湛江东海岛二月海陆风环流特征研究

利用2011年2月湛江东海岛风廓线雷达资料,系统分析了湛江东海岛2月平均风场特征及海陆风特征,结果表明:2月湛江东海岛150 m高度处以东偏北出现频率最大,在E、ENE和NE三个方位的风向出现频率之和为66.6%,偏西七个方位的风向出现频率之和仅为1%。以SSW方位为界,偏东风与偏西风的出现频率差异明显。各整点的月平均风速1:00—15:00变化较小,均在1 m/s左右波动;15:00—20:00风速及风速波动都较大,最大值出现在16:00时,为2.1 m/s。2011年2月中只有2日与14日两日符合海陆风日条件,两日共同海风时段为13:00—20:00,持续7 h;陆风时段为2:00—7:00,持续5 h。海风平均风速为2.1 m/s,陆风平均风速为0.8 m/s,海风平均风速明显大于陆风风速。海风与陆风环流垂直高度相差甚小,约1.2 km,风速随高度变化趋势均为先增后减;海风最大风速出现在750 m高度处,陆风出现在500 m高度处,500～750 m高度区间海风环流强度明显强于陆风环流。2 km之上为均匀一致的系统性西风环流。

Analyses on characteristics of sea-land breeze over Donghai island of Zhanjiang in February of 2011

The average wind characteristics and sea-land breeze characteristics are analyzed by using the data of wind profiler during February 2011 on Donghai island of Zhanjiang. The results show that: the prevailing wind direction is northeasterly on Donghai island during February 2011 at an altitude of 150 m and the total frequency of occurrences of three directions E, ENE, NE is 66.6%, in contrast, the total frequency of occurrences of westerly is only 1%. There is an obvious difference of occurrence frequency between westerly winds and easterly winds. The hourly changes of average monthly wind speed is restricted to small range about 1 m/s from 1:00 to 15:00; and fluctuation becomes larger during 15:00 to 20:00, the maximal speed of 2.1 m/s appears at 16:00. In February, only two days meet the conditions of sea-land breeze. In sea-land breeze day, the common duration of sea breeze is from 13:00 to 20:00, lasting 7 h, and land breeze's common duration is from 2:00 to 7:00, lasting 5 h. The mean speed of land breeze is 0.8 m/s, which are smaller than 2.1 m/s of sea breeze. The vertical height of land breeze is about 1 200 m during the sea-land breeze day, which differs slightly from sea breeze. The wind speeds of both sea breeze and land breeze have the similar trends of increasing first and then decreasing with increasing altitude. The maximal wind speed of sea breeze appears at 750 m, and that of land breeze appears at 500 m. The sea breeze circulation is much stronger than land breeze in the region of 500 to 750 m height. The wind direction basically remains unchanged above 2 km and that is the large-scale uniform systematic west wind circulation.