POSSIBLE INFLUENCES OF THE TROPICAL INDIAN OCEAN DIPOLE ON THE EASTWARD PROPAGATION OF MJO

• 作 者: 袁媛 杨辉 李崇银
• 机 构: National Climate Center,Laboratory for Climate Studies, China Meteorological Administration,LASG, In
• 出 处: Journal of Tropical Meteorology
• 发表日期: 2014年02期
• 关键词: equatorial southeastern Indian tropical convection anomalous zonal winds eastwar

Based on multiple datasets, correlation and composite analyses, and case studies, this paper investigated possible influences of the Indian Ocean dipole(IOD) mode on the eastward propagation of intraseasonal oscillation in the tropical atmosphere. The results showed that(1) the 30-60 day outgoing longwave radiation anomalies in the southeastern Indian Ocean and the 30-60 day 850-hPa zonal wind anomalies over the equatorial central Indian Ocean were significantly correlated with the IOD index;(2) during positive IOD years, the anomalously cold water in the southeastern Indian Ocean and the 850-hPa anomalous easterlies over the equatorial central Indian Ocean might act as barriers to the continuously eastward propagation of the intraseasonal convection, which interrupts the Madden-Julian oscillation(MJO) propagation in the eastern equatorial Indian Ocean and western Pacific; and(3) during negative IOD years, the anomalously warm water in the southeastern Indian Ocean and the low-level westerly anomalies over the equatorial central Indian Ocean favor the eastward movement of MJO.

Based on multiple datasets, correlation and composite analyzes, and case studies, this paper attempcts influences of the Indian Ocean dipole (IOD) mode on the eastward propagation of intraseasonal oscillation in the tropical atmosphere. The results showed that (1) the 30- 60 days outgoing longwave radiation anomalies in the southeastern Indian Ocean and the 30-60 day 850-hPa zonal wind anomalies over the equatorial central Indian Ocean were significantly correlated with the IOD index; (2) during positive IOD years, the anomalously cold water in the southeastern Indian Ocean and the 850-hPa anomalous easterlies over the equatorial central Indian Ocean might act as barriers to the continuous eastward propagation of the intraseasonal convection, which interrupts the Madden-Julian oscillation (MJO) propagation in the eastern equatorial Indian Ocean and western Pacific; and (3) during negative IOD years, the anomalously warm water in the southeastern Indian Ocean and the low-level we sterly anomalies over the equatorial central Indian Ocean favor the eastward movement of MJO.