AGU journal highlights - 28 January 2004

The connection between drought and global warming Researchers have identified a mechanism that may play a major role in determining whether rainfall increases or decreases in a region because of global warming. Neelin et al. analyzed tropical rainfall changes associated with El Nino variability and suggest that tropospheric warming linked with El Nino or global warming increases the amount of surface moisture contributing to cloud formation. Precipitation then rises as the moisture increases in the center of convective regions where small-scale atmospheric motion lead to cloud formation. The sum of the atmospheric processes leads to reductions in rainfall at the borders of convection zones that are near dryer regions. The authors used a climate model to simulate global warming and note that the mechanism is the leading cause of tropical drought and closely parallels a similar effect that causes El Nino drought areas. Authors: J. D. (David) Neelin, H. Su, Institute of Geophysics and Planetary Science, University of California at Los Angeles, California; C. Chou, Institute of Earth Sciences, Academia Sinica, Teipei, Taiwan, Republic of China. Source: Geophysical Research Letters (GL) paper: 10.1029/2003GL018625, 2003 Original link: Eurekalert, AGU page Associated Paper link: J. D. Neelin, Chia Chou, and Hui Su, 2003: Tropical drought regions in global warming and El Niño teleconnections. Geophys. Res. Lett.,, 30(24) 2275, doi:10.1029/2003GLO018625. Paper (PDF 2.6 MB). © Copyright 2003 by the American Geophysical Union.