Application of Theory to Simulations of Observed Cases of Orographically Forced Convective RainfallSource: Monthly Weather Review:;2012:;volume( 140 ):;issue: 009::page 3039DOI: 10.1175/MWR-D-11-00253.1Publisher: American Meteorological Society
Abstract: n two recent papers, the authors reported on numerical simulations of conditionally unstable flows past an idealized mesoscale mountain ridge. These idealized simulations, which were performed with a three-dimensional, explicitly cloud-resolving model, allowed the investigation of simulated precipitation characteristics as a function of the prescribed environment. The numerical solutions were carried out for a uniform wind flowing past a bell-shaped ridge and using an idealized unstable sounding with prescribed values of the relevant parameters.In the present work the application of these theoretical results to observed cases of orographically forced convective rainfall including the Big Thompson flood (1976, Colorado), the Oahu flood (1974, Hawaii), and the Gard flood (2002, France) is reported. Specifically, numerical simulations have been carried out using observed and idealized soundings relevant to these cases but with idealized topography. It is found that using the observed soundings, but with idealized constant-wind profiles, the simulated rain rates fit reasonably well within the previous theoretically derived parameter space for intense orographic convective rainfall. However, in order to reproduce larger rainfall rates, in closer agreement with observations, in the first two cases it was necessary to initialize the sounding with a wind profile characterized by low-level flow toward the mountain with weak flow aloft (as observed for the across-mountain wind component). For the Gard case, the situation was more complex and it is found unlikely that the situation can be reduced to a simple two-dimensional problem.
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contributor author | Miglietta, Mario Marcello | |
contributor author | Rotunno, Richard | |
date accessioned | 2017-06-09T17:29:42Z | |
date available | 2017-06-09T17:29:42Z | |
date copyright | 2012/09/01 | |
date issued | 2012 | |
identifier issn | 0027-0644 | |
identifier other | ams-86244.pdf | |
identifier uri | http://onlinelibrary.yabesh.ir/handle/yetl/4229781 | |
description abstract | n two recent papers, the authors reported on numerical simulations of conditionally unstable flows past an idealized mesoscale mountain ridge. These idealized simulations, which were performed with a three-dimensional, explicitly cloud-resolving model, allowed the investigation of simulated precipitation characteristics as a function of the prescribed environment. The numerical solutions were carried out for a uniform wind flowing past a bell-shaped ridge and using an idealized unstable sounding with prescribed values of the relevant parameters.In the present work the application of these theoretical results to observed cases of orographically forced convective rainfall including the Big Thompson flood (1976, Colorado), the Oahu flood (1974, Hawaii), and the Gard flood (2002, France) is reported. Specifically, numerical simulations have been carried out using observed and idealized soundings relevant to these cases but with idealized topography. It is found that using the observed soundings, but with idealized constant-wind profiles, the simulated rain rates fit reasonably well within the previous theoretically derived parameter space for intense orographic convective rainfall. However, in order to reproduce larger rainfall rates, in closer agreement with observations, in the first two cases it was necessary to initialize the sounding with a wind profile characterized by low-level flow toward the mountain with weak flow aloft (as observed for the across-mountain wind component). For the Gard case, the situation was more complex and it is found unlikely that the situation can be reduced to a simple two-dimensional problem. | |
publisher | American Meteorological Society | |
title | Application of Theory to Simulations of Observed Cases of Orographically Forced Convective Rainfall | |
type | Journal Paper | |
journal volume | 140 | |
journal issue | 9 | |
journal title | Monthly Weather Review | |
identifier doi | 10.1175/MWR-D-11-00253.1 | |
journal fristpage | 3039 | |
journal lastpage | 3053 | |
tree | Monthly Weather Review:;2012:;volume( 140 ):;issue: 009 | |
contenttype | Fulltext |