These regional climatologies have been superseded by the CRU CL global climatologies. The regional pages are still provided as a description of these prior regional climatologies, though the regional datasets are no longer available.
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.
EuropeGeneral 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). |
DIU | diurnal 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) |
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:
|