M. New et al., Representing twentieth-century space-time climate variability. Part II: Development of 1901-96 monthly grids of terrestrial surface climate, J CLIMATE, 13(13), 2000, pp. 2217-2238
The authors describe the construction of a 0.5 degrees lat-long gridded dat
aset of monthly terrestrial surface climate For the period of 1901-96. The
dataset comprises a suite of seven climate elements: precipitation, mean te
mperature, diurnal temperature range, wet-day frequency, vapor pressure, cl
oud cover, and ground frost frequency. The spatial coverage extends over al
l land areas, including oceanic islands but excluding Antarctica. Fields of
monthly climate anomalies, relative to the 1961-90 mean, were interpolated
from surface climate data. The anomaly grids were then combined with a 196
1-90 mean monthly climatology (described in Part I) to arrive at grids of m
onthly climate over the 96-yr period.
The primary variables-precipitation, mean temperature, and diurnal temperat
ure range-were interpolated directly from station observations. The resulti
ng time series are compared with other coarser-resolution datasets of simil
ar temporal extent. The remaining climatic elements, termed secondary varia
bles, were interpolated from merged datasets comprising station observation
s and, in regions where there were no station data, synthetic data estimate
d using predictive relationships with the primary variables. These predicti
ve relationships are described and evaluated.
It is argued that this new dataset represents an advance over other product
s because (i) it has higher spatial resolution than other datasets of simil
ar temporal extent, (ii) it has longer temporal coverage than other product
s of similar spatial resolution, (iii) it encompasses a more extensive suit
e of surface climate variables than available elsewhere, and (iv) the const
ruction method ensures that strict temporal fidelity is maintained. The dat
aset should be of particular relevance to a number of applications in appli
ed climatology, including large-scale biogeochemical and hydrological model
ing, climate change scenario construction, evaluation of regional climate m
odels, and comparison with satellite products. The dataset is available fro
m the Climatic Research Unit and is currently being updated to 1998.