CRU climate data set.

Authors: Daniel Falster & Ian Wright, Oct 2005

The Climate Research Unit at Norwich, UK has produced a global set of high-resolution climate grids, based on weather stations records taken between 1961-1990. These data are available and can be queried using these tools to extract data for a list of site localities, specified by latitude and longitude. Two data sets are available:

The CRU_CL_1.0 data (New et al. 1999) gives mean monthly surface climate over global land areas, excluding Antarctica, interpolated from station data to 0.5 degree lat/lon for a range of variables: precipitation and wet-day frequency, mean temperature and diurnal temperature range, vapour pressure, sunshine, cloud cover, ground-frost frequency and windspeed.  The data are described here and available for download at http://ipcc-ddc.cru.uea.ac.uk/obs/get_30yr_means.html

The CRU_CL_2.0 data (New et al. 2002) is a 10-minute latitude/longitude data set of mean monthly surface climate over global land areas, excluding Antarctica. The climatology includes 8 climatic variables: precipitation, wet-day frequency, temperature, diurnal temperature range, relative humidity,sunshine duration, ground frost frequency and windspeed. The data are described here and are available for download at http://www.cru.uea.ac.uk/cru/data/tmc.htm

After downloading the data, you can use these tools to extract data for a list of sites, specified by grid location. Input is a file with a list locations in tab-delimited form (example), which must be saved in the same directory as your program and the decompressed data-files. Latitude is in the range -90 to 90 deg South to North, and longitude -180 to 180 deg West to East, both measured in degrees decimal. Output from both programs is stored in a text file in the same directory, giving monthly averages for each variable.

The CRU1.0_data extraction tool is used for querying the CRU_CL_1.0 data set.
ABOUT: The data files are 360x720 grid of mean monthly values, with each data point of column width 5 chars and no delimiters. Latitudes and Longitudes are transformed into the appropriate columns / rows of data using the transformation: (int) 1/gridsize*(latitude+ gridsize/2 - minimum grid value).
DOWNLOAD: Windows executable | C++ code (right click and select “save-as”)

The CRU2.0_data extraction tool is used for querying the CRU_CL_2.0 data set.
ABOUT: The data files provide a list of grid locations with interpolated values. The program searches for the reference location closest to the site coordinates.
DOWNLOAD: Windows executable | C++ code (right click and select “save-as”

A fortran program for the CRU1.0 data is also available here. A version suitable for GIS has also been developed here.

Publications
New, M, Hulme, M, and Jones, P. 1999. Representing twentieth-century space-time climate variability. Part I: Development of a 1961-90 mean monthly terrestrial climatology. Journal of Climate 12:829-856 pdf

New, M, Lister, D, Hulme, M, and Makin, I. 2002. A high-resolution data set of surface climate over global land areas. Climate Research 21:1-25 pdf