气候变暖趋势下龙羊峡水库水温结构模拟研究

Simulation Study on Water Temperature Structure of Longyangxia Reservoir Under Climate Warming Trend

在气候变暖与高海拔水库建设运行的共同作用下,区域性气候环境对河道水温的年内变化作用明显。以黄河上游多年调节水库龙羊峡水库为研究对象,在入库水温与气温相关性分析的基础上,采取原型观测方法研究坝前水温变化与天然河道水温和气温变化的相关性,通过建立三维水温模型对库区水温结构的季节性变化进行模拟。结果表明:坝前水温的年内变化滞后于气温的,龙羊峡水库的兴建改变了库区水体的热量分配,6—9月水库表层水体吸收了大量热量,和底层水体之间存在较大的温度梯度并形成温度分层,10月至次年3月上下层水体水温近乎等温状态;龙羊峡水库地处高寒地区,在蓄水期形成水温分层时,除在气温最高的月份形成较大斜温层梯度外,没有形成明显温跃层。

Under the joint action of climate warming and the construction and operation of high altitude reservoir, the appearance of regional climate environment has an obvious effect on the annual variation of river water temperature. Taking the results of multi-year regulating storage reservoirs in the Yellow River upstream of the reservoir as the research object, through the analysis of the correlation between the storage temperature and temperature and on the basis of prototype observation methods, it studied the water temperature changes in the front of the dam and the correlation of natural river water temperature and the temperature change, through the establishment of 3-D temperature models of seasonal changes on the structure of the reservoir water temperature simulation. The results show that the annual change of water temperature in front of the dam is lagging behind the change of air temperature. The construction of Longyangxia Reservoir changes the heat distribution of the river, the surface water body of the reservoir absorbs a lot of heat from June to September, and there is a large temperature gradient between the bottom water body and the surface water body, the water temperature of the upper and lower water bodies is nearly isothermal from October to March of the following year. Because the Longyangxia Reservoir area is in an alpine and cold region, the surface water of the reservoir absorbs less heat during the storage period when the water temperature is stratified and there is no obvious thermocline except for the formation of a large thermocline gradient in the months with the highest temperature.