摘要
This observational study demonstrates that the Somali jet（SMJ） experienced a notable interdecadal transition in not only its lower-level parts（〈 850 hP a） but also its higher-level parts（850-600 h Pa） in the late 1990 s. The results also show that the jet at higher level is more significantly related to East Asian monsoon rainfall than that at lower level. Thus, a new whole-layer SMJ（WSMJ） index which includes variations of the higher-level jet is defined based on the average meridional wind speed at five levels（1000-600 h Pa）. The interdecadal transition of the SMJ can be mainly attributed to the meridional thermal contrast anomalies near the equator which are associated with the three-pole pattern of the southern Indian Ocean.
This observational study demonstrates that the Somali jet（SMJ） experienced a notable interdecadal transition in not only its lower-level parts（〈 850 hP a） but also its higher-level parts（850-600 h Pa） in the late 1990 s. The results also show that the jet at higher level is more significantly related to East Asian monsoon rainfall than that at lower level. Thus, a new whole-layer SMJ（WSMJ） index which includes variations of the higher-level jet is defined based on the average meridional wind speed at five levels（1000-600 h Pa）. The interdecadal transition of the SMJ can be mainly attributed to the meridional thermal contrast anomalies near the equator which are associated with the three-pole pattern of the southern Indian Ocean.
基金
Supported by the National Natural Science Foundation of China(41175051 and 41375069)
National Basic Research and Development(973)Program of China(2012CB957804)
Postgraduate Science and Technology Innovation Project of Jiangsu Province(CXZZ13-0517)
the China Scholarship Council(CSC)
