[A-AS01] Extreme weathers and disasters in urban environments in East Asia, related to climate change

[AAS01-03] Asymmetric response of sub-diurnal surface air temperature to the global warming effect in the Tokyo region

*Quang Van Doan¹, Fei Chen², Yuki Asano¹, Ying Gu³, Akifumi Nishi⁴, Hiroyuki Kusaka¹, Dev Niyogi⁵ (1.University of Tsukuba, 2.National Center for Atmospheric Research, 3.Shanghai University of Engineering Science, 4.National Defense Academy of Japan, 5.University of Texas at Austin)

Keywords:diurnal temperature range, asymmetric warming, cloudiness feedback

Diurnal temperature range (DTR), defined as the difference between the daily maximum and minimum surface air temperature is a critical climate-change indicator. Here, we, by using pseudo-global warming dynamical downscaling approach with fine-scale Weather Research and Forecast (WRF) model, predict the future change DTR up to 2100 over the Tokyo region, Japan. The prediction shows that the sub-daily temperature in the region will increase asymmetrically, i.e., the greater warming is seen in daily minimum, and the reverse in the daily maximum temperature, resulting in the DTR of 0.5 deg K assuming 2 deg K warming forcing. Moreover, we found that the deficit of shortwave radiative heating during the daytime, which is attributed to the increase in cloud fraction, is a primary reason for the “underwarming” of the daily maximum temperature, thus reducing DTR.