Daymet: Daily Surface Weather Data on a 1-km Grid for North America, Version 2

This data set provides Daymet output data as mosaicked gridded estimates of daily weather parameters for North America, including daily continuous surfaces of day length, precipitation amount, shortwave radiation, snow water equivalent, maximum air temperature, minimum air temperature, and water vapor pressure. The Daymet data product was derived from selected meteorological station data by interpolation and extrapolation algorithms. The current data product covers the period January 1, 1980 to December 31, 2012. Data are available on a daily time step at a 1-km x 1-km spatial resolution in Lambert Conformal Conic projection with a spatial extent that covers the conterminous United States, Mexico, and Southern Canada as meteorological station density allows. Daymet mosaic data sets are available from the ORNL DAAC via two download mechanisms: 1) Data files may be obtained through DAAC search and order tools or directly from the FTP site. 2) Data can be subset spatially and temporally prior to downloading via the THREDDS (Thematic Real-time Environmental Data Services) Data Server. Data are provided in Climate and Forecast (CF) metadata convention compliant (version 1.4) netCDF file formats. Other tools are provided on the ORNL DAAC Daymet website that allow extraction of Daymet variable daily data as a text file for a single pixel or the download of gridded Daymet data in 2 degree by 2 degree tile data sets.本数据集提供适用于北美洲的拼接网格化逐日气象参数估算数据（即Daymet输出数据），涵盖日长、降水量、短波辐射、雪水当量、最高气温、最低气温以及水汽压的逐日连续格网数据。 该Daymet数据集通过插值与外推算法，基于精选气象站点观测数据生成。 本数据集当前的时间覆盖范围为1980年1月1日至2012年12月31日，数据以逐日时间步长提供，空间分辨率为1千米×1千米，采用兰伯特共形圆锥投影（Lambert Conformal Conic）；其空间覆盖范围依据气象站点密度情况，涵盖美国本土、墨西哥以及加拿大南部地区。 Daymet拼接数据集可通过橡树岭国家实验室分布式主动存档中心（ORNL DAAC）获取，支持两种下载方式：1）通过ORNL DAAC的搜索与订购工具，或直接从FTP站点获取数据文件；2）通过THREDDS（专题实时环境数据服务，Thematic Real-time Environmental Data Services）数据服务器，在下载前可对数据进行空间与时间子集截取。数据采用符合气候与预报（CF，Climate and Forecast）元数据规范1.4版本的netCDF文件格式存储。 ORNL DAAC的Daymet官网还提供了其他辅助工具，支持将单个像素的Daymet变量逐日数据导出为文本文件，或以2°×2°瓦片数据集的形式下载网格化Daymet数据。