An airborne, real aperture radar study of the Chesapeake Bay outflow plume
| Autor: | Mark A. Sletten, David J. McLaughlin, Tim F. Donato, E. Twarog, George O. Marmorino |
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| Rok vydání: | 1999 |
| Předmět: |
Atmospheric Science
Soil Science Aquatic Science Oceanography law.invention Geochemistry and Petrology law Earth and Planetary Sciences (miscellaneous) Panache Bathymetry Radar Earth-Surface Processes Water Science and Technology geography geography.geographical_feature_category Ecology Front (oceanography) Paleontology Forestry Estuary Geodesy Plume Geophysics Space and Planetary Science Outflow Bay Geology |
| Zdroj: | Journal of Geophysical Research: Oceans. 104:1211-1222 |
| ISSN: | 0148-0227 |
| DOI: | 10.1029/1998jc900034 |
| Popis: | An airborne, real aperture radar (RAR) has been used to study the fronts associated with the Chesapeake Bay outflow plume during spring outflow conditions. The RAR produced images of the ocean surface with a range resolution of 10 m, an azimuthal resolution of approximately 30 m, and an image size of 2.5 km × 24 km. Two sampling strategies were utilized: one to synoptically map the entire mouth of the Chesapeake Bay at roughly hourly intervals; and a second to capture the rapid evolution of particular features. In addition, flight times were chosen such that over the course of the entire experiment, data were collected over all phases of the semidiurnal tidal cycle. Three distinct frontal signatures were observed in the imagery. A primary front extended from inside the estuary along the Chesapeake Channel to an anticyclonic turning region east of Cape Henry, and then extended southward along the coast toward Cape Hatteras. This is the classic expression of the plume front, inertial turning region, and coastal jet. A second front with a north-south orientation was observed approximately 20 km east of the bay mouth. This secondary front appears to mark the residual offshore density gradient. A third front was identified east and south of Cape Henry, within 2 km of the coast. This front appears to mark the inshore edge of the plume and has not been documented previously. Time sequences of the imagery indicate that when moving in a clockwise sense around the primary front, the frontal translation speed varies systematically from 20 cm/s in the northern section to 50 cm/s in the south. The position of the primary front and the locations and trajectories of small-scale frontal cusps suggest that bathymetry may be both a significant determinant of the front location as well as a source of along-front variability. These observations are possible due to the airborne RAR's ability to collect high-frame rate image sequences, a capability that is not shared by present space-based radar systems. |
| Databáze: | OpenAIRE |
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