Effects of the Northeast Monsoon on the Equatorial Westerlies Over Indonesia.

摘要

The possible cross equatorial influences of the Northern Hemisphere on the zonal wind along 10 deg S in the Indonesia-Arafura Sea region are studied by using a 14-year data set. Composites of time series of individual circulation parameters and surface flow charts reveal a correlation between the northeastern monsoon of the Northern Hemisphere and the Southern Hemisphere summer monsoon. The correlation is significantly stronger during the middle season compared to late season. During the late season distinct patterns of changes are found in the Australian monsoon trough and upper tropospheric flow. This reflects a stronger connection between summer monsoon and midlatitude baroclinic systems within the Southern Hemisphere. Thus the mid-season events of the southern monsoon wind strengthening are more influenced by surges in the northeast monsoon in the Northern Hemisphere; while the late-season events may be due to midlatitude baroclinic effects in the Southern Hemisphere rather than the northern cold surges.