在珠江口海域海洋光学浮标实验期间获取了赤潮生消过程的水体光学数据和相应的生化数据。利用该实验数据开展了准分析算法(quasi-analytical algorithm,QAA)反演赤潮水体固有光学参数的精度检验和模型修正工作。(1)利用遥感反射率和QAA反演主要水色波段(412,443,490,510,560,620和665 nm)固有光学量发现:在490~665 nm波段水体总吸收系数和颗粒物后向散射系数的反演误差优于25%,在443 nm波段总吸收系数和颗粒物后向散射系数反演误差为8%~32%,在412 nm波段总吸收系数和颗粒物后向散射系数反演误差为31%~57%;浮游植物吸收系数和黄色物质与碎屑吸收系数反演误差分别为32%~157%和59%~80%。对比两种参考波段(555和640 nm)选取方式发现,除490和510 nm外,QAA-640在其他波段的反演精度均优于QAA-555,其中在412和443 nm波段尤为明显。(2)利用实测数据对QAA进行了修正:对于总吸收系数和颗粒物后向散射系数,QAA-555修正算法的反演精度有不同程度的提高,误差减小了1%~11%,QAA-640修正算法的反演精度在412,620和665 nm波段有所提高;对于浮游植物吸收系数和黄色物质与碎硝屑吸收系数,修正算法的反演精度没有明显改善。除412和443 nm波段外,修正的QAA-555均优于修正的QAA-640。(3)利用现场实测总吸收系数数据和QAA反演浮游植物吸收系数和黄色物质与碎屑吸收系数,误差均优于24%;分析算法的误差敏感性发现当对总吸收系数引入20%的误差时,黄色物质与碎屑吸收系数反演误差波动不明显(〈33%),而浮游植物吸收系数在560~665 nm波段反演误差波动可在58%~241%。
In optical buoy experiments in the Zhujiang River mouth regions,the time series of biooptical data of the red tide were obtained.Using these data,retrieving inherent optical parameters of the red tide were carried out with a semianalytical algorithm,and the model was tested,validated and modified with in situ data.(1) In the retrieval of inherent optical properties at major satellite ocean color bands(412,443,490,510,560,620 and 665 nm)with rrs and QAA(quasianalytical algorithm),the errors for total absorption coefficient at and particle backscattering coefficient bbp at 490~665 nm are less than 25%.The errors for at and bbp at 443 nm are about 8%~32%,and about 31%~57% at 412 nm.The error ranges for phytoplankton pigment absorption aph,detritus and colored dissolved organic matter absorption adg are 32%~157% and 59%~80%,respectively.Comparing retrieval result by different reference wavelengths(555 and 640 nm) of QAA,it is found that with the exception of 490 and 510 nm,QAA-640 is better than QAA-555 at other bands,especially at 412 and 443 nm.(2) QAA is modified by in situ data.Modified QAA-555 model derives better at and bbp.The errors decrease by 1%~11%.Modified QAA-640 returns better at and bbp at 412,620 and 665 nm.For aph and adg,the accuracy of retrieval results has no significant improvement.With the exception of 412 and 443 nm,the modified QAA-555 is better than the modified QAA-640.(3)Using QAA to retrieve aph and adg from in situ measured at,the errors are less than 24%;when adding 20% errors to the in situ at,the retrieval error for adg has no significant changes(33%),but the errors of aph fluctuate in the range of 58%~241% at 560~665 nm.