基于GOCI数据的黄河口高悬浮物浓度海域的叶绿素a提取指数构建与浓度反演  

Chlorophyll-a Extraction Index Construction and Concentration Inversion Based on GOCI Data in the Yellow River Estuary with High Total Suspended Matter Concentration

作　　者：张曦元 万剑华[1] 刘善伟[1] 宋冬梅[1] ZHANG Xiyuan;WAN Jianhua;LIU Shanwei;SONG Dongmei(College of Oceanography and Space Informatics,China University of Petroleum(East China),Qingdao 266580,China)

机构地区：[1]中国石油大学(华东)海洋与空间信息学院,山东青岛266580

出　　处：《海洋技术学报》2022年第1期20-29,共10页Journal of Ocean Technology

基　　金：国家自然科学基金资助项目(U1906217)。

摘　　要：高浓度悬浮物(TSM)的不透光性干扰了叶绿素(Chl-a)浓度的光谱量测,影响了Chl-a浓度的反演精度。本文以黄河口近岸海域为研究对象,根据最大叶绿素指数(MCI)原理,针对GOCI数据构建叶绿素敏感指数(S_(chl))和悬浮物敏感指数(S_(TSM)),进一步构建了Chl-a提取指数(CEI)以削弱TSM对S_(chl)的影响。采用2011-2018年采集的619组实测Chl-a浓度及同期的GOCI遥感反射率,基于随机森林算法对比多种指数构建的Chl-a浓度反演模型,结果显示:在不分区的情况下,采用CEI构建的Chl-a浓度反演模型的平均相对误差(MRE)为45.9%,其精度结果优于S_(chl)(MRE=49.76%)。为进一步验证CEI在高TSM浓度海域的精度,本文根据波谱斜率(R_(6)-R_(4))/(λ_(6)-λ_(4))将研究区分为Chl-a和TSM主导型水体后,分别构建Chl-a浓度反演模型,研究结果显示:Chl-a主导型水体采用S_(chl)构建的反演模型的MRE为35.81%,TSM主导型水体采用S_(chl)与CEI构建的反演模型的MRE分别为60.39%与36.74%,这也证实了在高TSM浓度海域,采用CEI能够有效削弱TSM对S_(chl)的干扰。The opacity of high concentration of total suspended matter(TSM)interfered with the spectral measurement of chlorophyll-a(Chl-a)concentration,which affected the accuracy of the inversion of Chl-a concentration.This paper takes the coastal waters of the Yellow River estuary as the research area,and constructs Chlorophyll-a sensitivity index(S_(chl))and total suspended matter sensitivity index(S_(TSM))for GOCI data based on the principle of maximum chlorophyll index(MCI),and further constructs the Chl-a extraction index(CEI)to weaken the effect of TSM on S_(chl).Adopting 619 sets of measured Chl-a concentrations collected from 2011 to 2018 and GOCI remote sensing reflectance for the same period,the Chl-a concentration inversion models constructed by several indexes were compared based on random forest algorithm.The results show that the mean relative error(MRE)of the Chl-a concentration inversion model constructed by S_(chl) was 45.9%,and its accuracy was better than that of CEI(MRE=49.76%).In order to further verify the accuracy of CEI in the sea area with high TSM concentration,this paper divides the study area into Chl-a and TSM dominated water bodies according to the spectral slope(R_(6)-R_(4))/(λ_(6)-λ_(4)),and then constructs separate inversion models for Chl-a concentrations.The results show that the MRE of the inversion model construfcted by S_(chl) for Chl-a dominant water body is 35.81%,and the MRE of the inversion model constructed by S_(chl) and CEI for TSM dominant water body is 60.39%and 36.74%respectively which also confirms that the use of CEI is effective in attenuating TSM interference with S_(chl) in waters with high TSM concentrations.

关 键 词：叶绿素a浓度反演 叶绿素a提取指数 GOCI 黄河口近岸海域 

分 类 号：P229[天文地球—大地测量学与测量工程] P753[天文地球—测绘科学与技术]