AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Chlorophyll-a and Other Ocean Color Products as Predictive Tools of the Organic Mass Fraction in Submicron Sea Spray
MATTEO RINALDI, Sandro Fuzzi, Stefano Decesari, Salvatore Marullo, Rosalia Santoleri, Antonello Provenzale, Jost von Hardenberg, Darius Ceburnis, Colin O'Dowd, M. Cristina Facchini, CNR-ISAC
Abstract Number: 109 Working Group: Remote and Regional Atmospheric Aerosols
Abstract Initial efforts towards developing a combined organic-inorganic sea-spray source function parameterization for large-scale models utilized chlorophyll-a and wind speed as input parameters to combine oceanic biology and atmospheric dynamics. These first studies, performed using satellite derived chlorophyll-a fields with low temporal resolution (monthly averages), reported only a modest correlation coefficient (at best 0.55) between Chlorophyll-a and organic matter enrichment in sea-spray, suggesting that Chlorophyll-a is only partially suitable for this aim.
In order to check if better biological activity surrogates are available from satellite measurements, the following research activity has been carried on, using aerosol data collected at Mace Head research station (Ireland) and satellite ocean color products from ESA GlobCOLOUR. A reconstructed Chlorophyll-a field of the North-Atlantic Ocean, based on daily data, revealed an improved correlation of 0.73 between the fractional mass contribution of organics in sea-spray and chlorophyll-a concentration. A similar analysis, using “colored dissolved and detrital organic materials absorption” and “particulate organic carbon” concentration, revealed slightly lower correlation coefficients (0.70 and 0.69). These results indicate that, to date, chlorophyll-a is the best biological surrogate for predicting sea-spray organic enrichment. In fact, considering the minimal difference between the correlation coefficients obtained with the three ocean color products, there is no reason to substitute chlorophyll-a, which is the most accurate parameter obtained from ocean color data, with other biological surrogates which in general can be affected by larger and less known errors.
A new relationship describing the organic enrichment of sea spray aerosol, as a function of both wind speed and sea surface chlorophyll-a concentration, to be implemented in large scale models, is proposed as a conclusion of this study.