晋江水体真光层深度遥感反演

Retrieval of Euphotic Zone Depth of Jin River by Remote Sensing Technology

通过2008年3月在晋江下游泉州河段对水体固有光学特性和光学活性物质浓度的测定，计算得到晋江水体在光合有效辐射（PAR）波段内的漫射衰减系数Kd（PAR）和水面下反射率R（0^-）等表观光学特性．应用统计方法分析了PAR真光层深度的影响因素．结果表明，PAR真光层深度主要受悬浮物浓度的影响．基于生物光学特性，悬浮物浓度可从Landsat TM影像上获取，进而依据PAR真光层深度与悬浮物浓度之间的关系推算真光层深度．反演结果表明，晋江的真光层深度均值为2．43m，其变化范围为0．43—8．41m．该技术有别于以往研究采用SeaWiFS数据对真光层深度的反演，是一种适合于河流水体的真光层深度遥感反演方法．

Water samples were collected for obtaining Inherent Optical Properties （IOP＇s） and the concentration of the optically active substances in Jin River in March 2008. The diffuse attenuation coefficient in PAR--Kd （PAR） and the subsurface irradiance reflectance R （0^-） were computed using the observation result. And then, the potential factors, including the suspended solids （SS）, chlorophyll a （Chla） and chromomorphic dissolved organic matter （CDOM）, and how the factors influence the euphotic zone depth in PAR （Zeu） can be acquired by the empirical algorithms using statistics analysis. Results show that Zeu is governed by the concentration of SS, CDOM is less significant whereas the concentration of Chla is the last. The concentration of SS can be retrieved from Landsat TM image based on the bio-optical properties of water, therefore Zeu can be achieved depending on the relationship between Zeu and the concentration of SS. Landsat TM derived Zeu of Jin River showed distinctive spatial variability. The average of Zeu in Jin River is 2. 43 m, and the variable range is 0.43-8.41 m.