【摘要】 结合2015年9月镜泊湖30个有效采样点的实测叶绿素a质量浓度和同步Landsat 8 OLI数据,通过分析叶绿素a的光谱特征,在Landsat8OLI数据11个波段中,选择前7个波段(B1、B2、B3、B4、B5、B6、B7)单独或组合建立叶绿素a质量浓度反演模型。利用多元统计分析法分析发现,波段组合B5/B3、(B3+B4)/B5、B3/(B1+B5)模型精度较好,决定系数R2分别为0.754 1、0.774 3、0.739 6。作为对比,另外选取典型的水体指数建立叶绿素a质量浓度反演模型;其中归一化水体指数(NDWI)、改迚归一化水体指数(MNDWI)、增强型水体指数(EWI)模型较好,R2均大于0.7,分别为0.747 6、0.726 7、0.763 5。选取上述6种模型,利用剩余采样点迚行精度检验,结果预测值与实测值之间的R2为0.0711～0.8094,其中,NDWI模型反演R2值为0.7614,平均相对误差为13.0%,最大相对误差为22.4%,最小相对误差为1.4%;均方根误差为0.20μg/L。与波段组合模型相比,水体指数模型虽然精度没有较大的提高,但其模型摆脱了波段的随机组合,更适合用来作为镜泊湖叶绿素a常用的监测方法。通过NDWI模型对镜泊湖叶绿素a质量浓度的反演,发现镜泊湖叶绿素a质量浓度分布具有一定的空间差异性,大体趋势为靠近岸边的浅水区叶绿素a质量浓度高于湖心的深水区,有河流注入的来水区高于其他湖区。更多还原

【Abstract】 Combined the chlorophyll a concentrations of 30 sampling sites in Jinpo Lake collected in September of 2015 with the Landsat 8 OLI data,the spectral characteristics of chlorophyll a were analyzed.In 11 bands of Landsat 8 OLI data,the first seven bands(B1,B2,B3,B4,B5,B6,B7) were selected to construct the chlorophyll a concentration inversion model individually or in combination using multivariate statistical analysis method.The results showed that B5/B3,(B3+B4)/B5,and B3/(B1+B5) model showed better accuracy with R2 0.754 1,0.774 3 and 0.739 6 respectively.As a comparison,several typical water body index models were selected,in which the NDWI,MNDWI and EWI models had their R2 larger than 0.7,(0.747 6,0.726 7 and 0.763 5 respectively).Then we chose the six models for further regression analysis.The results of the 6 models showed that the R2 between predicted values and measured chlorophyll a were in the range 0.071 1-0.809 4.In the NDWI model,R2 was 0.761 4 with average relative error of 13%,the maximum relative error of 22.4%,the minimum relative error of 1.4%,and the root mean square error of 0.20 μg/L.Compared with the band combination model,the water body index model did not need the band random combination and was more suitable as a common method for monitoring water quality in lakes.The spatial distribution of chlorophyll a concentrations showed some space variability.The chlorophyll a concentrations in shallow water areas were higher than those in the central area,whereas the chlorophyll a concentrations in the inlet area were higher than those in other areas.更多还原