Marine Atmospheric Boundary-Layer Structure and Air-Sea Fluxes during CBLAST-Low

Meteorological and turbulence measurements were made during CBLAST-Low in the summer of 2003 using the NPS/CIRPAS Pelican aircraft (a modified Cessna 337 with only the pusher engine). The Pelican was instrumented with fast-responding wind, temperature, humidity, IR sea surface temperature and motion and navigation sensors. Eighteen research flights were flown over the area bounded by the southern shore of Martha's Vineyard island (Massachusetts)ans 41°N during the July 30 - August 28, 2003 period. Data were recorded at a rate of 40 Hz for eddy correlation flux calculations.

Results of air-sea fluxes and boundary layer structure measurements from select flights are presented. One of the findings is the highly non-homogeneous SST which exhibited gradients of over 6 °C at edges of cool water pools with a sign reversal of the difference between SST and ambient temperature. Data from repeated low level runs across such fronts showed a dramatic response of the overlaying air to the sudden change in the surface forcing. Fluctuations of vertical wind, temperature and humidity were found about 5 times greater over the warmer side of the gradient compared to those on the colder side.