中文摘要：

湖泊热力分层及热力循环深刻影响深水湖泊生态系统。随着全球气候变暖,湖泊热力过程会发生显著变化。作为深水水库型湖泊,千岛湖的热力过程与水环境的变化紧密相连,为了分析千岛湖水体水温、湖泊热力分层参数（温跃层深度、厚度和强度）的分布,探讨温跃层深度与水温、水体透明度以及水深之间的关系,本文根据2014年7月份与2015年5月份对千岛湖全湖60个采样点的水体理化指标的垂向分布调查数据,计算得到千岛湖热力分层参数,进而分析其时空分布特征及主要影响因素。结果表明,千岛湖水体水温垂直分布呈现正温分布,春夏季全湖范围内均存在不同程度的温度分层现象,温跃层深度、厚度和强度均从上游河口向下游敞水区逐步增大,这种空间变化的趋势在7月份比5月份更显著。水温、透明度和水深是影响温跃层深度的主要因素。夏季湖泊热力分层稳定期温跃层深度与表层水温（0—2m）存在显著负相关关系,与透明度和水深存在正相关关系。

英文摘要：

Thermal stratification and circulation in a lake affected the deep lake water ecosystem significantly. Lake thermal processes change obviously in the realm of the global warming. We conducted an investigation in 60 sites from July 2014 to May 2015 in Qiandao Lake（or Xin＇anjiang Reservoir build in 1959. Qiandao means thousand isles in Chinese. In maximum, area 580km~2, volume 178.4×10~8 m~3, depth 108m（average depth 31m））, Zhejiang, East China, to analyze the distribution of water temperature and thermal stratification. Relationships of water temperature, transparency, and depth to the thermocline depth were regressed. Thermal stratification parameters based on the in-situ lake-wise physical and chemical data. Results show that thermal stratification appeared in spring and summer, to which water temperature was the main controller, followed by transparency and depth. The depth, thickness, and strength of thermocline increased from upstream to downstream, especially in July than in May. In the summer, the thermal stratification was stable, and the thermocline depth showed significantly negative relation with the surface temperature, and positive with transparency and depth.