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- Author or Editor: Ronald L. Lavoie x
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Abstract
A single-layer mesoscale model, originally developed for the study of wintertime take-effect storms, is applied to the airflow over the Island of Oahu, Hawaii. Terrain effects, land roughness, island heating, and surface evaporation are all included. Convective precipitation and latent heating are parameterized in terms of larger-scale motions resolved on the 3-km × 3-km grid.
Experiments were conducted with an atmospheric structure consistent with typical trade conditions as well as with variations from normal wind speed and inversion height. Satisfactory agreement was achieved with observed patterns of inversion height, cloud base height, temperature, relative humidity, wind flow, and precipitation under typical conditions. Mixing of dry air through the inversion from above was deduced to be very important. In most experiments the model generated a hydraulic jump to the lee of the mountains. Sea breeze effects were only partially simulated. Under some conditions the blocking effect of the Island in the model resulted in less than 40% of the upstream air surmounting the central part of the windward mountain ridge, so that vertical cross-section models are contraindicated.
Abstract
A single-layer mesoscale model, originally developed for the study of wintertime take-effect storms, is applied to the airflow over the Island of Oahu, Hawaii. Terrain effects, land roughness, island heating, and surface evaporation are all included. Convective precipitation and latent heating are parameterized in terms of larger-scale motions resolved on the 3-km × 3-km grid.
Experiments were conducted with an atmospheric structure consistent with typical trade conditions as well as with variations from normal wind speed and inversion height. Satisfactory agreement was achieved with observed patterns of inversion height, cloud base height, temperature, relative humidity, wind flow, and precipitation under typical conditions. Mixing of dry air through the inversion from above was deduced to be very important. In most experiments the model generated a hydraulic jump to the lee of the mountains. Sea breeze effects were only partially simulated. Under some conditions the blocking effect of the Island in the model resulted in less than 40% of the upstream air surmounting the central part of the windward mountain ridge, so that vertical cross-section models are contraindicated.
The modernization of the National Weather Service (NWS) will provide new datasets along with advanced technological capabilities that will enhance our understanding of meteorological and hydrological processes. Improved local warning and forecast techniques should flow from this new understanding. The knowledge transfer to improved services can be greatly accelerated by local partnerships with universities and others in the scientific community. Hence, a key objective of the modernization and associated restructuring of the NWS is to stimulate collaborative research activities among weather forecast offices, river forecast centers, universities, and others in the scientific community. This article describes steps the NWS is taking to improve opportunities for collaboration.
The modernization of the National Weather Service (NWS) will provide new datasets along with advanced technological capabilities that will enhance our understanding of meteorological and hydrological processes. Improved local warning and forecast techniques should flow from this new understanding. The knowledge transfer to improved services can be greatly accelerated by local partnerships with universities and others in the scientific community. Hence, a key objective of the modernization and associated restructuring of the NWS is to stimulate collaborative research activities among weather forecast offices, river forecast centers, universities, and others in the scientific community. This article describes steps the NWS is taking to improve opportunities for collaboration.
