Stronger Global Warming on Nonrainy Days in Observations From China

摘要

Nonrainy days have rather different hydrologic and radiative conditions than rainy days, but few investigations considered how these different conditions contribute to the observed global warming. Here, we show that global warming is considerably stronger on nonrainy days using observations from China. We find that trends in mean temperature on nonrainy days are about 0.1 ° C/10 yr higher than on rainy days, and that about 80% of the total temperature increase is contributed by nonrainy days. The main reason is likely to be a stronger sensitivity of downwelling longwave radiation to greenhouse forcing on nonrainy days due to fewer clouds and water vapor compared with rainy days, which is not a hydrological effect but mainly a radiative effect. Our findings are consistent with the stronger mean temperature trends in drier regions and imply that the different temperature sensitivities on nonrainy and rainy days may have profound effects on natural and social systems.