Revised 12/11/01 GLOBAL 30-YEAR MEAN MONTHLY CLIMATOLOGY, 1930-1960, V.2.1 CRAMER AND LEEMANS README file for the new Cramer&Leemans database (NB: this is a technical note only, the complete documentation will be produced later) Potsdam, 12/8-1996 This database is a major update of the Leemans & Cramer database (Leemans & Cramer 1991). It currently contains monthly averages of mean temperature, temperature range, precipitation, rain days, and sunshine hours for the terrestrial surface of the globe, gridded at 0.5 degree longitude/latitude resolution. It was generated from a large data base, using the partial thin-plate splining algorithm developed by Michael F. Hutchinson, Canberra (Huthcinson & Bischof 1983). Before using this data set in a publication, please contact the data originator with a brief explanation of the intended use. Wolfgang Cramer Potsdam Institute of Climate Impact Research Tel.: +49-331-288-2521 Fax: +49-331-288-2600 email: wolfgang.cramer@pik-potsdam.de --------------------------------------------- Data Citation: -------------- The data set should be cited as follows: Cramer, W.P., and R. Leemans. 1999. Global 30-Year Mean Monthly Climatology, 1930-1960, V.2.1 (Cramer and Leemans). Available online [http://www.daac.ornl.gov/] from the ORNL Distributed Active Archivve Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee, U.S.A. The dataset currently consists of fifteen files. The data is available in three different formats (ASCII, binary, GRIDASCII). Pixel resolution is 30' (0.5 degree). ASCII format (5 files): ------------- clou.grd (2f6.1,12f3.0) : lon, lat, average monthly cloudiness (% sunshine hours of potential hours per month) prec.grd (2f6.1,12f5.0) : lon, lat, average monthly precipitation (mm/month, uncorrected for raing-gauge bias) rd.grd (2f6.1,12f3.0) : lon, lat, average monthly number of rain days tmean.grd (14f6.1) : lon, lat, average monthly surface air temperature (degreec C x 10) tran.grd (14f6.1) : lon, lat, average monthly temperature range (degreec C x 10) All grd-files contain the same 62483 pixels in the same order, with 30' latitude and longitude resolution. The coordinates are in degree-decimals and indicate the SW corner of each pixel. Topography is from ETOPO5 and indicates modal elevation. Other resolutions may be added later. Binary format (5 gzipped tar files, 120 files when uncompressed): -------------- cloud_binary.tar.gz - a gzipped tar file containing 12 binary image files (bsq) and 12 header text files (*.hdr) (cloud_1.bsq - cloud_12.bsq) - percentage of monthly sunshine hours. precip_binary.tar.gz - a gzipped tar file containing 12 binary image files (bsq) and 12 header text files (*.hdr) (precip_1.bsq - precip_12.bsq) - monthly mean precip., mm/per month. rd_binary.tar.gz - a gzipped tar file containing 12 binary image files (bsq) and 12 header text files (*.hdr) (rd_1.bsq - rd_12.bsq) - monthly mean number of rain days. tmean_binary.tar.gz - a gzipped tar file containing 12 binary image files (bsq) and 12 header text files (*.hdr) (tmean_1.bsq - tmean_12.bsq) - monthly mean temperature, degrees C x 10. tran_binary.tar.gz - a gzipped tar file containing 12 binary image files (bsq) and 12 header text files (*.hdr) (tran_1.bsq - tran_12.bsq) - monthly temperature range, degrees C x 10. These binary image files can be viewed with any standard image viewing package. The files have an external header file (*hdr) and are in band sequential format (*bsq). Please see header files for image specifications such as bytes-per-pixel. The data files were compressed using the tar and gzip commands under unix. Uncompress them with tar and gunzip under unix, or with winzip or something similar on a non-unix machine. GRIDASCII format (5 gzipped tar files, 60 files when uncompressed): ----------------- cloud_gridascii.tar.gz - a gzipped tar file containing 12 gridascii files (dat) (cloud_1.dat - cloud_12.dat) - percentage of monthly sunshine hours. precip_gridascii.tar.gz - a gzipped tar file containing 12 gridascii files (dat) (precip_1.dat - precip_12.dat) - monthly mean precip, mm/month. rd_gridascii.tar.gz - a gzipped tar file containing 12 gridascii files (dat) (rd_1.dat - rd_12.dat) - monthly mean number of rain days. tmean_gridascii.tar.gz - a gzipped tar file containing 12 gridascii files (dat) (tmean_1.dat - tmean_12.dat) - monthly mean temperature, degrees C X 10. tran_gridascii.tar.gz - a gzipped tar file containing 12 gridascii files (dat) (tran_1.dat - tran_12.dat) - monthly temperature range, degrees C x 10. The data files were compressed using the tar and gzip commands under unix. Uncompress them with tar and gunzip under unix, or with winzip or something similar on a non-unix machine. These data files are in ASCII Grid format for Arc/Info. Each file contains a single ASCII array with integer values in row-major order. The first six lines contain header information. Coordinates listed below are in decimal degrees. The file format is: ncols 720 nrows 360 xllcorner -180 yllcorner -90 cellsize 0.5 NODATA value -9999 row 1 row 2 . . . row n Note: The end of each row of data from the grid is terminated with a carriage return in the file. To import this file into ArcInfo use the following command at an ARC prompt: ASCIIGRID {in_ascii_file} {out_grid} {INT|FLOAT} Arguments: {in_ascii_file} - the ASCII file to be converted. {out_grid} - the name of the grid to be created. {INT|FLOAT} - the data type of the output grid. INT - integer, FLOAT - floating point. ------------------------------------------------------------------------------- This is unpublished material. However, the database for tmean, prec and clou is consistently the same as it is used by a large range of global modelling teams, e.g. in the IGBP NPP model intercomparison. It is internally referred to as version 2.1. Wolfgang Cramer Potsdam Institute of Climate Impact Research Tel.: +49-331-288-2521 Fax : 2600 e-mail: wolfgang.cramer@pik-potsdam.de