Remote sensing of diffuse attenuation coefficient of photosynthetically active radiation in Lake Taihu using MERIS data
Remote sensing of diffuse attenuation coefficient of photosynthetically active radiation in Lake Taihu using MERIS data
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利用MERIS数据遥感太湖光合有效辐射漫衰减系数
DOI：
10.1016/j.rse.2013.09.013
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发表时间：
2014-01-01
影响因子：
13.5
通讯作者：
Qin, Boqiang
中科院分区：
文献类型：
--
作者：
Shi, Kun;Zhang, Yunlin;Qin, Boqiang
特别是对于一个浅水和极度浑浊的湖泊，水体中的光的可用性可以确定透光层，以及藻类物种的水平和垂直分布。光衰减传统上被量化为光合有效辐射的漫射衰减系数（Kd（PAR））。太湖是我国重要的城市饮用水水源地，其K-d（PAR）的卫星观测数据可以提供高时空分辨率的全球覆盖，这些数据可以帮助我们更好地了解太湖的物理、化学和生物过程。K-d（PAR）与总悬浮物（TSM）浓度呈显著正相关。K-d（PAR）与TSM的决定系数（R-2 = 0.91）显著高于K-d（PAR）与叶绿素a浓度（Chl-a）的决定系数（R-2 = 0.11）和K-d（PAR）与有色溶解性有机物（CDOM）的决定系数（R-2 = 0.01）。利用中分辨率成像光谱仪（MERIS）遥感影像的10波段大气层顶（TOA）辐射数据，建立了太湖K-d（PAR）的反演模型，并与实测K-d（PAR）进行了相关分析。（R-2 = 0.74，p < 0.005，N = 48）。与此相反，MERIS图像数据的大气校正的反射率没有强烈的相关性，在原地的K-d（PAR）。利用2003 - 2010年太湖MERIS数据，研究了太湖K-d（PAR）的季节和空间分布特征。结果表明，太湖的K-d（PAR）值具有明显的季节性、空间性和风力驱动性。K-d（PAR）值在夏季最高，冬季最低。夏季K-d（PAR）的增加主要是由于浮游植物的大量繁殖和沉积物的再悬浮。在空间上，太湖南部和湖心的K-d（PAR）值较高，东太湖的K-d（PAR）值较低。结果表明，太湖K-d（PAR）与风速之间存在显著的正相关关系，表明风速在太湖K-d（PAR）变化中起着重要作用。(C)2013 Elsevier Inc. All rights reserved.
Especially for a shallow and extremely turbid lake, light availability in the water column can determine the euphotic zone, and the horizontal and vertical distribution of algae species. Light attenuation is traditionally quantified as the diffuse attenuation coefficient of the photosynthetically available radiation (K-d(PAR)). Global coverage of K-d(PAR) at high spatial and temporal resolution can be provided by satellite measurements, and these data can be used to improve our understanding of the physical, chemical and biological processes in Lake Taihu, a large shallow lake in China, of considerable importance as a source of drinking water for several large cities.The primary dominated contributor to K-d(PAR) was determined firstly using linear regression. There was a significant positive correlation between K-d(PAR) and concentrations of total suspended matter (TSM). The determination coefficient between K-d(PAR) and TSM (R-2 = 0.91) was significantly higher than that between K-d(PAR) and chlorophyll-a concentrations (Chl-a) (R-2 = 0.11), and between K-d(PAR) and absorption of chromophoric dissolved organic matter (CDOM) (R-2 = 0.01). Our results therefore could demonstrate that TSM usually plays a dominant role in the attenuation of light in Lake Taihu.A retrieval model of K-d(PAR) values for Lake Taihu was subsequently developed using top-of-atmosphere (TOA) radiance of Medium Resolution Imaging Spectrometer (MERIS) image data at band 10, which was strongly correlated with in situ K-d(PAR) (R-2 = 0.74, p < 0.005, N = 48). In contrast, the atmospheric corrected reflectance of MERIS image data was not strongly correlated with in situ K-d(PAR). Thus, atmospheric correction was not a prerequisite for estimations of K(PAR) in this highly turbid and hyper-eutrophic lake, and a simple empirical model of the K-d(PAR) estimation for Lake Taihu was effective.With the simple model, the seasonal and spatial distributions of K-d(PAR) in Lake Taihu were studied using the MERIS measurements from 2003 to 2010. Our results show distinct seasonal, spatial, and wind driven, K-d(PAR) values in Lake Taihu. The highest and the lowest K-d(PAR) values were found in summer and in winter, respectively. The increase of K-d(PAR) in summer can be attributed to the phytoplankton blooms, and wind-driven sediment resuspension. Spatially, the K-d(PAR) values were high in the southern part and the lake center, and low K-d(PAR) in East Lake Taihu. Based on the MERIS derived K-d(PAR) values, a significant correlation was found between K(PAR) and wind speeds, suggesting a critical role of wind speeds in the K-d(PAR) variations in Lake Taihu. (C) 2013 Elsevier Inc. All rights reserved.