应用谱分析方法分析预报南沙海区冬季大风

Nansha Winter Gale Analysis and Prediction with Spectral Analysis Method

利用 ( 1989 年 11 月—1999 年 3 月) 冬季北半球 500 hPa 候平均高度资料，分析了南沙海区冬季大风（简称为南沙冬季大风）与北半球中、高纬西风带中的超长波、长波活动的关系。结果表明：中、高纬强冷空气爆发南下是造成南沙冬季大风的最主要原因；当中、高纬的角动量输送达到一定数值后，伴随南沙海区会出现一次大风过程；在南沙冬季大风出现前期，偏高纬度的角动量有一次同步向北输送过程，使中、高纬西风增强；结果还表明：纬向扰动动能大多集中在超长波段内，经向扰动动能随纬度的不同主要集中在 2～6 波波段内。文中在这一基础上分析得出南沙冬季大风的预报指标。

:In this paper, 500 hPa climatological mean altitude data in Northern Hemisphere in winter from 1989 to 1999 are used to analyze the relationship between winter gale in Nansha sea and wave undulation of ultra-long wave and long wave in westerly belt in high latitude of Northern Hemisphere, and it is found that the main cause of the winter gale in Nansha sea is the burst of severe cold air in middle latitude and high latitude and its southern movement. When the angular momentum transportation in middle latitude and high latitude reaches a certain value, the gale will occur in Nansha sea. And, with the spectral analysis method, the winter gale is analyzed and predicted in this paper.