Research: With colleagues David Lister and Phil Jones from the Climatic Research
Unit at the University of East Anglia in Norwich, and Jean Palutikof at the Met Office
in Exeter,  I have explored the known relationship between incident short wave
radiation, soil moisture, and temperature.  Not surprisingly, when the soil is moist,
the majority of the incident radiation energy heats the soil and can be absorbed
through the latent heat of evaporation rather than through the conductive and
radiative heating of the air heating the air above the soil (sensible heat).

HadCM3: We used the Hadley Centre coupled general circulation model, HadCM3
to examine the correlation between soil moisture and both average and extreme
temperatures.  While the average temperature is seen to rise during the 21st
century, the extreme temperatures rise much further.  The consequences of this
behavior are both an increase in the number of extreme hot days and a dramatic
increase in the lengths of hot spells predicted by HadCM3 as the 21st century
progresses.

Extensions: We are extending this study by examining the relationship between
actual soil moisture measurements and extreme temperatures.  Time series of
soil moisture measurements are now availble at a number of sites both in the
US and in the world.

Publications: B.B. Brabson, D.H. Lister, P.D. Jones, J.P. Palutikof, Soil moisture
and predicted spells of extreme temperatures in Britain, Journal of Geophysical
Research Vol. 110, D05104, doi: 10.1029/2004JD005156, 2005.

Updated: January 2006