Tracking of a Chesapeake Bay estuarine outflow plume with satellite-based ocean color data

Abstract

Estuarine outflow plumes are important coastal processes whose variable nature can make it difficult to monitor using traditional ship-based surveys. This study used multiple ocean color sensors to track an estuarine outflow plume from the Chesapeake Bay in April 2003. Although, no in situ data are available for irrefutable proof, the patterns in ocean color observations in conjunction with meteorological data, strongly suggest that the observed phenomena is in fact an outflow plume. The ocean color data were brought into a geographic information system (GIS), so that various types of spatial analyses could be performed on the plume signature. The observed plume exhibited the typical dynamic response to winds in which the plume narrows and accelerates during downwelling favorable winds, and widens and advects offshore during upwelling favorable winds. Furthermore, area growth, and along- and across-shore frontal speeds of the plume were quantified and compared well to past in situ observations. Differences in the ocean color gradient field of the plume throughout the event were indicative of the expected evolution of the plume structure. This study demonstrates the importance of spatially comprehensive coverage of plume outflow events as well as the suitability of ocean color satellite remote sensing to monitor such events.