Northern Hemisphere Circulation and the Principal Components of Subsequent Summer Patterns in North America and West Africa.
Abstract
The winter and spring patterns of the Northern Hemisphere circulation are related to the principal components of the following summer temperature of North America and the summer precipitation of sub-Saharan West Africa. The first two components of the North American temperature and the first component of the West African precipitation are used to describe the dominant modes of the summer atmosphere. The results of correlation analysis indicate that the planetary scale circulation over the North Pacific during winter and spring is significantly related to the following summer circulation of North America. In particular the sea surface temperature in the central North Pacific is found to be a useful predictor of the following North American summer temperature. Examination of the West African precipitation shows that the summer rainfall fluctuation is closely related to the atmospheric moisture contents in the tropics during the preceding winter and spring. A possible impact of the El Nino-Southern Oscillation (ENSO) on the summer circulation is discussed. A teleconnection between the upper tropospheric geopotential field over North America and the precipitation in West Africa may suggest that quasi-stationary waves are important to determine the regional summer circulation patterns in the tropics and the middle latitudes.
- Publication:
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Ph.D. Thesis
- Pub Date:
- September 1987
- Bibcode:
- 1987PhDT........75P
- Keywords:
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- Physics: Atmospheric Science