Monitoring and predicting eutrophication of Sri Lankan inland waters using ASTER satellite data
Monitoring and predicting eutrophication of Sri Lankan inland waters using ASTER satellite data
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DOI：
10.1117/12.2067127
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发表时间：
2014-10
影响因子：
5.6
通讯作者：
D. Dahanayaka;M. Wijeyaratne;H. Tonooka;A. Minato;S. Ozawa;B. Perera
中科院分区：
文献类型：
--
作者：
D. Dahanayaka;M. Wijeyaratne;H. Tonooka;A. Minato;S. Ozawa;B. Perera
这项研究的重点是确定过去的变化和预测未来的趋势，在富营养化的博尔戈达北湖，斯里兰卡使用原位叶绿素a（Chl-a）测量和高级星载热发射和反射辐射计（ASTER）卫星数据。该湖位于一个混合土地使用区，有工业、一些农业用地、中等收入和高收入住房、旅游酒店和低收入住房。从2013年3月至10月，每月一次在ASTER立交桥旁采集5个采样点的水样，采用标准实验室方法测定每个样品的Chl-a、硝酸盐和磷酸盐含量。在2000-2013年期间，在湖上的无云ASTER场景获得叶绿素a估计和趋势分析。利用FLAASH软件对所有ASTER图像进行大气校正，并利用大气校正后的同一日期的3个ASTER VNIR波段比对现场叶绿素a数据进行回归。利用相关性最高的波段比与叶绿素a含量的回归方程，即绿色/红色波段比，开发了生成15 m分辨率叶绿素a分布图的算法。基于ASTER的叶绿素a分布图显示，该湖泊的富营养化程度在2008-2011年间逐渐增加。结果还表明，2013年全年，若干区域的富营养化程度很高，特别是在积水区和淡水出口附近。实地观察表明，这个湖正在接受来自工厂的各种排放物。无计划的城市化和附近工业废物管理的适当设施不足，导致水体富营养化。如果目前的废物处理和无计划的城市化趋势继续下去，将在未来造成巨大的环境问题。本研究的结果表明，从卫星遥感信息可以发挥有益的作用，在时间序列叶绿素a分布图的发展。这些信息对于该地区未来的预测、开发和管理以及保护该水体都很重要。
This study focused on determining the past changes and predicting the future trends in eutrophication of the Bolgoda North lake, Sri Lanka using in situ Chlorophyll-a (Chl-a) measurements and Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER) satellite data. This Lake is located in a mixed land use area with industries, some agricultural lands, middle income and high income housing, tourist hotels and low income housing. From March to October 2013, water samples from five sampling sites were collected once a month parallel to ASTER overpass and Chl-a, nitrate and phosphate contents of each sample were measured using standard laboratory methods. Cloud-free ASTER scenes over the lake during the 2000-2013 periods were acquired for Chl-a estimation and trend analysis. All ASTER images were atmospherically corrected using FLAASH software and in-situ Chl-a data were regressed with atmospherically corrected three ASTER VNIR band ratios of the same date. The regression equation of the band ratio and Chl-a content with the highest correlation, which was the green/red band ratio was used to develop algorithm for generation of 15-m resolution Chl-a distribution maps. According to the ASTER based Chl-a distribution maps it was evident that eutrophication of this lake has gradually increased from 2008-2011. Results also indicated that there had been significantly high eutrophic conditions throughout the year 2013 in several regions, especially in water stagnant areas and adjacent to freshwater outlets. Field observations showed that this lake is receiving various discharges from factories. Unplanned urbanization and inadequacy of proper facilities in the nearby industries for waste management have resulted in the eutrophication of the water body. If the present trends of waste disposal and unplanned urbanization continue, enormous environmental problems would be resulted in future. Results of the present study showed that information from satellite remote sensing can play a useful role in the development of time series Chl-a distribution maps. Such information is important for the future predictions, development and management of this area as well as in the conservation of this water body.