జర్నల్ ఆఫ్ కోస్టల్ జోన్ మేనేజ్‌మెంట్

నైరూప్య

Evaluation of Photosynthetically Available Radiation Algorithm in the Southeastern Brazilian Margin

Joao Felipe Cardoso dos Santos and Milton Kampel

Photosynthetically available radiation (PAR) comprises the integrated irradiance between 400–700 nm which reaches the sea surface. Its importance in the marine environment is directly related to primary productivity, which uses light in the atmospheric carbon assimilation reactions. The algorithm for estimating PAR with SeaWiFS, MODIS and MERIS data was evaluated in relation to in situ measurements during the summer and winter of 2001 and 2002. Statistical analyses indicated a systematic error with all three sensors estimates overestimating the in situ measurements with a bias equal to 1.63, 1.53 and 1.64 Einstein m-2 d -1 and a percentage error equal to 3.95%, 4.13% and 4.54%, respectively for SeaWiFS, MODIS and MERIS. A Generalized Linear Model (GLM) was adjusted for all sensors decreasing bias and percentage error to values close to zero. The best performance after adjusting was observed with MODIS data followed by SeaWiFS and MERIS, consecutively. Overall, the satellite estimations of PAR showed a good correlation with the in situ measurements and the linear adjustments corrected the observed systematic error.