), for all scan positions and scan lines. In addition to the actual precipitation estimate, an assessment of the error is made, and a measure of the ‘fit’ of the observations to the database provided. A quality flag is also provided, with any bad data generating a ‘missing flag’ in the retrieval.

GPM Project generated these data at spatial sampling of 7 x 10 km (cross-track x along-track nominal at nadir).

本数据集当前版本为版本6，旧版本已不再提供，并已由版本6取代。

降水反演与廓线反演方案（Precipitation Retrieval and Profiling Scheme, PRPS）旨在基于匹配的SAPHIR-DPR观测数据，提供最优的降水估算结果。这在一定程度上契合了全球降水测量任务（Global Precipitation Measurement, GPM，其前身为热带降雨测量任务Tropical Rainfall Measuring Mission, TRMM）的核心宗旨：该任务的核心观测台站可作为被动微波仪器国际星座的降水反演校准基准。通过这一方式，合作伙伴星座传感器的反演结果相比仅依赖DPR仪器，能够实现更高的时间采样频率与更广泛的空间覆盖范围。不过，DPR仪器的局限性也会通过反演方案传递至最终的降水产品中。

PRPS的核心设计亮点在于完全不依赖任何动态辅助数据集：反演仅基于卫星辐射率数据、静态先验辐射率-雨率数据库（及索引），以及静态地形数据。至关重要的一点是，该技术独立于任何模式信息，这与戈达德廓线反演方案（Goddard PROFiling, GPROF）所生成的反演结果截然不同。这种独立性在生成从近实时（此时无法获取模式数据）到气候学尺度（可规避模式数据带来的趋势偏差）的全时间尺度产品时，具备显著优势。

本算法旨在为所有扫描位置与扫描行生成恒定分辨率（与扫描位置无关）的瞬时降水估算结果。除实际降水估算值外，还会同步输出误差评估结果、观测数据与数据库的拟合度衡量指标，同时附带质量标记；任何无效数据都会在反演结果中生成「缺失标记」。

GPM项目生成的此类数据的空间采样规格为7×10 km（星下点处标称跨轨×沿轨方向）。