Search Results

You are looking at 1 - 10 of 2,854 items for :

  • Planetary atmospheres x
  • Monthly Weather Review x
  • Refine by Access: Content accessible to me x
Clear All
Raj K. Rai, Larry K. Berg, Branko Kosović, Sue Ellen Haupt, Jeffrey D. Mirocha, Brandon L. Ennis, and Caroline Draxl


Coupled mesoscale–microscale simulations are required to provide time-varying weather-dependent inflow and forcing for large-eddy simulations under general flow conditions. Such coupling necessarily spans a wide range of spatial scales (i.e., ~10 m to ~10 km). Herein, we use simulations that involve multiple nested domains with horizontal grid spacings in the terra incognita (i.e., km) that may affect simulated conditions in both the outer and inner domains. We examine the impact on simulated wind speed and turbulence associated with forcing provided by a terrain with grid spacing in the terra incognita. We perform a suite of simulations that use combinations of varying horizontal grid spacings and turbulence parameterization/modeling using the Weather Research and Forecasting (WRF) Model using a combination of planetary boundary layer (PBL) and large-eddy simulation subgrid-scale (LES-SGS) models. The results are analyzed in terms of spectral energy, turbulence kinetic energy, and proper orthogonal decomposition (POD) energy. The results show that the output from the microscale domain depends on the type of turbulence model (e.g., PBL or LES-SGS model) used for a given horizontal grid spacing but is independent of the horizontal grid spacing and turbulence modeling of the parent domain. Simulation using a single domain produced less POD energy in the first few modes compared to a coupled simulation (one-way nesting) for similar horizontal grid spacing, which highlights that coupled simulations are required to accurately pass the mesoscale features into the microscale domain.

Full access

. INTRODUCTIONThe vertical motions at the earth's surface associatedwith horizontal adow over the mountain ranges are ofimportance both for their direct effect on local climate (e.g.,adiaba:ic warming and cooling with accompanyingcloud aud precipitation formation) and for their indirecteffect on planetary climate by the forcing of stationarywave systems (e.g., Charney and Eliassen 1949). Thisvertical motion is given bywhere V is the vector horizontal wind of which u is theeastward component and v is the

Full access

,hc model will be suit,ablc for the purpose of linear theoretical analysis of thevertical propagation of planetary Iossb>- waves in thc presence of zonal wind shears. Assuming an atmosphere inconstant angular rotation and nssnming westerly zonal wind velocities of thc magnitude of the maximum windsobserved in the midwinter stratosphcric jet, there will always be two or morc planet,ary wave modes that can propa-gate vertically. Thc constant angular wind velocity model is \wed together with t

Full access




-BEE 1955 MONTHLY WESTHER REVIEW 199SOME METEOROLOGICAL ASPECTS OF DROUGHTJFROME NAMIASExtended Forecast Section, U. S. Weather Bureau, Washington, D. C.[Manuscript Received August 4, 19551ABSTliACTThe problem of drought is examined as a manifestation of anomalous patterns of the atmosphere's generalcirculation. Special consideration is given to the quasi-stationary planetary wave ensembles which are responsiblefor extensive summertime drought over the United States. The critical importance of

Full access
Paul J. Neiman, M. A. Shapiro, R. Michael Hardesty, B. Boba Stankov, Rhidian T. Lawrence, Robert J. Zamora, and Tamara Hampel

AUGUST 1988 NEIMAN ET AL. 1671The Pulsed Coherent Doppler Lidar: Observations of Frontal Structure and the Planetary Boundary Layer PAUL J. NEIMANCooperative Institute for Research in Environmental Sciences, University of Colorado/NO/tA, Boulder, ColoradoM. A. SHAPIRO, R. MICHAEL HARDESTY, B. BOBA STANKOV, RHIDIAN T. LAWRENCE,ROBERT J. ZAMORA, AND

Full access

appearing on 30-day mean 700-mb. charts in the North Americanarea during the past 20 winters is described as a useful supplement to the normal chart. Statistics pertaining to thedimensions, symmetry, and motion of planetary waves on these charts are summarized by use of graphical correlationand synoptic models. The results throw light on the structure of the centers of action in the atmosphere and indicatetheir interdependence.CONTENTSPageAbstract_-------------_---_-------_---_---------_---- 203

Full access

a considerable amount of kinetic energy dissi-pated outside the planetary boundary layer, particularly at the jet-stream level. This also may imply that inten-sity of the atmospheric general circulation is significantlv higher than is being assumed in most of the numerical modelsof the atmosphere.1. INTRODUCTIONIn a series- of previous reports (Kung, 1866~~ 19663,1967), studies of the large-scale balance of the kineticenergy in the atmosphere were reported. One of the mainobjectives in this

Full access
Harald Lejenäs and Roland A. Madden

atmosphere and large-scale traveling waveshas been investigated. A 30-yr time series of observational 500-hPa geopotential-height data was used to studythe relation between westward-moving planetary-scale waves I and 2 and blocked flow. It was found that,depending on longitude, 20%-40% of blocks were related to traveling wave 1, whereas the percentage was smallerfor wave 2. The study confirms results of earlier studies that suggest a possible important role for large-scale,westward-moving waves in many

Full access
R. T. Pinker and L. A. Corio

, information regarding this parameter is not available on a routine basis. In thisstudy an attempt is being made to demonstrate that satellite inferred information might be useful for theestimation of radiation budget parameters at the ground surface. Observations from the NOAA 5 satellite wereutilized to relate planetary radiation budget parameters to surface net radiation, over the central United States.The net radiation and the outgoing IR radiation at the top of the atmosphere were found to be

Full access
H. Mark Helfand

change in climate from January to July.They have related deficiencies in the simulation ofthe radiation budget to an incorrect prediction ofthe seasonal trends in planetary albedo and incloudiness. In the present paper, we investigate seasonal trendsin convective cloud cover both in the model and innature and relate these to trends in the specific andrelative humidities of the lower atmosphere. In orderto make the relationship between cumulus convection and humidity more realistic, the cumulus

Full access