Data Sets/Regional Climatologies

Data Sets/Regional Climatologies

The Climatic Research Unit is engaged in work which is aimed at generating gridded climatologies representing the period 1961-90 for a variety of world regions, and ultimately for the world as a whole. This work has been co-ordinated by Mike Hulme, with working contributions from many other members of the Unit. This page summarises the regional climatologies which have been completed; for a description of the work towards a full global climatology go to Mark New's carbon project page. For information about accessing the completed regional data sets visit the Climate Impacts LINK page Funding support has come from a variety of sources and these are specified as appropriate. More information on the existing regional climatologies can be found for the regions listed below. Stay with this page for more general information about the data sets.

Europe
Great Britain
The British Isles
USA
South Asia
Southern Africa

General Approach:

The interpolation procedure used in this work is based on the thin-plate splines approach develop by Mike Hutchinson from the Australian National University. He kindly supplied the software which has formed the basis of that used here. The most complete description of our approach is contained in Hulme et al. (1995). For producing a land/sea mask for each region we have generally used the following procedure:

Working from an original 5' (for Europe 10') elevation dataset, we have produced mean, max. and min. elevations for each 0.5 cell. The mean is therefore the average of 36 values, while the max. and min. are, respectively, the highest and lowest of these 36 values. The cell is classified as 'land' if the max. elevation is positive and 'ocean' if it is zero or negative. In effect we are saying that a 0.5 cell is 'land' if one 5' cell within it has a positive elevation. This procedure makes for difficulties where land lies below sea-level. For Europe we therefore used the land/sea mask produced by the Environmental Change Unit at Oxford and for North America we forced Death Valley to be 'land'. For other regions we haven't yet checked whether this procedure causes difficulties.

In the documentation below, the following acronyms and conventions apply:

CLD mean monthly cloud cover (100ths). The SUN and CLD variables are interchanged using the procedure described in Hulme et al. (1995).
DIUdiurnal temperature range (C)
FRS (or FD) mean monthly frequency of (ground) frost days
PET calculated using Penman (mm/day) from VAP,RDG,WND and TMP
PRE mean monthly precipitation total (mms)
RD0 (or RD) mean monthly frequency of raindays above 0.1mm
RDG mean daily global radiation (Wm-2) derived from SUN using the method described in Rietveld (1978). This is equivalent to incident solar radiation.
REH derived from the TMP and VAP fields (%)
RIN rainfall intensity per rain day (mm/day) derived from PRE and RD0
SNL days with snow laying
SUN mean monthly sunshine hours total
TMN mean monthly minimum surface air temperature (C)
TMP mean monthly surface air temperature (C). This variable is always the average of the gridded TMX and TMN for reasons explained in Hulme et al. (1995)
TMX mean monthly maximum surface air temperature (C)
VAP mean monthly vapour pressure (approx. 24-hour mean; hPa)
WND mean monthly wind speed (approx. 10m height; ms-1)

(all variables are held as integer values to one decimal place; e.g. 86 = 8.6. There are no missing values)
HI field contains climatology assuming 'max.' cell elevation
LO field contains climatology assuming 'min.' cell elevation
MN field contains climatology assuming mean cell elevation
ZIP file has been zipped using 'zip' under UNIX. Held as binary.

References:

Hulme,M., Conway,D., Jones,P.D., Jiang,T., Barrow,E.M. and Turney,C. (1995)
Construction of a 1961-90 European climatology for climate change impacts and modelling applications Int. J. Climatol., 15, 1333-1363.
Rietveld,M.R. (1978)
A new method for estimating the regression coefficients in the formula relating solar radiation to sunshine Agric. Meteorol., 19, 243-252


These datasets are made available under the Open Database License.
Any rights in individual contents of the datasets are licensed under the
Database Contents License under the conditions of Attribution and Share-Alike.
Please use the attribution Climatic Research Unit, University of East Anglia