The authors document the annual cycle of the diurnal temperature range (DTR) in the contiguous United States based on 40- to 50-year records of daily maximum and minimum temperature at 235 stations. Characteristic regional and seasonal features of the DTR are examined by assessing the relative effects of cloudiness, relative humidity, vegetation, snow cover, and other factors on the DTR, using daily surface observations of a number of other surface variables, twice-daily 850-mb temperatures from the NCEP Reanalysis Project, and weekly values of the Normalized Difference Vegetation Index.
The goal of this research is to supply the background information essential to the successful interpretation of long-term trends in the DTR and provide a base climatology that can be used in the evaluation of conditions in the atmospheric boundary layer simulated by regional climate models