Speaker: Dr. Aiguo Dai (U Albany)
Topic: "Increasing Drought Under Global Warming"
Room: 529 Walker Building (refreshments served)
Time: Monday October 03, 2016 10:30am to 11:30am
Abstract: As air temperature rises, atmospheric demand for moisture increases sharply. Coupled with decreases in light-to-moderate precipitation events, climate models project large increases in drought frequency and intense in the coming decades. This makes one wonder if the recent severe drought events in the U.S. are a precursor to what we might experience in the coming decades. In this talk, I will first discuss some of the basics about drought and its linkage to rising temperatures, and then present an updated analysis about historical drought changes since about 1950, including uncertainty issues related to insufficient observations. I will conclude with model-projected drought changes by the late 21st century. Updated precipitation and streamflow data and the self-calibrated Palmer Drought Severity Index (PDSI) all show consistent drying during 1950–2012 over most Africa, East and South Asia, southern Europe, eastern Australia, and many parts of the Americas. While these regional drying trends resulted primarily from precipitation changes related to multi-decadal oscillations in Pacific sea surface temperatures, rapid surface warming and associated increases in surface vapor pressure deficit since the 1980s have become an increasingly important cause of widespread drying over land. Climate models project that this warming-induced drying trend could continue into the later part of the 21st century over the U.S. and many other land areas.