Gridded Meteorological Data

University of Washington

Department of Civil and Environmental Engineering

Surface Water Modeling Group
 

Data Set: Daily 1/8-degree gridded meteorological data [1 Jan 1949 - 31 Jul 2000]

Citation: If you acquire data from this web site, we request that you please acknowledge this by including text such as: Daily gridded meteorological data obtained from the Surface Water Modeling group at the University of Washington from their web site at http://www.hydro.washington.edu/Lettenmaier/Data/gridded/, the development of which is described by Maurer et al. (2002):

Ref: Maurer, E.P., A.W. Wood, J.C. Adam, D.P. Lettenmaier, and B. Nijssen, 2002, A Long-Term Hydrologically-Based Data Set of Land Surface Fluxes and States for the Conterminous United States, J. Climate 15, 3237-3251.

Data Description: The links below are to files containing daily precipitation (mm/day), maximum and minimum temperature (C), and wind speed (m/s) for each 1/8-degree grid cell, grouped (using the UNIX tar command) by hydrologic area. The individual data files, (which can be extracted using tar xvf <tar filename>) indicate the location center of the grid cell in the file name: data_<latitude>_<longitude>. Each daily data file contains records of daily total precipitation, maximum temperature, minimum temperature, and average 2-meter wind speed in 2-byte integer format (unsigned, signed, signed, signed, respectively). The daily data are stored with multipliers of 40, 100, 100, 100, respectively, so the archived values need to be divided by these multipliers to obtain the variables (see example program segment). These daily data are in little-endian (PC architecture) format. If you need sub-daily interpolation of temperature, or radiative and humidity forcings as well as those listed above, the current VIC code can be run with the OUTPUT_FORCE flag in user_def.h set to TRUE for the cells of interest, and recompiling the program. (see additional sample instructions for using VIC to generate full forcings). If disaggregation of daily precipitation (other than dividing daily precipitation evenly between the timesteps) is desired, one approach is described here. This is designed to preserve the statistical characteristics of time-of-occurence and duration of daily rainfall based on hourly statistics (in the continental U.S. only).

In addition, for some of the hydrologic areas, a monthly time series of the data (for each grid cell) of the same variables (precipitation is a monthly total in mm, other variables are monthly averages), in ascii format, as indicated below. Monthly data are in original units, without multipliers.

Known Problems: 23 Feb 2004: is was discovered that the daily and monthly temperatures for the Colorado basin were corrupt from 1998-2000. These have been corrected and replaced.