Biography
Biography: Liming Zhou
Abstract
Previous research found that the warming rateobserved for the period 1979–2012 increases dramaticallywith decreasing vegetation greenness over land in mid- and low- latitudes, with the strongest warming rate seen overthe driest ecoregions such as the Sahara desert and the ArabianPeninsula, suggesting warming amplification over deserts.Here I analyze the observed and projected surface temperature anomalies over land between50°S-50°N for the period 1950–2099 by large-scale ecoregion and find strongest warming consistentlyand persistently seen over the driest ecoregions duringvarious 30-year periods, pointing to desert amplification in a warming climate (similar to polar amplification). This amplificationenhances linearly with the global mean greenhouse gases (GHGs) radiative forcing. Possible mechanisms for this amplification are explored by analyzing changes in various variablesrelated to atmospheric profiles, surface radiative forcing, landsurface properties, and surface energy and radiation budget. My results show that desert amplification islikely attributable mostly to a stronger GHGs-enhanced downward longwave radiation forcing reaching the surfaceover drier ecoregions as a consequence of a warmer and thus moister atmosphere in response toincreasing GHGs. These results indicate that desert amplification may represent a fundamental patternof global warming associated with water vapor feedbacks over land in low- and mid- latitudes wheresurface warming rates depend inversely on ecosystem dryness. It is possible that desert amplificationmight involve two types of water vapor feedbacks that maximize respectively in the tropical uppertroposphere and near the surface over deserts, with both being very dry and thus extremely sensitive tochanges of water vapor.