M. New et al., Representing twentieth-century space-time climate variability. Part I: Development of a 1961-90 mean monthly terrestrial climatology, J CLIMATE, 12(3), 1999, pp. 829-856
The construction of a 0.5 degrees lat x 0.5 degrees long surface climatolog
y of global land areas, excluding Antarctica, is described. The climatology
represents the period 1961-90 and comprises a suite of nine variables: pre
cipitation, wet-day frequency, mean temperature, diurnal temperature range,
vapor pressure, sunshine, cloud cover, ground frost frequency, and wind sp
eed. The climate surfaces have been constructed from a new dataset of stati
on 1961-90 climatological normals, numbering between 19 800 (precipitation)
and 3615 (wind speed). The station data were interpolated as a function of
latitude, longitude, and elevation using thin-plate splines. The accuracy
of the interpolations are assessed using cross validation and by comparison
with other climatologies.
This new climatology represents an advance over earlier published global te
rrestrial climatologies in that it is strictly constrained to the period 19
61-90, describes an extended suite of surface climate variables, explicitly
incorporates elevation as a predictor variable, and contains an evaluation
of regional errors associated with this and other commonly used climatolog
ies. The climatology is already being used by researchers in the areas of e
cosystem modelling, climate model evaluation, and climate change impact ass
essment.
The data are available from the Climatic Research Unit and images of all th
e monthly fields can be accessed via the World Wide Web.