Evaluation of the effects of climate change on lake water environment as regional freshwater resources

在观测结果中，从1990年到2010年，池田湖底层处于缺氧状态长达21年。2011年2月中旬，1月至2月的平均气温下降了8°C，这是自1987年以来的最低水平，由于地表水冷却发生了垂直混合，因此得到了统一的垂直溶解氧剖面(4.5毫克/L)。在12月至2月期间，这一逆转持续了约50天。利用垂直一维数值模式研究了变暖趋势下的湖泊水温和溶解氧动态。数值分析表明，1984、1986和2011年的湖泊稳定性指数为负值，与倾覆的年份相对应。

In the observed results, the bottom layer of Lake Ikeda was under anoxic condition for 21 years from 1990 to 2010. In the middle of February 2011, when the mean air temperature from January to February decreased by 8°C, the lowest since 1987, vertical mixing due to surface water cooling occurred and consequently a uniform vertical dissolved oxygen (4.5 mg/L) profile was attained. The overturn was achieved for about 50 days during December to February. The lake water temperature and dissolved oxygen dynamics under the warming trends were investigated by the vertical one-dimensional numerical model. The numerical analysis reveals that 1984, 1986 and 2011, in which the values of lake stability index were negative, correspond to the years of the overturn.