Maximum and minimum temperature trends for the globe: an update through 2004

The IPCC Third Assessment Report noted that minimum temperature generally increased at a much faster rate than maximum temperature from 1950-93, resulting in a widespread decrease in the diurnal temperature range (DTR). These observed changes, particularly in the DTR, have been attributed to variations in cloud cover, precipitation, soil moisture, and atmospheric circulation. In this study we update the IPCC assessment of trends in maximum/minimum temperature and the DTR using a variety of recently acquired datasets that substantially increase spatial and temporal completeness. In general, trends from 1950-2004 are somewhat smaller but otherwise consistent with previous findings (i.e., minimum temperature increased more rapidly than maximum temperature, leading to a continued decline in DTR). In contrast, from 1979-2004 maximum and minimum temperature have roughly comparable trends, muting changes in the DTR.