In September 2008, a meteorology-hydrology-water quality simultaneous observation was conducted to study the influences of prior wind field on hydrodynamic characteristics and cyanobacterial bloom in northern bays ( Meiliang Bay and Conghu Bay) of Lake Taihu. The results showed that exposed to prior wind field, the surface, middle and bottom water layers flowed out of the bays. There was no compensation current in the two bays. Surface current field was sensitive to real wind field, but middle and bottom current fields lagged behind the wind changing. Influenced by southeast wind, a clockwise circulating current could be rapidly formed in the surface water layer of Meiliang Bay. In Gonghu Bay. The flow direction of surface current field did not change under the action of Westerlies, but its magnitude decreased obviously so that the current velocity increased with the water depth. The observation proves that hydrodynamic is very important for the stratification of chlorophyll-a concentration and drift of cyanobacterial bloom in northern bays of Lake Taihu. Cyanobacteria tended to accumulate and form bloom on water surface in low-hydrody-namic area. Under the condition of high-intensity disturbance, cyanobacteria mixed along the water depth. This can greatly decreased the risk of cyanobacterial bloom. Comparing with the influence of hydrodynamic, that of nutrients on the distribution of chlorophyll-a concentration was less important.%为明确前期风场对太湖北部湖湾水动力及蓝藻水华分布的影响,对2008年9月梅粱湾及贡湖湾水文、水质及气象开展了同步观测,结果表明:受前期东北风影响,梅梁湾及贡湖湾表层、中层及底层湖流流向均顺风向自湾内流向湾外,两个湖湾均不存在补偿流.表层湖流对风场变化响应敏感,而中场及底层流场对风场变化响应存在显著滞时.在偏南风作用下,梅梁湾表层湖流能快速形成顺时针环流.在偏西风作用下,贡湖湾表层湖流流向虽未发生偏转,但是湖流流速显著减小并导致流速沿水体垂向呈递增分布.观测期间水动力强度对太湖北部湖区叶绿素a浓度垂向分层及蓝藻水华水平漂移均具有重要影响.在水动力滞缓水域,蓝藻水华易在水表发生漂移堆积.在水动力强度较大水域,强烈的垂向混合作用能使蓝藻沿水深方向混合均匀,降低水华暴发风险.相对于水动力条件,营养盐对叶绿素a浓度空间分布的影响较弱.
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