Seasonal Transition of SST Anomalies in the Tropical Indian Ocean during El Nino and Indian Ocean Dipole Years

スポンサーリンク

概要

• 論文の詳細を見る

• We investigated seasonal transition of dominant modes of sea surface temperature anomalies (SSTAs) in the tropical Indian Ocean, analyzing the National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis products (NCEP/NCAR reanalyses), the Global sea-Ice and SST dataset (GISST2.3b), and the Simple Ocean Data Assimilation (SODA). During the coincidence years when the Indian Ocean Dipole (IOD) is followed by the major El Nino during boreal autumn-winter season, surface dipole structure in the tropical Indian Ocean tends to turn into the basinwide warm pattern in the November-December period. In contrast, the subsurface dipole keeps its structure from boreal autumn to winter. Such a surface-confined transition of SSTA is induced by latent heat flux anomalies in the eastern Indian Ocean. These latent heat flux anomalies are associated with changes in scalar wind speed anomalies. The zonal direction of climatological surface winds changes from easterly into westerly over the eastern Indian Ocean in November-December, while the anomalous Walker circulation during the El Nino induces easterly surface wind anomalies to persist there. As a result, deceleration of scalar wind speed takes place during boreal winter, and leads to warming of SST through suppressed evaporation. In addition to these latent heat flux anomalies, incoming solar radiation anomalies contribute to the net surface warming during this period. Furthermore, we discuss the role of the ocean dynamics for keeping the warm SSTAs in the western Indian Ocean.

• 社団法人日本気象学会の論文
• 2004-08-25

著者

• Tanimoto Youichi

  Graduate School Of Environmental Earth Science Hokkaido University

• TOKINAGA Hiroki

  Graduate School of Environmental Earth Science, Hokkaido University

• Tokinaga Hiroki

  Graduate School Of Environmental Earth Science Hokkaido University

関連論文

• Seasonal Transition of SST Anomalies in the Tropical Indian Ocean during El Nino and Indian Ocean Dipole Years
• Inter-hemispheric Decadal Variations in SST, Surface Wind, Heat Flux and Cloud Cover over the Atlantic Ocean

スポンサーリンク