Effects of Persistent, Midlatitude Mesoscale Regions of Convection on the Large-Scale Environment during the Warm SeasonSource: Journal of the Atmospheric Sciences:;1996:;Volume( 053 ):;issue: 023::page 3503Author:Stensrud, David J.
DOI: 10.1175/1520-0469(1996)053<3503:EOPMMR>2.0.CO;2Publisher: American Meteorological Society
Abstract: Over a 2½-day period beginning 0000 UTC 11 May 1982, 15 mesoscale convective systems (MCSs) developed and moved eastward across the moist axis located over the southern plains of the United States. While the 6?18-h lifetimes of each of these individual MCSs are not sufficiently long to influence the large-scale environment greatly, it is possible that the cumulative effects of the entire group of MCSs can produce significant changes in the large-scale flow patterns. This hypothesis is investigated using output from two runs of a sophisticated mesoscale model. One run includes the effects of convection, and the other does not. Results indicate that in low levels, the inflow of warm, moist air into the convective region is increased when convection is allowed in the model, enhancing the likelihood that convection will continue and thereby acting as a positive feedback mechanism. In upper levels, the convection acts as a Rossby wave source region and produces significant upper-level perturbations that cover at least 50° longitude spread. Convective effects also influence cyclogenesis since the MCSs strengthen the low-level baroclinicity and modify the phase relationship between pressure and thermal waves in the midlevels. Thus, it is clear that the effects of a persistent, mesoscale region of convection on the large-scale environment are substantial.
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contributor author | Stensrud, David J. | |
date accessioned | 2017-06-09T14:34:13Z | |
date available | 2017-06-09T14:34:13Z | |
date copyright | 1996/12/01 | |
date issued | 1996 | |
identifier issn | 0022-4928 | |
identifier other | ams-21887.pdf | |
identifier uri | http://onlinelibrary.yabesh.ir/handle/yetl/4158275 | |
description abstract | Over a 2½-day period beginning 0000 UTC 11 May 1982, 15 mesoscale convective systems (MCSs) developed and moved eastward across the moist axis located over the southern plains of the United States. While the 6?18-h lifetimes of each of these individual MCSs are not sufficiently long to influence the large-scale environment greatly, it is possible that the cumulative effects of the entire group of MCSs can produce significant changes in the large-scale flow patterns. This hypothesis is investigated using output from two runs of a sophisticated mesoscale model. One run includes the effects of convection, and the other does not. Results indicate that in low levels, the inflow of warm, moist air into the convective region is increased when convection is allowed in the model, enhancing the likelihood that convection will continue and thereby acting as a positive feedback mechanism. In upper levels, the convection acts as a Rossby wave source region and produces significant upper-level perturbations that cover at least 50° longitude spread. Convective effects also influence cyclogenesis since the MCSs strengthen the low-level baroclinicity and modify the phase relationship between pressure and thermal waves in the midlevels. Thus, it is clear that the effects of a persistent, mesoscale region of convection on the large-scale environment are substantial. | |
publisher | American Meteorological Society | |
title | Effects of Persistent, Midlatitude Mesoscale Regions of Convection on the Large-Scale Environment during the Warm Season | |
type | Journal Paper | |
journal volume | 53 | |
journal issue | 23 | |
journal title | Journal of the Atmospheric Sciences | |
identifier doi | 10.1175/1520-0469(1996)053<3503:EOPMMR>2.0.CO;2 | |
journal fristpage | 3503 | |
journal lastpage | 3527 | |
tree | Journal of the Atmospheric Sciences:;1996:;Volume( 053 ):;issue: 023 | |
contenttype | Fulltext |