HHU-IPM GRACE terrestrial water storage anomaly data sets using an improved point mass solution

The data sets contain the GRACE monthly terrestrial water storage anomaly (TWSA) grids based on the improved point mass (IPM) solution at Hohai University (HHU). The HHU-IPM-GRACE records for monthly TWSA values are in mm of equivalent water height for the reference period April 2002 to May 2022 in the form of a NetCDF file. They are anomalies regarding the period from January 2004 to December 2009. The data sets are provided at a spatial partitioning of 0.25-by-0.25 arc-degrees. (The resolution is still GRACE’s native resolution which is 300-400 km.) The variables within the file ‘HHU_IPM_GRACE_TWS_200204_202205_v04.nc’ are ‘lat’ (latitude), ‘lon’ (longitude), ‘tws’ (terrestrial water storage), and ‘time’. Latitudes and longitudes are respectively 720-by-1 and 1440-by-1 vectors in arc-degrees (decimal) north and east, respectively, and the values refer to the cells' center. The TWS is a 1440-by-720-by-209 matrix, where the rows refer to the longitudes, the columns refer to latitudes, and the pages refer to the epochs (209 monthly solutions). Time is a 209-by-1 vector containing the number of days since January 1, 2002. A MATLAB code ‘read_hhu_ipm_tws.m’ is available for extracting the results and plotting the first month. Alternatively, the variables can be displayed in Panoply Data Viewer, available at https://www.giss.nasa.gov/tools/panoply/ or a Linux-based command ncview.

本数据集包含基于河海大学（Hohai University, HHU）改进质点法（improved point mass, IPM）解算得到的GRACE（Gravity Recovery and Climate Experiment）月尺度陆地水储量异常（terrestrial water storage anomaly, TWSA）网格数据。HHU-IPM-GRACE的月尺度TWSA值以等效水高毫米为单位，基准时段为2002年4月至2022年5月，存储格式为NetCDF（Network Common Data Form）文件。该数据的异常值参考时段为2004年1月至2009年12月。
数据集的空间分辨率为0.25°×0.25°弧度。（注：该分辨率仍属于GRACE的原生分辨率，空间尺度约为300-400千米。）
文件`HHU_IPM_GRACE_TWS_200204_202205_v04.nc`内包含以下变量：`lat`（纬度，latitude）、`lon`（经度，longitude）、`tws`（陆地水储量，terrestrial water storage）以及`time`。其中纬度和经度分别为720×1和1440×1的十进制度弧度向量，分别对应北半球向北、东半球向东的格网中心坐标。陆地水储量数据为1440×720×209的三维矩阵，其中第一维度对应经度、第二维度对应纬度，第三维度对应209个月度解算时段。时间变量为209×1的向量，记录自2002年1月1日起的累计天数。
用户可通过MATLAB代码`read_hhu_ipm_tws.m`提取数据并绘制首个月份的结果；也可通过Panoply数据查看器（可从https://www.giss.nasa.gov/tools/panoply/ 下载）或Linux环境下的命令行工具ncview查看变量内容。

搜集汇总

背景与挑战

背景概述

该数据集包含基于改进点质量（IPM）解决方案的GRACE每月陆地水储量异常（TWSA）网格数据，时间跨度为2002年4月至2022年5月，空间分辨率为0.25度，数据格式为NetCDF文件，并附有MATLAB代码用于数据处理和可视化。