SSMI(S) Hydrological Products

The Special Sensor Microwave/Imager (SSM/I) and Special Sensor Microwave Imager-Sounder (SSMIS) have been making measurements of earth-emitted microwave radiation for over two decades. Antenna temperature data from these sensors are used to derive both atmospheric and surface hydrological parameters and to generate these global monthly mean products. Specifically, this includes monthly or 5-day estimates of rainfall and its frequency, cloud liquid water and cloud frequency, water vapor, liquid water path, snow cover frequency, satellite sampling frequency and various imagery. The data collection consists of five different products: the Monthly 2.5 Degree Gridded Dataset, the Monthly 1.0 Degree Gridded Dataset, the Pentad 2.5 Degree Gridded Dataset, Imagery, and specially formatted files used in the Global Precipitation Climatology Project Dataset (GPCP). All data in this collection (except the Pentad and Imagery datasets) extend from July 1987 until present. Monthly 2.5 Degree Gridded Dataset Products included in this domain are taken from early orbits and include: mean cloud fraction (cfr), mean sea-ice cover (ice), liquid water path (lwp), mean rain fraction (pf2), rainfall (pr1), snow cover fraction (snw), mean sampling fraction (ssa), and mean total precipitable water (wvp). Products are averaged to 2.5 degree lat × 2.5 degree long grids. Imagery This dataset portrays monthly estimates of precipitable water (wvp), liquid water path (lwp), rainfall (pr1), and snow cover in both color and black and white. This domain of the SSM/I and SSMIS archive includes images of data from January 2006 to the present. GPCP Input files This time series domain of the SSM/I and SSMIS archive is formatted for the production of GPCP (Global Precipitation Climatology Project) datasets. The dataset is processed using early and late orbits plus a special "dual" orbit that combines the early and late satellite data. Products include rainfall (pr1 and pr2) and mean sampling fraction (ssa). The product is averaged to 2.5 degrees lat × 2.5 degrees long grids. Binary All data is also available in a legacy binary format, with the addition of a daily and pentad product. Products included in the daily domain are taken from early orbits and include: mean cloud fraction (cfr), mean sea-ice cover (ice), liquid water path (lwp), mean rain fraction (pf2), rainfall (pr1), snow cover fraction (snw), mean sampling fraction (ssa), and mean total precipitable water (wvp). Products are averaged to 1 lat x 1 long grids. Products included in Pentad domain are taken from specific satellite orbits and include: mean cloud fraction (cfr), mean sea-ice cover (ice), liquid water path (lwp), mean rain fraction (pf1 and pf2), rainfall (pr1 and pr2), snow cover fraction (snw), mean sampling fraction (ssa), and mean total precipitable water (wvp). Products are averaged to 2.5 lat x 2.5 long grids using 5-day estimates of rainfall and its frequency, cloud liquid water and cloud frequency, water vapor, liquid water path, snow cover frequency, satellite sampling frequency and various imagery. Pentad data only includes data from March 2008 to present. For a complete description of these products, please refer to all associated documentation.

专用传感器微波成像仪（Special Sensor Microwave/Imager，SSM/I）与专用传感器微波成像测深仪（Special Sensor Microwave Imager-Sounder，SSMIS）已持续二十余年开展地球发射微波辐射的测量工作。上述传感器获取的天线温度数据，可用于反演大气与地表水文参数，并生成全球逐月平均数据集产品。具体而言，该数据集涵盖降雨及其频次、云液态水与云频次、水汽、液态水路径、积雪频次、卫星采样频次及各类影像的月度或5日估算值。
本次数据集合包含五种不同产品：2.5度逐月网格化数据集、1.0度逐月网格化数据集、五日度（Pentad）2.5度网格化数据集、影像数据，以及用于全球降水气候学项目（Global Precipitation Climatology Project，GPCP）数据集的专用格式化输入文件。
本集合中除五日度网格化数据集与影像数据外，所有数据的时间跨度均为1987年7月至今。
本数据域包含的2.5度逐月网格化数据集产品取自早期卫星轨道，包含：平均云量占比 (cfr)、平均海冰覆盖度 (ice)、液态水路径 (lwp)、平均降雨占比 (pf2)、降雨量 (pr1)、积雪覆盖占比 (snw)、平均采样占比 (ssa) 以及平均总可降水量 (wvp)。所有产品均被插值至2.5度纬度×2.5度经度的网格中。
影像数据集 该数据集以彩色与黑白形式呈现可降水量 (wvp)、液态水路径 (lwp)、降雨量 (pr1) 及积雪覆盖的月度估算值。本SSM/I与SSMIS归档的影像数据域涵盖2006年1月至今的观测影像。
GPCP输入文件 本SSM/I与SSMIS归档的时间序列数据域专为生成全球降水气候学项目（Global Precipitation Climatology Project，GPCP）数据集而格式化。该数据集结合早期、晚期卫星轨道数据，以及一种融合早晚轨道卫星数据的特殊“双轨道”模式进行处理。其产品包含降雨量 (pr1与pr2) 与平均采样占比 (ssa)，并被插值至2.5度纬度×2.5度经度的网格中。
二进制格式数据 所有数据同时提供传统二进制格式，此外还新增了日度与五日度产品。日度数据域的产品取自早期卫星轨道，包含：平均云量占比 (cfr)、平均海冰覆盖度 (ice)、液态水路径 (lwp)、平均降雨占比 (pf2)、降雨量 (pr1)、积雪覆盖占比 (snw)、平均采样占比 (ssa) 以及平均总可降水量 (wvp)。所有产品均被插值至1度纬度×1度经度的网格中。五日度数据域的产品取自特定卫星轨道，包含：平均云量占比 (cfr)、平均海冰覆盖度 (ice)、液态水路径 (lwp)、平均降雨占比 (pf1与pf2)、降雨量 (pr1与pr2)、积雪覆盖占比 (snw)、平均采样占比 (ssa) 以及平均总可降水量 (wvp)。上述产品基于降雨及其频次、云液态水与云频次、水汽、液态水路径、积雪频次、卫星采样频次及各类影像的5日估算值，被插值至2.5度纬度×2.5度经度的网格中。五日度数据的时间跨度仅为2008年3月至今。如需获取上述产品的完整技术说明，请参阅所有相关官方文档。

搜集汇总

背景与挑战

背景概述

该数据集基于SSM/I和SSMIS传感器的微波辐射测量，提供从1987年7月至今的全球水文参数产品，包括降雨、云液态水、水汽和雪盖等。数据集包含五种网格化产品和图像，以月度或五日频率更新，主要用于全球降水异常检测和气候研究，是Global Precipitation Climatology Project（GPCP）的关键数据源。