摘要
在Webster等人工作的基础上，以三维湖流为背景，考虑了波浪及藻类自身浮力的影响，建立了一个太湖梅梁湾三维藻类迁移模型，以研究在不同风场作用下藻类在湖泊中的迁移过程．模拟结果表明，不同风场对于藻类在湖泊中的水平及垂直分布影响很大，并且存在着一个临界风速，其范围在2－3m／s之间，当风速小于临界风速时，水面可以近似看作水动力光滑，没有波浪产生，在水表面藻类顺着风向迅速向迎风岸边漂移，形成藻类大量堆积．但当风速超过临界风速时，将产生波浪作用，波浪、风扰动及平均环流的共同作用使得藻类在水体中上下混合，分布比较均匀．在太湖水华暴发季节，藻类的运动符合上述模拟结果．
A three-dimensional model in which the effects of buoyance and wave are considered is developed to demonstrate how the tendency of algae to move, coupled with wind-induced circulation, leads to horizontal and vertical heterogeneity in algae concentration in Taihu Lake. Results show that the distribution of algae will be different depending on whether the windspeed is higher or lower than the critical windspeed. If the windspeed is lower than the critical one,algae may migrate toward the downwind end of the lake and accumulate there. The floating algae are expected to remain on the surface. But above the critical windspeed, water surface becomes rough and waves take place. In that case, interactions between wind-generated turbulence. mean currents and waves cause algae to leave away from the water surface, so surface accumulation of algae do not occur again. In summer, the algae of Taihu Lake migrate with southeast wind toward the northwest region of the lake and then form blooming there for low windspeed; but when the windspeed above the critical value, the wind-generated waves may impress the accumulation of algae and make algae distribute more uniformly in the lake. This result is verified by the observed data of Taihu Lake.
出处
《湖泊科学》
EI
CAS
CSCD
1997年第2期152-158,共7页
Journal of Lake Sciences
基金
国家自然科学基金!39500027
关键词
藻类迁移
水华暴发
波浪作用
太湖
动力学
风场
the migration of algae, wind-generated waves,critical windspeed,Taihu Lake
