Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

An Analysis of the Conditional Instability of the Tropical Atmosphere

An Analysis of the Conditional Instability of the Tropical Atmosphere The ice phase is included in thermodynamic calculations of convective available potential energy (CAPE) for a large number of soundings in the tropical atmosphere, at both land and ocean stations. It is found that the positive-buoyancy contribution to CAPE resulting from the latent heat of fusion more than offsets the negative-buoyancy contribution due to water loading in the reversible thermodynamic process. The departure from moist neutrality in much of the tropical atmosphere exhibits a threshold in boundary-layer wet-bulb potential temperature of 22°–23°C. The corresponding sea surface temperature is approximately 26°C, close to the empirical threshold for hurricane formation, which suggests that conditional instability plays an important role in the latter phenomenon. The simultaneous presence of finite CAPE and infrequent deep convection in the tropics is tentatively attributed to the convective inhibition energy (CINE) and to the mixing process that destroys positive buoyancy in incipient cloud parcels. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Monthly Weather Review American Meteorological Society

An Analysis of the Conditional Instability of the Tropical Atmosphere

Williams, Earle; Renno, Nilton
Monthly Weather Review , Volume 121 (1) – Oct 2, 1991
Download PDF
16 pages

Loading next page...
 
/lp/american-meteorological-society/an-analysis-of-the-conditional-instability-of-the-tropical-atmosphere-fX0y0IgdGq
Publisher
American Meteorological Society
Copyright
Copyright © 1991 American Meteorological Society
ISSN
0027-0644
eISSN
1520-0493
DOI
10.1175/1520-0493(1993)121<0021:AAOTCI>2.0.CO;2
Publisher site
See Article on Publisher Site

Abstract

The ice phase is included in thermodynamic calculations of convective available potential energy (CAPE) for a large number of soundings in the tropical atmosphere, at both land and ocean stations. It is found that the positive-buoyancy contribution to CAPE resulting from the latent heat of fusion more than offsets the negative-buoyancy contribution due to water loading in the reversible thermodynamic process. The departure from moist neutrality in much of the tropical atmosphere exhibits a threshold in boundary-layer wet-bulb potential temperature of 22°–23°C. The corresponding sea surface temperature is approximately 26°C, close to the empirical threshold for hurricane formation, which suggests that conditional instability plays an important role in the latter phenomenon. The simultaneous presence of finite CAPE and infrequent deep convection in the tropics is tentatively attributed to the convective inhibition energy (CINE) and to the mixing process that destroys positive buoyancy in incipient cloud parcels.

Journal

Monthly Weather Review – American Meteorological Society

Published: Oct 2, 1991

There are no references for this article.