Multiyear Observations of Cloud Lines Associated with the Chesapeake and Delaware Bays

Abstract

Satellite and corresponding near-surface in situ observations have been made of single- and dual-band cloud events [dubbed anomalous cloud lines (ACLs)] associated with the Chesapeake and Delaware Bays. A previous study developed the basis for two hypotheses concerning the mechanism responsible for ACLs. One explanation is that ACLs are forced in the same manner as Great Lakes lake-effect midlake cloud lines. An alternate explanation is that at least some ACLs are a special type of ship track that forms in statically unstable marine boundary layers. The time period examined in the current research is January 1997?December 2000. National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer imagery served as the satellite dataset, and NOAA buoy 44009 and Coastal-Marine Automated Network station CHLV2 provided the in situ data. The findings from the satellite portion of this research show that ACLs associated with both the Chesapeake and Delaware Bays were observed on roughly 3% of the days examined and were more frequent during the onset of the cold season. The data also show that single-band ACLs were, in general, more frequent than dual-band ACLs. For the near-surface in situ portion of this research, the average ACL for both bays was associated with a negative air?sea temperature difference and a larger downbay wind component than cross-bay wind component. On a month-by-month basis, ACLs for both bays tended to be associated with abnormally large downbay wind speeds and negative air?sea temperature differences in comparison with the corresponding weighted monthly norms.