Horizontal variability of the marine boundary layer structure upwind of San Nicolas Island during program FIRE, 1987

Abstract

The Naval Ocean Systems Center airborne platform was utilized during research project FIRE (First International Satellite Cloud Climatology Project Regional Experiment) to investigate the low level horizontal variability ofthe marine boundary layer structure. Flights were made near San Nicolas Island to determine how well island-based measurements represent upwind open ocean conditions. The meteorological profiles revealed differences between the open ocean conditions and those taken near the island. The observed differences were not uniquely tied to a specific island effect since the upwind fluctuations bounded the island measurements. A higher concentration of surface-based aerosols existed around the island, and if the resulting extinction parameter were used to model open ocean ship-to-ship electro-optical propagation conditions, errors would result. This is not so for vertical ship-to-satellite propagation since the total integrated vertical optical depths as measured at the island are not significantly affected by the shallow surface-based aerosol layer. Sea surface and cloud top temperatures taken near the island are not always representative of those observed upwind.