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- Author or Editor: Keith L. Seitter x
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Abstract
A new form of the density current speed equation is presented which uses the surface pressure rise to predict the speed of the current front. This allows the speed prediction to be made with only surface measured quantities. This form of the equation is tested on gust front observations and numerical density current simulations and found to give good results.
A simple, moist numerical model is used to simulate dry density currents and moist currents which produce an arc/rop cloud. The numerical results provide information on the lifting associated with density current passage and the forced updraft velocities at the front, and also show that use of the pressure form of the density current speed equation is especially important when condensation is occurring above the density current.
Abstract
A new form of the density current speed equation is presented which uses the surface pressure rise to predict the speed of the current front. This allows the speed prediction to be made with only surface measured quantities. This form of the equation is tested on gust front observations and numerical density current simulations and found to give good results.
A simple, moist numerical model is used to simulate dry density currents and moist currents which produce an arc/rop cloud. The numerical results provide information on the lifting associated with density current passage and the forced updraft velocities at the front, and also show that use of the pressure form of the density current speed equation is especially important when condensation is occurring above the density current.
Abstract
It is common when speaking colloquially to describe climate as the average weather, which implies weather is the driver and climatic averages are a passive by-product of it, but it is useful to reframe this toward weather being the “expression” of climate. That is, a region’s climate defines the range of weather it might experience (including the extent and frequency of extremes). In this framing, weather is driven by a region’s climate. A changing climate then, necessarily, is experienced as a change in local weather events—often most visibly through changes in the extent or frequency of extreme weather.
Abstract
It is common when speaking colloquially to describe climate as the average weather, which implies weather is the driver and climatic averages are a passive by-product of it, but it is useful to reframe this toward weather being the “expression” of climate. That is, a region’s climate defines the range of weather it might experience (including the extent and frequency of extremes). In this framing, weather is driven by a region’s climate. A changing climate then, necessarily, is experienced as a change in local weather events—often most visibly through changes in the extent or frequency of extreme weather.
Abstract
The structure of squall-line type thunderstorms is investigated with special emphasis on the upshear sloping updraft which is often observed in these storms. To aid in the investigation, a new version of the convective Richardson number is formed which adds the negative buoyancy due to liquid water loading to the thermal buoyancy of the lifted parcel in the calculation of the buoyant energy. This modified convective Richardson number is easily calculated using a pre-storm sounding and has predictive value for thunderstorm type.
While it is widely accepted that the updraft's upshear slope is caused by the ascending parcels partially conserving their horizontal momentum toward the rear of the storm, this paper presents a new theory for the production of this slope. In this theory, the vorticity production due to the liquid water distribution leads to an upshear slope of the updraft/downdraft interface. A stable slope is reached when the loading mechanism is balanced by the forces exerted by the environmental shear.
A two-dimensional numerical model is developed which is shown to be capable of reproducing many of the observed features of squall-line type thunderstorms, including the upshear sloping updraft. The internal structure of these storms is investigated with both Boussinesq and anelastic versions of the model. Through comparative simulations, the importance of liquid water loading and evaporative cooling is demonstrated.
Abstract
The structure of squall-line type thunderstorms is investigated with special emphasis on the upshear sloping updraft which is often observed in these storms. To aid in the investigation, a new version of the convective Richardson number is formed which adds the negative buoyancy due to liquid water loading to the thermal buoyancy of the lifted parcel in the calculation of the buoyant energy. This modified convective Richardson number is easily calculated using a pre-storm sounding and has predictive value for thunderstorm type.
While it is widely accepted that the updraft's upshear slope is caused by the ascending parcels partially conserving their horizontal momentum toward the rear of the storm, this paper presents a new theory for the production of this slope. In this theory, the vorticity production due to the liquid water distribution leads to an upshear slope of the updraft/downdraft interface. A stable slope is reached when the loading mechanism is balanced by the forces exerted by the environmental shear.
A two-dimensional numerical model is developed which is shown to be capable of reproducing many of the observed features of squall-line type thunderstorms, including the upshear sloping updraft. The internal structure of these storms is investigated with both Boussinesq and anelastic versions of the model. Through comparative simulations, the importance of liquid water loading and evaporative cooling is demonstrated.
Abstract
An explicit solution is derived for the trajectory of a particle in an inertial flow on a rotating sphere. This solution explains many of the features of inertial trajectories that have been presented in the literature.
Abstract
An explicit solution is derived for the trajectory of a particle in an inertial flow on a rotating sphere. This solution explains many of the features of inertial trajectories that have been presented in the literature.
Abstract
Abstract not available.
Abstract
Abstract not available.
Abstract
Observations are presented of a cold front which passed over the Florida peninsula and produced a rope cloud visible on satellite imagery. The low level structure of the leading edge of the front is revealed with data from the 150 m tower at Cape Canaveral Air Force Station. It is shown that the leading edge of the front is very similar to thunderstorm gust fronts and the speed is predicted well by the gust front speed equation. This indicates that the rope cloud is directly analogous to the arc cloud sometimes observed along thunderstorm gust fronts. Further, the rope cloud appears to be a less intense manifestation of the forced convection that produces the narrow cold‐frontal rainbands observed in some other cold front studies.
Abstract
Observations are presented of a cold front which passed over the Florida peninsula and produced a rope cloud visible on satellite imagery. The low level structure of the leading edge of the front is revealed with data from the 150 m tower at Cape Canaveral Air Force Station. It is shown that the leading edge of the front is very similar to thunderstorm gust fronts and the speed is predicted well by the gust front speed equation. This indicates that the rope cloud is directly analogous to the arc cloud sometimes observed along thunderstorm gust fronts. Further, the rope cloud appears to be a less intense manifestation of the forced convection that produces the narrow cold‐frontal rainbands observed in some other cold front studies.
Abstract
Over the past century, the atmospheric and related sciences have seen incredible advances in our understanding of Earth’s environment and our ability to monitor and predict its behavior. These advances have had a profound impact on society and have been integrated into every aspect of daily life. The American Meteorological Society (AMS) has been instrumental in supporting these advances throughout its first 100 years of existence as a scientific and professional society serving the community of professionals in the atmospheric and related oceanic and hydrologic sciences. AMS has provided opportunities for researchers and practitioners to share their scientific findings and build fruitful collaborations to further the science and its application. Through strategic initiatives at key points in its history, AMS has pushed the science forward—highlighting areas ripe for development, creating frameworks for interdisciplinary interactions, and providing innovative approaches to the dissemination of research results. As a society made up of the scientific community and led by many of the most prominent scientists of their time, AMS has been able to respond to, and often anticipate, the needs of its community.
Abstract
Over the past century, the atmospheric and related sciences have seen incredible advances in our understanding of Earth’s environment and our ability to monitor and predict its behavior. These advances have had a profound impact on society and have been integrated into every aspect of daily life. The American Meteorological Society (AMS) has been instrumental in supporting these advances throughout its first 100 years of existence as a scientific and professional society serving the community of professionals in the atmospheric and related oceanic and hydrologic sciences. AMS has provided opportunities for researchers and practitioners to share their scientific findings and build fruitful collaborations to further the science and its application. Through strategic initiatives at key points in its history, AMS has pushed the science forward—highlighting areas ripe for development, creating frameworks for interdisciplinary interactions, and providing innovative approaches to the dissemination of research results. As a society made up of the scientific community and led by many of the most prominent scientists of their time, AMS has been able to respond to, and often anticipate, the needs of its community.
