Global Warming Holes: Climate-Ecosystem Feedbacks

Zaitao Pan

St. Louis University


A summer daytime “warming hole (WH)” in the central U.S. was identified observationally in the 20th century as well as in a regional model’s future scenario climate in the mid-21st century.  In this talk we report the finding of additional major summer WHs (i.e., cooling centers) in southeastern China and central South America that occurred in the 20th century.  All the three WHs are located downstream of the world’s most predominant low-level jets (LLJ) areas where mesoscale convective systems (MCSs) produce heavy summer rainfall over regions of intensive agriculture. Increased LLJ-related moisture convergence in the WH regions enhanced cloudiness and thus resulted in large attenuation of daytime solar radiation, partly explaining the opposite trends in daily maximum and minimum temperatures in the WHs during summer. The prominent MCS activity in WH regions increased rainfall and moist in soil, thus reducing the daytime sensible heating and resulting in cooling near the surface.