赤潮发生规律及气象条件

Regularities and Meteorological Conditions of Red Tide Emergence

根据国家海洋局1990～2003年《中国海洋灾害公报》中我国沿海赤潮的相关资料，分析了我国赤潮的时空分布特点，我国近几年赤潮发生增长较快，几乎全年都有发生，主要集中在5～9月，沿海各省都有赤潮发生，浙江省、长江口一带最盛。对浙江舟山沿海发生赤潮时的气象要素研究表明，其主要特点是湿度大、气压低、日照时间长、风向偏东居多。赤潮发生时的3个天气形势特征：高空西北偏西气流；地面一般为均压场，气压低；在我国东部沿海地区近地层有很大的东西向温度梯度，并分析了这样的形势适合赤潮发生的原因。

The characteristics of the spatial and temporal distribution of red tides in China along the China coast are analyzed based on Oceanic Calamity Communique in China. The results show that red tides increase very fast in recent years, and they occurs almost at any time of a year in every coastal province and more frequently from May to September, most likely in Zhejiang Province around the estuary of the Yangtze River. The meteorological elements at the Zhoushan Station during the red tides are analyzed. The main characteristics include high humidity, low atmospheric pressure, long sunshine duration, and east winds. The weather patterns during red tides are summed up from the weather charts of the same time： there exists northwest wind at the upper level and low uniformed surface pressure; at the near surface layer, there are massive high temperature gradient areas along the east coastal area of China. The relation of red tides and weather patterns are discussed.