关键词: 长江口, 风速, 风向, 风频率, 季节性变化

Abstract: The wind plays an important role in circulation, mixing, saltwater intrusion and sediment transport in the Changjiang estuary. Based on the observed wind speed and direction by the weather station at the Chongming eastern beach from December 2007 to February 2014，the wind rose diagrams and seasonal wind variations are presented and analyzed. From January to December, the mean wind speeds in each month are 4.2, 4.6, 4.9, 4.9, 4.7, 4.4, 4.9, 4.9, 4.5, 4.0, 4.1 and 4.3 m/s, mean wind directions in each month are N, NE, NE, SE, SE, SE, S, SE, NE, NE, N and N, respectively. Wind direction, frequency and averaged wind speed of the wind with the first, second wind direction frequency, the maximum average wind speed direction, strong wind direction domain and strong wind speed domain in each month are presented statistically. In overall, the wind at the Chongming eastern shoal has the feature of subtropical zone monsoon, prevailing southeasterly wind in spring and summer, and northerly wind in autumn and winter. The strong wind has an obvious seasonal variation, its frequencies in March, April and July, August are distinct higher than in other months. The strong wind frequencies in July and August is higher than in March and April, reaches to 0.8% and 1.52% with mean wind speed of 11.5 and 12.4 m/s. The wind at the Changjiang mouth is the basic dynamic factor in the study of dynamics process and material transport there.