HR: 15:10h
AN: A33B-07 INVITED     [Abstracts]
TI: Tropical Teleconnection Sensitivities to Characteristics of El Ni¤o
AU: * KANIKICHARLA, K
EM: kkrishna@colorado.edu
AF: Cooperative Institute for Research in Environmental Sciences, University of Colorado, 216 UCB, Boulder, co 80309 United States
AU: * KANIKICHARLA, K
EM: kkrishna@colorado.edu
AF: Indian Institute of Tropical Meteorology, Dr. Homi Bhabha Road, Pune, 411 008 India
AU: Rajagopalan, B
EM: balajir@colorado.edu
AF: Cooperative Institute for Research in Environmental Sciences, University of Colorado, 216 UCB, Boulder, co 80309 United States
AU: Rajagopalan, B
EM: balajir@colorado.edu
AF: Department of Civil, Environmental and Architectural Engineering, University of Colorado at Boulder,, ECOT 441, UCB 429, boulder, co 80309 United States
AU: Hoerling, M P
EM: martin.hoerling@noaa.gov
AF: NOAA/Climate Diagnostics Center, 325 Broadway, R/CDC1, boulder, co 80305-3328 United States
AB: Examination of all major El Niqo events of the past century and the associated monsoon rainfall anomalies over India suggests different impacts. This empirical evidence challenges the conventional wisdom that El Niqo events in the tropical Pacific Ocean lead to a monolithic deficit in Indian summer monsoon rainfall. For example, during 1997, the strongest El Niqo event on record, Indian monsoon rainfall was inexplicably high. Yet in 2002, a relatively weaker El Niqo event, India experienced one of the worst droughts in recent history. To understand this variability, we explore tropical-wide teleconnection sensitivities to the strength and location of warm sea surface temperature (SST) anomalies in tropical Pacific. Can it be shown, that SST anomalies shifted towards the tropical far Eastern Pacific, (a flavor seen in 1997) alters the subsidence limb of the Walker circulation in a manner to circumscribe its reach over the Indian subcontinent? Likewise, can it be shown that SST anomalies near the dateline are more effective in suppressing Indian monsoon rainfall, as seen in 2002? We test these hypotheses using atmospheric general circulation model (AGCM) experiments forced with idealized tropical Pacific warmings. Implications for tropical monsoon prediction are drawn, including requirements for coupled model forecasts of the SST variations.
DE: 3339 Ocean/atmosphere interactions (0312, 4504)
DE: 4215 Climate and interannual variability (3309)
DE: 4522 El Ni¤o
DE: 1854 Precipitation (3354)
DE: 1620 Climate dynamics (3309)
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting