Optical attenuation characteristics of Lake Daye, Hubei Province based on remote sensing inversion of Landsat 8 OLI

Abstract

水体光学衰减特性直接影响湖泊的清澈程度和沉水植被的生存，利用遥感技术获取湖泊光学衰减分布特性能极大提高效率.基于2017—2019年的原位调查数据，利用Landsat 8 OLI影像开发了大冶湖水体光学衰减系数（K_d）的遥感反演模型，并分析大冶湖水体K_d的多年时空分布特性与驱动机制，以期为大冶湖流域的修复与管理提供参考.结果表明：波段比二次模型K_d=9.61（B1/B4）²-2.41（B1/B4）-6.40效果最好，精度达到R²=0.79，MAPE=23.9%，RMSE=0.89 m^-1.大冶湖水体K_d值的主要影响因素为悬浮物和浊度等，其次为有色溶解性有机物和叶绿素a.大冶湖K_d值分布在空间上由西向东逐渐递减，但局部也受到风速、陆源输入、人为活动和微生物活动等的影响，季节上平均以夏季最高、冬季最低.2013年以来大冶湖水体K_d值整体呈现下降趋势.;The optical attenuation characteristics of water directly affect the clarity of lake and the survival of submerged macrophytes. Using the way of remote sensing to obtain the optical attenuation distribution characteristics of lakes can greatly improve the efficiency. Lake Daye, located in Huangshi City, Hubei Province, is a typical shallow lake in the middle reaches of the Changjiang (Yangtze) River. Based on the in-situ survey data from 2017 to 2019, the remote sensing inversion model of Lake Daye water optical attenuation coefficient (K_d) is developed by using Landsat 8 OLI images, and the multi-year temporal and spatial distribution characteristics and driving mechanism of K_d in Lake Daye are analyzed, so as to provide reference for the restoration and management of Lake Daye basin. The results show that:the band ratio quadratic model was the best model (K_d=9.61 (B1/B4) ²-2.41 (B1/B4) -6.40), and its accuracy was R²=0.79, MAPE=23.9%, RMSE=0.89 m^-1. The main influencing factors of K_d of Lake Daye were suspended solids and turbidity, followed by chromophoric dissolved organic matter and chlorophyll-a. Moreover, the K_d value of Lake Daye decreased gradually from west to east in space, but it was also affected by wind speed, land-based input, human activities and microbial activities in some parts. The average of K_d is highest in summer and lowest in winter. Since 2013, the K_d value of Lake Daye has shown an overall downward trend.