• 关键词：太湖  真光层深度  光谱分布  悬浮物浓度  岭回归分析

• 基金项目：国家自然科学基金资助项目(No.41371222);国家重大科技专项(No.2012ZX07101-010)

• 赵巧华
• 南京信息工程大学, 南京 210044

• 王玲
• 南京信息工程大学, 南京 210044

• 杭蓉蓉
• 南京信息工程大学, 南京 210044

• 摘要：基于2010年5月份全湖28个站点分层测量的水体下行辐照度以及各光学介质(有机悬浮物LOI、无机悬浮物ISS、叶绿素a Chl-a)浓度的实测数据,本文运用岭回归分析法,分析了不同湖区5月份真光层深度谱的分布特征及其影响因素.结果表明整个有效光合辐射范围内,3种因素对真光层深度的贡献均为负,ISS浓度是真光层深度的主要贡献因子,贡献率达0.48~0.62;其次为LOI浓度,贡献率为0.34~0.45;Chl-a浓度的贡献最小,贡献率为0.05~0.09.675 nm处,ISS的贡献具有谷值,Chl-a与LOI的贡献却为峰值;520~650 nm处Chl-a贡献值保持低值.此外,按各采样点的真光层深度谱分布的线型向量空间余弦相似度(cosine)进行分步聚类(Ascending Hierarchical),将全湖分为二类,梅梁湾、竺山湾、贡湖湾以及胥口湾以北区域为第一类,其余区域为第二类.结合全湖所有采样点的各介质浓度数据,发现第一类采样点LOI与Chl-a的相对浓度大于第二类,此两类介质浓度凸显了650 nm、675 nm处真光层深度谱分布曲线的波谷特征.

• Abstract：Based on the measured profiles of the underwater down welling irradiance and the concentration of the optically active substances(inorganic suspended solids、organic suspended solids、chlorophyll a)from 28 sampling sites in Lake TaiHu in May 2010, the spectral distribution characteristics of euphotic depth were analyzed by using clustering method, and quantitative effect of optical media on spectral shape of euphotic depth was quantified by ridge regression. The results show that:In the waveband of photosynthetically active radiation, the contribution of the three optical media were negative, and inorganic suspended solids were the dominant factor, with a contribution rate between 0.48 and 0.62; followed by organic suspended solids and chlorophyll a, with the rates of 0.34~0.45 and 0.05~0.09, respectively. The contribution valley of inorganic suspended solids was at about 675 nm, while the contribution peak of organic suspended solids and chlorophyll a were both at same wavelength; the contribution of chlorophyll was insignificant from 520 nm to 650 nm. In addition, the spectral distribution of euphotic depth is clustered with Cosine, which were divided into 2 kinds according to the sampling spatial sites. The bays, including MeiLiang, ZhuShan, GongHu and XuKou, were in one kind, and the rest areas belonged to the next. Combining with concentration of the three substances, the relative concentration of organic suspended solids and chlorophyll a of the first category were higher than those of the second, which confirmed the valley of spectral distribution at 650 nm and 675 nm.

• Key words：Lake TaiHu  euphotic depth  spectral distribution  concentration of suspended solids  ridge regression

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