NLDAS VIC Land Surface Model L4 Monthly 0.125 x 0.125 degree V002 (NLDAS_VIC0125_M) at GES DISC

This data set contains a series of land surface parameters simulated from the VIC land-surface model (LSM) for Phase 2 of the North American Land Data Assimilation System (NLDAS-2). The data are in 1/8th degree grid spacing and range from January 1979 to present. The temporal resolution is monthly. The file format is WMO GRIB-1. The NLDAS-2 monthly Noah model data were generated from the NLDAS-2 hourly Noah model data, as monthly accumulation for rainfall, snowfall, subsurface runoff, surface runoff, total evapotranspiration, snow melt, and monthly averages for other variables. Each monthly period is from 00Z at start of the month to 23:59Z at end of the month, with the exception of the very first month in the data set (January 1979), which starts at 00Z 02 January 1979. Also, for the first month (January 1979), since the variables listed as instantaneous in the README file do not have valid data exactly on 00Z 02 January 1979, this one hour is not included in the average for this one month.

A brief description about the NLDAS-2 monthly VIC model data can be found from the dataset landing page for NLDAS_VIC0125_H_002 and the NLDAS-2 README document.

Details about the NLDAS-2 configuration of the VIC LSM can be found in Xia et al. (2012). The version of the VIC model for the NLDAS-2 VIC data available from the NASA GES DISC is VIC-4.0.3; this version of the VIC model is the same as used in Sheffield et al. (2003).

The NLDAS-2 VIC monthly data contain forty-three fields. The data set applies a user-defined parameter table to indicate the contents and parameter number. The GRIBTAB file shows a list of parameters for this data set, along with their Product Definition Section (PDS) IDs and units.

For information about the vertical layers of the Soil Moisture Content (PDS 086), Soil Temperature (PDS 085), and Liquid Soil Moisture Content, please see the README Document or the GrADS ctl file.

本数据集收录了北美洲陆地数据同化系统第二阶段（NLDAS-2）中，由VIC陆地表面模型（Land Surface Model，LSM）模拟的一系列地表参数。数据以1/8度网格间距进行划分，时间跨度从1979年1月至今。时间分辨率为月度。数据文件格式为WMO GRIB-1。NLDAS-2月度Noah模型数据由NLDAS-2小时度Noah模型数据生成，涉及降雨、降雪、地下径流、地表径流、总蒸散量、积雪融化以及其他变量的月度累积值。每个月度周期从月初的00Z时开始至月末的23:59Z结束，数据集中的第一个月（1979年1月）的起始时间为1979年1月2日的00Z时。需要注意的是，由于README文件中列为瞬时的变量在1979年1月2日的00Z时没有有效数据，因此这一小时的数据未包含在该月平均值的计算中。有关NLDAS-2月度VIC模型数据的简要描述，可查阅NLDAS_VIC0125_H_002数据集的着陆页面以及NLDAS-2 README文档。VIC LSM在NLDAS-2中的配置细节可参考Xia等人在2012年的研究。从NASA GES DISC获取的NLDAS-2 VIC数据所使用的VIC模型版本为VIC-4.0.3，该版本与Sheffield等人于2003年所使用的版本相同。NLDAS-2 VIC月度数据包含四十三项字段。数据集采用用户定义的参数表来指示内容及其编号。GRIBTAB文件展示了该数据集的参数列表，包括其产品定义部分（PDS）标识符和单位。关于土壤含水量（PDS 086）、土壤温度（PDS 085）和液态土壤含水量垂直层的信息，请参阅README文档或GrADS ctl文件。