Seminário: Sea Surface Temperature Structure and Tropical Oceanic Rainfall

19/09/2014 - 14:00
Auditório 1 do IAG (Rua do Matão, 1226, Cidade Universitária)

O seminário do Departamento de Ciências Atmosféricas, intitulado "Sea Surface Temperature Structure and Tropical Oceanic Rainfall", será apresentado por Richard “Rit” Carbone (National Center for Atmospheric Research - Boulder, Colorado, USA) e Yanping Li (University of Saskatchewan - Saskatoon, Saskatchewan, Canada).
For the past 25 years, literature on sea surface temperature structure and its relationship to occurrence of tropical oceanic rainfall has been mixed.  Attribution has been given either to sea surface temperature (SST) itself, or somehow related to gradients of SST.   Unlike previous studies, Li and Carbone (2012) examined this issue from a mesoscale perspective in an attempt to clarify circumstances under which rainfall events are triggered.  From observations in the western Pacific, they showed statistical evidence in support of SST gradients as an important factor.  The maximum normalized frequency of rainfall onset events was near the regional mode of SST, suggesting less sensitivity to SST than commonly inferred from climatology at regional scales.
This talk presents new results applicable to the Eastern Hemisphere in the MJO passband, inclusive of the Indian Ocean, Maritime Continent, and the western Pacific.  A nuanced interpretation emerges concerning probable cause and correlation of rainfall with SST structure.  The interpretation is fully consistent with existing theory and has potential implications for systematic errors in highly parameterized global models.  While the Western hemisphere oceans have yet to be studied in this manner, future findings could have major implications for the Americas, especially in the tropics.