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contributor authorLeMone, Margaret A.
contributor authorChen, Fei
contributor authorTewari, Mukul
contributor authorDudhia, Jimy
contributor authorGeerts, Bart
contributor authorMiao, Qun
contributor authorCoulter, Richard L.
contributor authorGrossman, Robert L.
date accessioned2017-06-09T16:32:17Z
date available2017-06-09T16:32:17Z
date copyright2010/03/01
date issued2009
identifier issn0027-0644
identifier otherams-69607.pdf
identifier urihttp://onlinelibrary.yabesh.ir/handle/yetl/4211295
description abstractFair-weather data along the May?June 2002 International H2O Project (IHOP_2002) eastern track and the nearby Argonne Boundary Layer Experiments (ABLE) facility in southeast Kansas are compared to numerical simulations to gain insight into how the surface influences convective boundary layer (CBL) structure, and to evaluate the success of the modeling system in replicating the observed behavior. Simulations are conducted for 4 days, using the Advanced Research version of the Weather Research and Forecasting (WRF) model coupled to the Noah land surface model (LSM), initialized using the High-Resolution Land Data Assimilation System (HRLDAS). Because the observations focus on phenomena less than 60 km in scale, the model is run with 1-km grid spacing, offering a critical look at high-resolution model behavior in an environment uncomplicated by precipitation. The model replicates the type of CBL structure on scales from a few kilometers to ?100 km, but some features at the kilometer scales depend on the grid spacing. Mesoscale (tens of kilometers) circulations were clearly evident on 2 of the 4 days (30 May and 20 June), clearly not evident on 1 day (22 June), with the situation for the fourth day (17 June) ambiguous. Both observed and modeled surface-heterogeneity-generated mesoscale circulations are evident for 30 May. On the other hand, 20 June satellite images show north-northwest?south-southeast cloud streets (rolls) modulated longitudinally, presumably by tropospheric gravity waves oriented normal to the roll axis, creating northeast?southwest ridges and valleys spaced 50?100 km apart. Modeled cloud streets showed similar longitudinal modulation, with the associated two-dimensional structure having maximum amplitude above the CBL and no relationship to the CBL temperature distribution; although there were patches of mesoscale vertical velocity correlated with CBL temperature. On 22 June, convective rolls were the dominant structure in both model and observations. For the 3 days for which satellite images show cloud streets, WRF produces rolls with the right orientation and wavelength, which grows with CBL depth. Modeled roll structures appeared for the range of CBL depth to Obukhov length ratios (?zi/L) associated with rolls. However, sensitivity tests show that the roll wavelength is also related to the grid spacing, and the modeled convection becomes more cellular with smaller grid spacing.
publisherAmerican Meteorological Society
titleSimulating the IHOP_2002 Fair-Weather CBL with the WRF-ARW–Noah Modeling System. Part II: Structures from a Few Kilometers to 100 km across
typeJournal Paper
journal volume138
journal issue3
journal titleMonthly Weather Review
identifier doi10.1175/2009MWR3004.1
journal fristpage745
journal lastpage764
treeMonthly Weather Review:;2009:;volume( 138 ):;issue: 003
contenttypeFulltext


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