Abstract：
Lake surface water temperature (LSWT) plays a crucial role in assessing the health of aquatic ecosystems. Variations in LSWT can significantly impact the physical, chemical, and biological processes within lakes. This study investigates the long-term changes in surface water temperature of the Dongting Lake, China. The LSWT is retrieved using Landsat thermal infrared imageries from 1988 to 2022 and validated with in situ observations, and the change characteristics of LSWT and near-surface air temperature (NSAT) as well as the spatial distribution characteristics of LSWT are analyzed. Additionally, the contribution rates of different meteorological factors to LSWT are quantified. The results show that the accuracy assessment of satellite-derived temperatures indicates a Nash-Sutcliffe efficiency coefficient (NSE) of 0.961, suggesting an accurate retrieval of water temperature. From 1988 to 2022, both the annual average LSWT and NSAT of Dongting Lake exhibit an increasing trend, with similar rates of warming. They both undergo a mutation in 1997 and have the main periods on the 11-year and 4-year time scales. The changes in NSAT emerge as one of the important factors contributing to variations in LSWT. Among the multiple meteorological factors, NSAT exhibits a significant correlation with LSWT (R = 0.822, α < 0.01). Furthermore, NSAT accounts for the highest contribution rate to LSWT, amounting to 67.5%. The distribution of LSWT within Dongting Lake exhibits spatial variations, with higher LSWT observed on the west part compared to the east part during summer, while lower LSWT occurs on the west part during winter. The findings of this study can provide a scientific understanding for the long-term thermal regimes of lakes and help advance sustainable lake management.
摘要：
湖泊地表水温度（LSWT）在评估水生生态系统的健康中起着至关重要的作用。LSWT的变化会显著影响身体，化学,和湖泊内的生物过程。这项研究调查了洞庭湖地表水温度的长期变化，中国。从1988年到2022年，使用Landsat热红外图像检索了LSWT，并通过原位观测进行了验证。分析了LSWT和近地表气温(NSAT)的变化特征以及LSWT的空间分布特征。此外,量化了不同气象因素对LSWT的贡献率。结果表明，对卫星得出的温度的准确性评估表明Nash-Sutcliffe效率系数（NSE）为0.961，表明可以准确检索水温。从1988年到2022年，洞庭湖的年平均LSWT和NSAT均呈增长趋势，类似的升温速度。它们都在1997年发生突变，并且在11年和4年的时间尺度上具有主要时期。NSAT的变化是导致LSWT变化的重要因素之一。在众多气象因素中,NSAT与LSWT呈显著相关(R=0.822,α<0.01)。此外，NSAT对LSWT的贡献率最高，达67.5%。洞庭湖内LSWT的分布表现出空间变化，夏季，与东部相比，西部的LSWT更高，而冬季西部LSWT较低。这项研究的结果可以为湖泊的长期热力状况提供科学的理解，并有助于推进可持续的湖泊管理。
