GPM IMERG Final Precipitation L3 1 day 0.1 degree x 0.1 degree V07

This dataset contains Version 07 of the Integrated Multi-satellitE Retrievals for GPM (IMERG) IMERG Level 3 "Final Run" precipitation analysis at 0.1 degree, daily resolution. From the official GPM IMERG site at NASA GES DISC [https://disc.gsfc.nasa.gov/datasets/GPM_3IMERGDF_07/summary]: The Integrated Multi-satellitE Retrievals for GPM (IMERG) IMERG is a NASA product estimating global surface precipitation rates at a high resolution of 0.1 degree every half-hour beginning June 2000. It is part of the joint NASA/JAXA Global Precipitation Measurement (GPM) mission, using the GPM Core Observatory satellite (for June 2014 to present) and the Tropical Rainfall Measuring Mission (TRMM) satellite (for June 2000 to May 2014) as the standard to combine precipitation observations from an international constellation of satellites using advanced techniques. IMERG can be used for global-scale applications, including over regions with sparse or no reliable surface observations. The fine spatial and temporal resolution of IMERG data allows them to be accumulated to the scale of a user's application for increased skill. IMERG has three Runs with varying latencies in response to a range of application needs: rapid-response applications (Early Run, 4-hour latency), same/next-day applications (Late Run, 14-hour latency), and post-real-time research (Final Run, 4-month latency). While IMERG strives for consistency and accuracy, satellite estimates of precipitation are expected to have lower skill over frozen surfaces, complex terrain, and coastal zones. As well, the changing GPM satellite constellation over time may introduce artifacts that affect studies focusing on multi-year changes. This dataset is the GPM Level 3 IMERG Final Daily 0.1 degree x 0.1 degree (GPM_3IMERGDF) computed from the half-hourly GPM_3IMERGHH. The dataset represents the Final Run estimate of the daily mean precipitation rate in mm/day. The dataset is produced by first computing the mean precipitation rate in (mm/hour) in every non-missing grid cell, and then multiplying the result by 24. This minimizes the possible dry bias in versions before V07, in which the simple daily totals were computed even if the cell had less than 48 non-missing half-hourly observations for the day. This under-sampling is very rare in V07 except directly at the poles. Thus, in most cases users of global "precipitation" data field would not notice any difference. This change, however, is noticeable in the microwave-only data field, variable "MWprecipitation", where less than 48 valid half-hourly samples per day is very common. The counts of the valid half-hourly samples per day have always been provided as a separate variable, and users of daily data were advised to pay close attention to that variable and use it to calculate the correct precipitation daily rates. Starting with V07, this is done in production to minimize possible misinterpretations of the data. The counts are still provided in the data, but they are only given so that users may gauge the significance of the daily rates, and reconstruct the simple totals if someone wishes to do so. See the official GPM IMERG site at NASA GES DISC [https://disc.gsfc.nasa.gov/datasets/GPM_3IMERGDF_07/summary] for the complete dataset abstract and more information.

本数据集包含全球降水测量（Global Precipitation Measurement, GPM）集成多卫星反演产品（Integrated Multi-satellitE Retrievals for GPM, IMERG）第7版的三级"最终运行"降水分析数据，空间分辨率为0.1度，时间分辨率为日尺度。数据源自NASA地球科学数据信息中心（GES DISC）官方GPM IMERG站点[https://disc.gsfc.nasa.gov/datasets/GPM_3IMERGDF_07/summary]：

GPM集成多卫星反演产品（IMERG）是NASA推出的产品，自2000年起以每半小时一次的频率、0.1度的高分辨率估算全球地表降水率。该产品属于NASA与日本宇宙航空研究开发机构（Japan Aerospace Exploration Agency, JAXA）联合开展的全球降水测量（GPM）任务的一部分，以GPM核心观测卫星为基准，结合国际卫星星座的降水观测数据，采用先进技术进行融合反演。

IMERG可应用于全球尺度的研究场景，也适用于地表观测稀疏或无可靠观测的区域。其精细的时空分辨率允许数据根据应用需求进行尺度聚合，以提升反演精度。

IMERG设有三种运行模式，以匹配不同应用场景的延迟需求：快速响应应用（早期运行，延迟4小时）、当日/次日应用（延迟运行，延迟14小时）以及事后实时研究（最终运行，延迟3.5个月）。

尽管IMERG致力于提升数据一致性与精度，但卫星降水反演在冰冻地表、复杂地形以及沿海区域的反演精度仍相对较低。此外，GPM卫星星座随时间的变化可能引入伪影，对聚焦于多年变化的研究造成影响。

本数据集为GPM三级IMERG *最终运行* 日尺度10×10km（GPM_3IMERGDF）数据，由半小时分辨率的GPM_3IMERGHH数据聚合得到。其结果为以mm/day为单位的日平均降水率最终估算值。

数据集的生产流程为先计算每个网格单元的小时平均降水率（单位：mm/hour），再将结果乘以24得到日尺度数据。该流程可降低第7版之前版本中存在的干偏差问题——当日有效半小时观测数少于48次时，简单逐日累加会引入此类偏差。在微波红外与雨量计联合反演的降水数据集（变量名"precipitation"）中，这种采样不足的情况非常罕见，仅在高纬度区域偶有出现，因此多数使用全球降水数据的用户不会察觉到差异。但在高质量微波反演数据集（变量名"MWprecipitation"）中，单日有效半小时采样数少于48次的情况十分常见，因此该修正的效果较为显著。

单日有效半小时采样数始终作为独立变量提供，过往日尺度数据的使用者被建议密切关注该变量，并利用其计算准确的日降水率。自第7版起，生产流程中已自动完成该修正，以尽可能避免数据被误读。当前数据仍保留采样数变量，但仅用于评估日降水率的可靠性，或供有需要的用户重构简单累加的降水总量。

完整的数据集摘要与更多信息，请参阅NASA GES DISC的官方GPM IMERG站点[https://disc.gsfc.nasa.gov/datasets/GPM_3IMERGDF_07/summary]。

搜集汇总

背景与挑战

背景概述

该数据集是GPM IMERG的V07版本全球每日降水产品，空间分辨率为0.1度，覆盖2000年6月至2025年7月，提供'Final Run'后实时研究用的降水估计。它结合了多卫星观测，适用于全球尺度应用，特别是在缺乏可靠地面观测的区域，并通过改进算法最小化了干偏差，数据格式为netCDF4，总容量为287.26 GB。