基于高原盐湖光谱特性下的溶解氧反演应用与探讨

Application and exploration of dissolved oxygen inversion of plateau salt lakes based on spectral characteristics

因地理条件限制,盐湖高光谱反演研究目前尚少,文章以盐湖溶解氧的反演为例,探讨盐湖水质参数的反演思路与方法。通过对青海察尔汗盐湖水体高光谱数据的信息分析,在高光谱水质参数反演技术基础上利用盐湖水体的独特光谱信息,采用波段组合的方式确定了盐湖高光谱溶解氧反演模型。研究结果表明:①原始光谱曲线各个波段与溶解氧含量相关性不足0.3,基于盐湖水体的独特光谱信息下的波段组合数据与溶解氧含量的相关系数达到0.75以上;②建立的波段比值模型与实测值进行模型精度验证,发现溶解氧含量反演与实测结果基本一致;③盐湖水体较为稳定的特性使其在经历时间变化时水质参数含量不会发生较大变化,利用2019年11月份实测数据进行的精度验证也可说明以盐湖光谱特性建立的波段比值模型具有较高精度,并且能够有一定的模型长效性。因此,利用盐湖光谱特性建立高光谱反演模型可满足对该湖区进行溶解氧监测的精度需求,实现对其的大面积监测,也同时提出一种新的针对高原盐湖反演模型建立的思路,为后续高原湖泊的监测体系建立奠定基础。

The studies on the hyperspectral inversion of salt lakes are still scarce due to the limitations of geographical conditions at present.This study explores the inversion ideas and methods of the water quality parameters of salt lakes by taking the dissolved oxygen inversion of a salt lake as an example.Based on the analyses of the hyperspectral data of the Chaerhan Salt Lake in Qinghai Province and the hyperspectral inversion technology of water quality parameters,this study determined the hyperspectral inversion model of the dissolved oxygen in the salt lake by means of waveband combination using the unique spectral information of the water body of the lake.The results show that the correlation coefficient between various wavebands of the original spectrum curve and the dissolved oxygen content was less than 0.3,while that between the band combination data in the unique spectral information of the water body and the dissolved oxygen content was greater than 0.75.According to the precision verification of the finally established band ratio model using the measured value,the inversion result of the dissolved oxygen content was roughly consistent with the measured value.It is impossible for the water quality parameters to significantly change with time owing to the relatively stable nature of the water body of the salt lake.Therefore,the verification using the measured data of NovembeR^(2)019 can also indicate that the waveband ratio model established based on the spectral characteristics of the salt lake enjoys high precision for a long term.Therefore,the hyperspectral inversion model can meet the precision requirements for the large-area monitoring of the dissolved oxygen in the lake area.Meanwhile,this study also proposed a new idea for the establishment of the inversion model of plateau salt lakes,which lays a foundation for the establishment of the monitoring system of plateau lakes in the future.