A mechanism for the influence of vegetation on the response of the diurnal temperature range to changing climate

We propose a new mechanism that could contribute to The highly interactive nature of general circulation models the observed decrease in the diurnal temperature range (DTR) (GCMs) as well as weaknesses in their parameterizations make it over the last century: the physiological behavior of vegetation in difficult to identify the mechanisms underlying predicted changes response to climate. Using a physiologically based land surface in the DTR. The purpose of this study is to examine how the model, we analyze the influence of vegetation on the response of diurnal temperature cycle of vegetated land surfaces responds to the D TR to perturbations in the state of the climate and changes in external forcing and the biophysical state of the vegetation. Increasing down-welling long wave radiation and vegetation. We use the SiB2 land surface model [Sellers et al., surface air temperature together, conditions that could occur as a 1996a] in an off-line mode with prescribed meteorology for a result of doubling of atmospheric CO2, produced little change in number of scenarios highlighting the impact of vegetation on the DTR. Changes in the state of the vegetation (i.e. amount, DTR. Off-line simulations do not account for feedback between physiological capacity, stress) produce changes in the DTR of the order or larger than observed. Results emphasize that DTR modeling studies need to consider vegetation responses and suggest that recently reported increases in vegetation over the last decade could contribute to the observed decreases in the DTR.