Amir Mohsen
متخصص بخش هواشناسی
[h=2]3.6 Tropical Circulation and Precipitation Distribution The large-scale circulation features in the tropics affects the distribution of precipitation over tropical ocean basins and nearby continental regions. In general, the subtropical eastern ocean and nearby continent are dry. Moving westward, the subtropical ridge and trade wind inversion weaken, clouds grow taller, and precipitation intensity and amount increase as depicted schematically in Fig. 3.62. The major exception to this rule is the Indian Ocean where monsoon westerlies dominate.
Fig. 3.62. Idealized distribution of precipitation influenced by the subtropical highs, ITCZ and trade wind inversion.
The wettest regions are found over the western tropical ocean basin, the result of pooling of warm surface waters driven by the trade winds. The warmest ocean is the tropical western Pacific, a region known as the Tropical Warm Pool. Heavy precipitation over nearby land results from evaporation from the warm ocean and water vapor being advected downstream. Moderately wet regions are found to the north and east of the very wet areas. Figure 3.63 confirms the conceptual pattern of precipitation and prevailing flow for the tropical Atlantic and Pacific during July and as well as the southeast Indian Ocean during January.
Fig. 3.63. Seasonal mean precipitation (shaded, 925 hPa horizontal wind vectors, and 500 hPa geopotential heights (contoured every 10 dam) for (a) Jun-Aug and (b) Dec-Feb. Precipitation data from Xie and Arkin (1997) for the period 1979-1999; wind and geopotential height data from ERA-40 for the period 1962-2001. (from Chang et al. 2005)[SUP]35
اینهم لینک اصلی مطلب که بسیار مفید و آموزنده است:
http://www.goes-r.gov/users/comet/tropical/textbook_2nd_edition/navmenu.php_tab_4_page_6.0.0.htm
[/SUP]
