It is found that the latitude of the continent is critical to the establishment of a distinct seasonality of precipitation and a summer monsoon circulation. Low-latitude positions of the continent lead to landlocked precipitation maxima, and poleward positions lead to a mediterra- nean (winter monsoon) climate. In every case, the subsiding branch of the Hadley cell at continental longitudes locks over some part of the land. Variations in the meridional extent of land affect the strength of the Hadley cell and the degree of seasonality in the climate over land. The extension of a subtropical continent into the tropics is critical for establishing heavy convective rainfall over land in the summer. Increasing the zonal extent of land has little effect on the circulation except to increase its zonal extent. When tropical peninsulas are added to a subtropical continent, the distribution of moisture and rain over semi-arid and arid regions of the continent are affected.
last update: 20 October 1994
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