Thursday, 13 February 2003: 9:15 AM
Evaluation of coarse mode sea-salt flux parameterizations through shipboard eddy-correlation methods coupled with vertical profile data
During the Rough Evaporation Duct (RED) experiment a Forward Scattering Spectrometer Probe (FSSP) 100 was deployed with rapid response sonic anemometer and IR hygrometer instruments on the R/P Flip. With these instruments eddy-correlation measurements of coarse mode sea salt particles from whitecaps in a subtropical marine environment were performed. Coupled with supplemental data was provided by the CIRPAS Twin Otter research aircraft flying in the area, we developed coarse mode particle budgets for the RED field study. During higher wind periods, positive fluxes of coarse mode salt particles from sea-spray were observed at statistically significant levels. In contrast, during a period when winds were calm and air mass trajectories originated from Hurricane Gill (several thousand kilometers away), a slight downward flux was visible. For the study period we found upward flux values of salt particles for 10 m/s wind speeds that are a factor of two higher than those in the commonly used Smith et al., [1993] algorithm but a factor of two lower than those proposed by Monahan et al., [1986], Andrea et al., [1998], and Reid et al., [2001]. Based on this new data we feel that salt fluxes are known to a factor of 3, rather than previously estimated uncertainties which were on the order of 5 or more.
Lastly, we use this field study as a context for examining salt particle budgets in the sub tropical marine atmosphere. Combined with TRMM satellite precipitation data with mesoscale data from COAMPS, we begin to perform a scale analysis of salt particle budgets for the subtropical pacific basin.
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