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Title: Large eddy simultations of the atmospheric boundary layer east of the Colorado Rockies

Abstract

Large eddy simulation, LES, has often been carried out for the idealized situation of a simple convective boundary layer. Studies of dual Doppler radar and aircraft data from the Phoenix II experiment indicate that the boundary layer of the Colorado High Plains is not a purely convective boundary layer and it is influenced by the mountains to the west. The purpose of this study is to investigate the atmospheric boundary layer on one particular day on the Colorado High Plains. This research applies a LES nested within larger grids, which contain realistic topography and can simulate the larger-scale circulations initiated by the presence of the mountain barrier. How and to what extent the atmospheric boundary layer of the Colorado High Plains is influenced by larger scale circulations and other phenomena associated with the mountain barrier to the west is investigated. The nested grid LES reproduces the characteristics of the atmosphere for the case study day reasonably well. The mountains influence the atmospheric boundary layer over the plains to the east in several ways. The mountains contribute to the vertical shear of the horizontal winds through the thermally-induced mountain-plains circulation. As a consequence of the wind shear, the boundary layer thatmore » develops over the mountains is advected eastward over the top of the plains boundary layer, which is developing separately. This layer is marked by a mixture of gravity waves and turbulence and is atypical of a purely convective boundary layer. Just below this layer, the capping inversion of the plains boundary layer is weak and poorly defined compared to the inversions capping purely convective boundary layers. Gravity waves, triggered by the obstacle of the Rocky Mountains and by convection in the mountain boundary layer, also influence the atmosphere above the Colorado High Plains. These influences are found to have significant effects on the turbulence statistics and the energy spectra.« less

Authors:
;
Publication Date:
Research Org.:
Los Alamos National Lab., NM (United States); Colorado State Univ., Fort Collins, CO (United States). Dept. of Atmospheric Science
Sponsoring Org.:
USDOE, Washington, DC (United States); Department of Defense, Washington, DC (United States)
OSTI Identifier:
10190492
Report Number(s):
LA-SUB-94-140
ON: DE95001748; TRN: 94:009712
DOE Contract Number:  
W-7405-ENG-36
Resource Type:
Technical Report
Resource Relation:
Other Information: DN: Atmospheric Science Paper No. 511; PBD: 22 Oct 1992
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; ROCKY MOUNTAINS; ENVIRONMENTAL EFFECTS; BOUNDARY LAYERS; MATHEMATICAL MODELS; EARTH ATMOSPHERE; TURBULENCE; ENERGY SPECTRA; COLORADO; TOPOGRAPHY; 540110; BASIC STUDIES

Citation Formats

Costigan, K R, and Cotton, W R. Large eddy simultations of the atmospheric boundary layer east of the Colorado Rockies. United States: N. p., 1992. Web. doi:10.2172/10190492.
Costigan, K R, & Cotton, W R. Large eddy simultations of the atmospheric boundary layer east of the Colorado Rockies. United States. doi:10.2172/10190492.
Costigan, K R, and Cotton, W R. Thu . "Large eddy simultations of the atmospheric boundary layer east of the Colorado Rockies". United States. doi:10.2172/10190492. https://www.osti.gov/servlets/purl/10190492.
@article{osti_10190492,
title = {Large eddy simultations of the atmospheric boundary layer east of the Colorado Rockies},
author = {Costigan, K R and Cotton, W R},
abstractNote = {Large eddy simulation, LES, has often been carried out for the idealized situation of a simple convective boundary layer. Studies of dual Doppler radar and aircraft data from the Phoenix II experiment indicate that the boundary layer of the Colorado High Plains is not a purely convective boundary layer and it is influenced by the mountains to the west. The purpose of this study is to investigate the atmospheric boundary layer on one particular day on the Colorado High Plains. This research applies a LES nested within larger grids, which contain realistic topography and can simulate the larger-scale circulations initiated by the presence of the mountain barrier. How and to what extent the atmospheric boundary layer of the Colorado High Plains is influenced by larger scale circulations and other phenomena associated with the mountain barrier to the west is investigated. The nested grid LES reproduces the characteristics of the atmosphere for the case study day reasonably well. The mountains influence the atmospheric boundary layer over the plains to the east in several ways. The mountains contribute to the vertical shear of the horizontal winds through the thermally-induced mountain-plains circulation. As a consequence of the wind shear, the boundary layer that develops over the mountains is advected eastward over the top of the plains boundary layer, which is developing separately. This layer is marked by a mixture of gravity waves and turbulence and is atypical of a purely convective boundary layer. Just below this layer, the capping inversion of the plains boundary layer is weak and poorly defined compared to the inversions capping purely convective boundary layers. Gravity waves, triggered by the obstacle of the Rocky Mountains and by convection in the mountain boundary layer, also influence the atmosphere above the Colorado High Plains. These influences are found to have significant effects on the turbulence statistics and the energy spectra.},
doi = {10.2172/10190492},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1992},
month = {10}
}