近年来,位于云南省境内的洱海湖区蓝藻水华现象频发引起了人们的关注。叶绿素a是水体初级生产力的重要指标,可以有效反映浮游植物生物量状况及其变化趋势。本文选取了蓝藻水华易爆发期(2009年5月~11月)洱海湖区Landsat TM/ETM+数据,在对图像进行了辐射定标、大气校正、条带修复等预处理的基础上,运用41.57 × (TM3 + TM4) − 0.697波段组合模型对其进行叶绿素a浓度反演,反演结果表明,洱海湖区叶绿素a含量逐渐升高,在10月份达到了峰值,11月开始下降。各时相叶绿素a浓度反演结果与实际采样分析结果基本一致,验证了利用Landsat TM/ETM+数据进行洱海湖区叶绿素a浓度动态监测的有效性。该方法具有周期短、信息丰富、现势性强、成本低等优势,值得进一步推广。 In recent years, algal bloom occurring in Erhai frequently attracts wide attention. The chlorophyll-a concentration, which can effectively reflect the status of phytoplankton biomass and its change trend, is an important parameter for evaluating primary productivity of the water. Using the Landsat TM/ETM+ remote sensing images when cyanobacteria bloom erupted (from May to November in 2009), after pre- processing like radiometric calibration, atmospheric correction and destriping on the images, the chlo-rophyll-a concentration was quantitatively inversed by the band combination of 41.57*(TM3 + TM4) − 0.697. The results showed that chlorophyll-a concentration in Erhai Lake increased gradually and reached the highest value in October, then decreased in November. Chlorophyll-a concentrations in each phase inversion result are consistent with the actual results of sampling and analysis that demonstrates the effectiveness of the use of Landsat TM/ETM+ data on dynamic monitoring chlorophyll-a concentration of Erhai Lake. This method is worthy of further promotion with short period, rich information, high actuality and low cost.
研究选取位于云南大理的洱海作为研究区,是云南省第二大淡水湖。地理坐标位于N25˚36'~25˚58',E100˚06'~100˚18'之间。总径流面积2565 km2,湖泊面积约251 km2,蓄水量30亿m3,平均水深约11.5 m,最深为20 m [4] 。选取2009年5~6和8~11月共六景Landsat TM/ETM+遥感数据,均来源于地理空间数据云(Geospatial Data Cloud)。
李泠潞,李嘉璇,成 功. 基于Landsat数据的洱海蓝藻动态变化监测 The Dynamic Monitoring of Erhai Cyanobacteria Based on Landsat Data[J]. 水资源研究, 2016, 05(02): 167-173. http://dx.doi.org/10.12677/JWRR.2016.52022
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