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利用光学遥感反演盐度,可以充分利用遥感数据的空间代表性,以及目前高分率遥感数据的高时空精度。本文利用MERIS(Medium Resolution Imaging Spectrometer)300 m数据,以干旱区的博斯腾湖(博湖)为例,探讨了光学遥感数据反演低盐湖泊水体盐度的可行性。结果显示:在开都河入流影响的博湖西南角,存在光学遥感反演盐度利用的黄色物质(CDOM)与盐度的反比关系,但相关性不高,而且在博湖区域不同时间、不同区域CDOM与盐度的关系都不同。博湖盐度低于3 g·L-1,而遥感数据计算盐度的精度约为1.1 psu,因而用光学遥感数据计算博湖盐度的误差太大。博湖本身CDOM与盐度关系的时空异质性以及相关性不高,目前光学遥感反演精度有限,因此,在博湖用光学遥感数据反演整个湖区的盐度有困难。用光学数据反演水体盐度要求盐度足够高,盐度和CDOM存在梯度,并满足CDOM扩散守恒,因此用光学遥感反演低盐湖泊水体盐度较为困难。
Using remote sensing to retrieve salinity can make full use of the spatial representation of remote sensing data and the high spatio-temporal accuracy of current high-resolution remote sensing data. In this paper, using the data of 300 m from the Medium Resolution Imaging Spectrometer (MERIS), taking the Bosten Lake (Bohu) in the arid area as an example, the feasibility of using the optical remote sensing data to retrieve the salinity in the low-salt lake waters was discussed. The results show that there is an inverse relationship between the CDOM and salinity of the optical remote sensing inversion salinity in the southwestern corner of Bohu Lake affected by the Kaidu River inflow, but the correlation is not high, and at different times in the Bohu Lake region, The relationship between CDOM and salinity varies from region to region. The salinity of Bohu is lower than 3 g · L-1, while the precision of calculating salinity by remote sensing data is about 1.1 psu. Therefore, the error of calculating the salinity of Bohu by using optical remote sensing data is too large. The temporal and spatial heterogeneity of the relationship between the CDOM and salinity in Lake Bo and its correlation is not high. At present, the retrieval accuracy of optical remote sensing is limited. Therefore, it is difficult to retrieve the salinity of the whole lake with optical remote sensing data. The inversion of water salinity by optical data requires that the salinity is high enough, the salinity and CDOM exist gradient, and the conservation of CDOM diffusion is conservative. Therefore, it is difficult to retrieve the salinity of low salinity water by optical remote sensing.