Evolution of Tropical and Extratropical Precipitation Anomalies During the 1997 to 1999 Enso Cycle

摘要: The 1997–1999 El Nino–Southern Oscillation (ENSO) period was very powerful, but also well observed. Multiple satellite rainfall estimates combined with gauge observations allow for a quantitative analysis of precipitation anomalies in the tropics and elsewhere accompanying ENSO cycle. An examination evolution Nino revealed that dry Maritime Continent (MC) preceded formation positive sea-surface temperature (SST) eastern Pacific Ocean. Thirty- to sixty-day oscillations winter 1996–1997 may have contributed this lag relationship. Furthermore, westerly wind burst events maintained drought over MC. warming equatorial then followed by an increase convection. A rapid transition from La Nina occurred May 1998, as early October–November 1997, indices captured substantial changes anomalies. global patterns event were good agreement strong consistent ENSO-related signals identified earlier studies. Differences included shift Africa during 1997–1998 unusually wet conditions northeast Australia later stages Nino. Also, typically region north tropical mostly 1998–1999 Nina. Reanalysis compared time differences noted. In particular, model had bias towards magnitudes small observations. field, including drying MC eastward progression Pacific, less pronounced Copyright © 2001 Royal Meteorological Society