Daily twelve-digit hydrologic unit code aggregations of snow water equivalent, soil moisture, and actual evapotranspiration estimates from the National Hydrologic Model Precipitation Runoff Modeling System forced with CONUS404-BA

This data release contains three variables from the National Hydrologic Model Infrastructure with the Precipitation-Runoff Modeling System (NHM-PRMS) version 1.1 modeling application forced with CONUS404-BA (Markstrom and others, 2024) from January 1st, 1980 through September 25th, 2021 that are summarized to a twelve-digit hydrologic unit code for the spatial extent of the conterminous United States at a daily timestep. The three variables presented here are snow water equivalent, actual evapotranspiration, and soil moisture fraction. There are three netCDF files of daily, modeled data; one for each of the following variables: actual evapotranspiration - "huc12_daily_nhmprms-conus404ba_actet.nc", soil moisture fraction - "huc12_daily_nhmprms-conus404ba_soil_moisture_fraction.nc", and snow water equivalent - "huc12_daily_nhmprms-conus404ba_pkwater_equiv.nc".
Additionally, two supplementary files are also included in this data release. The first file (“weights_hru_to_huc12_nhmprms_conus404ba.csv”) contains the spatial weights or fraction that is used to “weight” the modeling output in the area-weighting process. The second file (“summed_weights_per_huc12_nhmprms_conus404ba.csv”) contains the total fractional area within each twelve-digit hydrologic unit code that is covered by the modeling output and is important for filtering results in the data file (where a fractional coverage may be less than one).

本数据集发布内容包含基于国家水文模型基础设施-降水径流模拟系统（National Hydrologic Model Infrastructure with the Precipitation-Runoff Modeling System, NHM-PRMS）版本1.1的模拟结果，该模拟以CONUS404-BA（Markstrom等，2024）作为强迫驱动场数据，时间跨度为1980年1月1日至2021年9月25日，空间范围覆盖美国本土，所有模拟结果已汇总至十二位水文单元代码（twelve-digit hydrologic unit code, HUC12）尺度，时间步长为日尺度。
本次发布的模拟变量共计三项，分别为雪水当量、实际蒸散发与土壤湿度占比。本数据集包含三个日尺度模拟数据的netCDF格式文件，分别对应上述三个变量：实际蒸散发对应文件为"huc12_daily_nhmprms-conus404ba_actet.nc"，土壤湿度占比对应文件为"huc12_daily_nhmprms-conus404ba_soil_moisture_fraction.nc"，雪水当量对应文件为"huc12_daily_nhmprms-conus404ba_pkwater_equiv.nc"。
此外本数据集还附带两个辅助文件。第一个辅助文件（"weights_hru_to_huc12_nhmprms_conus404ba.csv"）存储了面积加权流程中用于对模拟输出结果进行加权的空间权重或占比系数；第二个辅助文件（"summed_weights_per_huc12_nhmprms_conus404ba.csv"）存储了每个十二位水文单元代码（HUC12）范围内模拟结果覆盖的总分数面积，该信息可用于筛选数据文件中的结果，当模拟覆盖分数小于1时，该文件的作用尤为关键。