Thursday, 7 August 2003: 4:09 PM
On the Use of a Coastal Mesonet to Reveal Anomalous Mesoscale Flows in Weakly-Forced Synoptic Conditions
The Sea Port of Debarkation (SPOD) Vulnerability and Ship Protection in the Littoral Region Weather Model Experiment was conducted during the summer of 2001 on the lower Chesapeake Bay. The primary goal of the experiment was to measure the improvement in the prediction of weakly forced mesoscale circulations in a littoral region based on an increased spatio-temporal resolution of surface characteristics. Historically, the primary mesoscale flow feature prevalent during periods of weak synoptics is the sea breeze. The sea breeze circulation typifies the type of mesoscale feature that could be modeled more accurately with improved spatio-temporal input data streams. For example, a higher temporal resolution soil moisture data set would reveal the areas in which incident short-wave radiation can be used more efficiently for direct heating of land surfaces, which in turn sets up a greater cross-coast temperature gradient yielding a stronger sea breeze. Another important result from this experiment was that the spatially dense mesonet revealed other anomalous flows in which modeling efforts either completely failed to detect or struggled to model the proper spatial and/or temporal properties. Two of these events will be examined. The first is a nocturnal accelerated south to southwest flow that quickly blossoms over open waters of the bay. The 2nd is a tidally aided drop in wind speeds, most prevalent during daylight hours at certain locations. Examples of each of these flows will be shown with special emphasis their on the spatial and temporal properties.