水库坝前水温结构日变化规律研究

Research on Daily Variation of Water Temperature Structure in Front of Dam

水库水温结构受来流水温和气象要素的影响,在年内呈现周期性变化,但对其日内变化规律的认识较为缺乏。以龙滩水库为研究对象,于2011年11月—2012年9月分6期对龙滩水库坝前水温进行了原型观测。资料分析结果表明:龙滩水库库区水温除1月外,其余各月均存在分层现象,在7月和9月出现了双温跃层;表层水温年内变化较大,库底水温全年较为稳定;气象要素对坝前水温影响深度与季节有关,夏季影响深度最大;气温越高水温最大值出现的时间越早;水温结构日变化的影响因素主要是气温和太阳辐射,此外坝前水温结构日内变化明显的范围仅为库表20 m,表层水温的日内变化几乎不对电站发电取水水温构成影响。

Based on Longtan reservoir, a prototype observation in front of the dam,which was divided into six stages,was performed from November 2011 to September 2012. The data analysis showed that water temperature stratification was relatively stable during the observation period except January, and double thermocline was observed in July and September. The surface temperature had a big variation, while the bottom temperature was relatively stable throughout the year. The influence scope of meteorological elements on： the water temperature in front of the dam was related to the season. In summer the reservoir water was impacted by the meteorological elements deeper than the others. Air temperature and solar radiation were the main factors affecting the diurnal variations of the structure of water temperature. In addition, the daily significantly changed area of water temperature structure was only within 20 m of the surface, which indicted that the diurnal change of surface water temperature hardly affected the temperature of discharge water.