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This study uses the new satellite-based Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) mission to retrieve tropospheric profiles of temperature and moisture over the data-sparse eastern Pacific Ocean. The COSMIC retrievals, which employ a global positioning system radio occultation technique combined with “first-guess” information from numerical weather prediction model analyses, are evaluated through the diagnosis of an intense atmospheric river (AR; i.e., a narrow plume of strong water vapor flux) that devastated the Pacific Northwest with flooding rains in early November 2006. A detailed analysis of this AR is presented first using conventional datasets and highlights the fact...
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With a new automated precipitation collector we measured a remarkable decrease of 51‰ in the hydrogen isotope ratio (δ 2H) of precipitation over a 60-minute period during the landfall of an extratropical cyclone along the California coast on 21 March 2005. The rapid drop in δ 2H occurred as precipitation generation transitioned from a shallow to a much deeper cloud layer, in accord with synoptic-scale ascent and deep “seeder-feeder” precipitation. Such unexpected δ 2H variations can substantially impact widely used isotope-hydrograph methods. From extreme δ 2H values of −26 and −78‰, we calculate precipitation temperatures of 9.7 and −4.2°C using an adiabatic condensation isotope model, in good agreement with temperatures...
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With a new automated precipitation collector we measured a remarkable decrease of 51‰ in the hydrogen isotope ratio (δ 2H) of precipitation over a 60-minute period during the landfall of an extratropical cyclone along the California coast on 21 March 2005. The rapid drop in δ 2H occurred as precipitation generation transitioned from a shallow to a much deeper cloud layer, in accord with synoptic-scale ascent and deep “seeder-feeder” precipitation. Such unexpected δ 2H variations can substantially impact widely used isotope-hydrograph methods. From extreme δ 2H values of −26 and −78‰, we calculate precipitation temperatures of 9.7 and −4.2°C using an adiabatic condensation isotope model, in good agreement with temperatures...
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The pre-cold-frontal low-level jet within oceanic extratropical cyclones represents the lower-tropospheric component of a deeper corridor of concentrated water vapor transport in the cyclone warm sector. These corridors are referred to as atmospheric rivers (ARs) because they are narrow relative to their length scale and are responsible for most of the poleward water vapor transport at midlatitudes. This paper investigates landfalling ARs along adjacent north- and south-coast regions of western North America. Special Sensor Microwave Imager (SSM/I) satellite observations of long, narrow plumes of enhanced integrated water vapor (IWV) were used to detect ARs just offshore over the eastern Pacific from 1997 to 2005....
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