Long-Term Simulations of Thermally Driven Flows and Orographic Convection at Convection-Parameterizing and Cloud-Resolving ResolutionsSource: Journal of Applied Meteorology and Climatology:;2013:;volume( 052 ):;issue: 006::page 1490DOI: 10.1175/JAMC-D-12-0167.1Publisher: American Meteorological Society
Abstract: he purpose of this paper is to validate the representation of topographic flows and moist convection over the European Alps in a convection-parameterizing simulation (CPM; ?x = 6.6 km) and two cloud-resolving simulations (CRM; ?x = 1.1 and 2.2 km). All simulations and further sensitivity experiments are validated against a large set of observations for an 18-day fair-weather summer period. The episode considered is characterized by pronounced plain?valley pressure gradients, strong daytime upvalley flows, and weak nighttime down-valley flows. In addition, convective precipitation is recorded during the late afternoon and is preceded by a phase of shallow convection. The observed transition from shallow to deep convection occurs within a 3-h period. The results indicate good agreement between both CRMs and the observed diurnal evolution in terms of near-surface winds, cloud formation, and precipitation. The differences between the two CRMs are surprisingly small. In contrast, the CPM produces too-early peaks of cloud cover and precipitation that are due to a too-early activation of deep convection. Detailed sensitivity experiments show that the convection scheme, rather than the underresolved small-scale topography, is responsible for the poor performance of the CPM. In addition, observations and simulations show that late-morning mass convergence does not correlate with afternoon precipitation. Rather, it is found that enhanced convective activity is related to increased conditional instability.
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contributor author | Langhans, Wolfgang | |
contributor author | Schmidli, Juerg | |
contributor author | Fuhrer, Oliver | |
contributor author | Bieri, Susanne | |
contributor author | Schär, Christoph | |
date accessioned | 2017-06-09T16:49:15Z | |
date available | 2017-06-09T16:49:15Z | |
date copyright | 2013/06/01 | |
date issued | 2013 | |
identifier issn | 1558-8424 | |
identifier other | ams-74723.pdf | |
identifier uri | http://onlinelibrary.yabesh.ir/handle/yetl/4216980 | |
description abstract | he purpose of this paper is to validate the representation of topographic flows and moist convection over the European Alps in a convection-parameterizing simulation (CPM; ?x = 6.6 km) and two cloud-resolving simulations (CRM; ?x = 1.1 and 2.2 km). All simulations and further sensitivity experiments are validated against a large set of observations for an 18-day fair-weather summer period. The episode considered is characterized by pronounced plain?valley pressure gradients, strong daytime upvalley flows, and weak nighttime down-valley flows. In addition, convective precipitation is recorded during the late afternoon and is preceded by a phase of shallow convection. The observed transition from shallow to deep convection occurs within a 3-h period. The results indicate good agreement between both CRMs and the observed diurnal evolution in terms of near-surface winds, cloud formation, and precipitation. The differences between the two CRMs are surprisingly small. In contrast, the CPM produces too-early peaks of cloud cover and precipitation that are due to a too-early activation of deep convection. Detailed sensitivity experiments show that the convection scheme, rather than the underresolved small-scale topography, is responsible for the poor performance of the CPM. In addition, observations and simulations show that late-morning mass convergence does not correlate with afternoon precipitation. Rather, it is found that enhanced convective activity is related to increased conditional instability. | |
publisher | American Meteorological Society | |
title | Long-Term Simulations of Thermally Driven Flows and Orographic Convection at Convection-Parameterizing and Cloud-Resolving Resolutions | |
type | Journal Paper | |
journal volume | 52 | |
journal issue | 6 | |
journal title | Journal of Applied Meteorology and Climatology | |
identifier doi | 10.1175/JAMC-D-12-0167.1 | |
journal fristpage | 1490 | |
journal lastpage | 1510 | |
tree | Journal of Applied Meteorology and Climatology:;2013:;volume( 052 ):;issue: 006 | |
contenttype | Fulltext |