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Warming Warms the Warmest Worst

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Tuesday, 06 November 2018, 10:30

 

Tuesday, November 6, 2018. 10:30AM. Warming Warms the Warmest Worst. Suqin Duan, Tsinghua University/UC Berkeley. Sponsored by NOAA GFDL. More information here.

 

We diagnose the changes to the hottest summertime daytime-maximum temperatures and find that, over places with relatively high soil moisture, the extreme summertime temperatures grow with global warming about 20% faster than the mean temperature. We refer to this phenomenon as Warming Warms the Warmest Worst (WWWW). The CMIP5 models predict WWWW over the Southern United States, Western Europe, Central and Southern Africa, India, Southeast Asia, and South America. We present several lines of evidence that WWWW is caused by changes in precipitation and feedbacks involving surface (soil, canopy and ponded water) moisture: precipitation is becoming more episodic in warming climate, i.e. rain events are becoming heavier yet the dry-spells among rain events are getting longer. Longer dry-spells lead to an increased depletion of surface moisture, a shift towards a higher Bowen ratio, and, therefore, an amplification of the hot daytime-maximum temperatures.

 

 

Location  NOAA GFDL, Smagorinsky Seminar Room, Princeton University, Princeton, NJ