P2.145 Tropical thick anvil

Thursday, 13 May 2010
Arizona Ballroom 7 (JW MArriott Starr Pass Resort)
Wei Li, Penn State University, University Park, PA; and C. Schumacher

A suite of spaceborne and ground radars was used to investigate variations in the geographical distribution and radiative heating profile of tropical anvil (i.e., thick, non-precipitating cloud associated with deep convection). Tropical anvil occurs most often in regions of large rain accumulation over both land and ocean, but covers disproportionately larger areas over West and Central Africa and other land regions. It appears that more anvil is created per unit convection over land than over ocean. Anvil is also higher and thicker over land than over ocean, which is consistent with observations that show anvil-producing convection over land tends to have higher echo tops and stronger near-surface reflectivities than anvil-producing convection over ocean. Some tropical land regions, especially those affected by monsoon circulations, experience significant seasonal variability in anvil properties and strong interannual anvil variability occurs over the central Pacific due to the El NiƱo-Southern Oscillation. Therefore, the characteristics and occurrence of the parent convection are important factors in describing the climatology of thick anvil across the tropics. Large-scale environmental factors, such as strong upper-level wind shear, also appear to assist the generation of anvil and can in part explain the different anvil statistics over land and ocean. Anvil can locally heat the mid-to-upper troposphere and cool the upper troposphere by many degrees K per day, playing an integral role in the energy budget of tropical convective systems. However, tropics-wide coverage of thick anvil is on the order of 1%, so anvil does not appear to play a significant role in the large-scale tropical circulation.
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