The use of mesoscale numerical models to assess wind distribution and boundary-layer structure in complex terrain

Pielke, Roger A.

doi:10.1007/bf00120893

Cited by 12 publications

(5 citation statements)

References 30 publications

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“…Thus, a katabatic flow ranking system was employed. Throughout the observational period, there exist nights where synoptic or mountain wave forcing completely flushes katabatic winds from a slope or canyon (Pielke 1985;Lee et al 1987;Lee et el. 1989;Clark et el.…”

Section: A Flow Characterizationmentioning

confidence: 99%

The Interaction of Katabatic Flow and Mountain Waves. Part I: Observations and Idealized Simulations

Poulos¹,

Bossert²,

McKee³

et al. 2000

J. Atmos. Sci.

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The mutual interaction of katabatic flow in the nocturnal boundary layer (NBL) and topographically forced gravity waves is investigated. Due to the nonlinear nature of these phenomena, analysis focuses on information obtained from the 1993 Atmospheric Studies in Complex Terrain field program held at the mountain-canyonplains interface near Eldorado Canyon, Colorado, and idealized simulations. Perturbations to katabatic flow by mountain waves, relative to their more steady form in quiescent conditions, are found to be caused by dynamic pressure effects. Based on a local Froude number climatology, case study analysis, and the simulations, the dynamic pressure effect is theorized to occur as gravity wave pressure perturbations are transmitted through the atmospheric column to the surface and, through altered horizontal pressure gradient forcing, to the surface-based katabatic flows. It is proposed that these perturbations are a routine feature in the atmospheric record and represent a significant portion of the variability in complex terrain katabatic flows.The amplitude, wavelength, and vertical structure of mountain waves caused by flow over a barrier are themselves partly determined by the evolving structure of the NBL in which the drainage flows develop. For Froude number Fr Ͼ ϳ0.5 the mountain wave flow is found to separate from the surface at higher altitudes with NBL evolution (increasing time exposed to radiational cooling), as is expected from Fr considerations. However, flow with Fr Ͻ ϳ0.5 behaves unexpectedly. In this regime, the separation point descends downslope with NBL evolution. Overall, a highly complicated, mutually evolving, system of mountain wave-katabatic flow interaction is found, such that the two flow phenomena are, at times, indistinguishable. The mechanisms described here are expanded upon in a companion paper through realistic numerical simulations and analysis of a nocturnal case study (3-4 September 1993).

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Section: A Flow Characterizationmentioning

confidence: 99%

The Interaction of Katabatic Flow and Mountain Waves. Part I: Observations and Idealized Simulations

Poulos¹,

Bossert²,

McKee³

et al. 2000

J. Atmos. Sci.

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“…The numerical weather models listed in Rogers et al (1995), Staudenmaier (1996aStaudenmaier ( -d, 1997a, Mittlestadt (1997) Kalnay et al (1990) National Meteorological Center (1988), Kalnay et al (1990) Bleck & Benjamin (1993, Benjamin et al (1998) Rosmond (1992), Hogan & Brody (1993), Staudenmaier (1997d) Anthes & Warner (1978, Dudhia et al (1999) Pielke (1985, Pielke et al (1992), Cotton et al (1994, 1995) Côté et al (1998) Cullen (1993) Woods (1997 …”

Section: Forecast Techniquesmentioning

confidence: 99%

Weather, climate, and hydrologic forecasting for the US Southwest: a survey

Hartmann¹,

Bales²,

Sorooshian³

2002

Clim. Res.

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As part of a regional integrated assessment of climate vulnerability, a survey was conducted from June 1998 to May 2000 of weather, climate, and hydrologic forecasts with coverage of the US Southwest and an emphasis on the Colorado River Basin. The survey addresses the types of forecasts that were issued, the organizations that provided them, and techniques used in their generation. It reflects discussions with key personnel from organizations involved in producing or issuing forecasts, providing data for making forecasts, or serving as a link for communicating forecasts. During the survey period, users faced a complex and constantly changing mix of forecast products available from a variety of sources. The abundance of forecasts was not matched in the provision of corresponding interpretive materials, documentation about how the forecasts were generated, or reviews of past performance. Potential existed for confusing experimental and research products with others that had undergone a thorough review process, including official products issued by the National Weather Service. Contrasts between the state of meteorologic and hydrologic forecasting were notable, especially in the former's greater operational flexibility and more rapid incorporation of new observations and research products. Greater attention should be given to forecast content and communication, including visualization, expression of probabilistic forecasts and presentation of ancillary information. Regional climate models and use of climate forecasts in water supply forecasting offer rapid improvements in predictive capabilities for the Southwest. Forecasts and production details should be archived, and publicly available forecasts should be accompanied by performance evaluations that are relevant to users. KEY WORDS: Weather forecasts · Climate forecasts · Hydrologic forecasts · US Southwest · Hydrometeorology · HydroclimatologyResale or republication not permitted without written consent of the publisher

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“…The Regional Atmospheric Modeling Systems (RAMS) was developed at Colorado State University (Pielke et al, 1992), by merging advances in modeling dynamic microscale cloud processes (Cotton et al, 1994(Cotton et al, , 1995 with mesoscale models of land-atmosphere interactions (Pielke, 1985). RAMS incorporates the fundamental physics of atmospheric motion, turbulent diffusion, cloud formation and interaction with precipitating liquid and ice, cumulus convection, latent and sensible heat exchange, kinematic terrain effects, multiple soil layers, vegetation, and surface water.…”

Section: Ramsmentioning

confidence: 99%