DOI: 10.7910/dvn/a31iw6
title: Replication Data for: Vegetation Responses to 2012-2016 Drought in Northern and Southern California

description: Title: Monthly 4-km grids of self-calibrated Palmer Drought Severity Index (PDSIsc) for the Contiguous United States during 1895-2018
The 4-km self-calibrated PDSIsc data (1895-2018) were generated using an updated version of the dataset developed by Williams et al. (2015). For these PDSIsc calculations, potential evapotranspiration was calculated using the physically-based Penman-Monteith equation, which accounts for effects of temperature, humidity, wind speed, and net radiation (Allen, 1998; Monteith, 1965). Williams et al. (2015) calculated PDSIsc from a wide range of climate products. We use the PDSIsc records derived from precipitation and temperature data from Vose et al. (2014) to be consistent with NOAA climate division data, dew point data from PRISM (Daly et al., 2002; PRISM Climate Group, 2004), and wind speed and insolation data from the second phase of the North American Land Data Assimilation System (Mitchell et al., 2004), which are extended for years prior to 1979 using data from the Princeton Global Forcing (PGF) dataset (Sheffield et al. 2006). The PGF only goes back to 1901, so wind and solar data for 1895-1900 were set to the climatological means of 1921-2000.
Each annual file is a .mat file (formatted for Matlab) that contains a data cube called “PDSIsc.” The 3-D data cube has dimensions of (1) latitude, (2) longitude, and (3) month. The PDSIsc values have been multiplied by 100 and rounded to save space.
The lat and lon coordinates are as follows:
Center of minimum latitude grid cell: 24.0625020664597
Center of minimum longitude grid cell: -125.020833333337
Grid cell resolution: 1/24 degrees
Projection = longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0

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