1971-2000年营口地区大风特征及其变化分析

Characters of High Wind Days and Its Change in Yingkou Prefecture from 1971 to 2000

对1971—2000年营口地区各月大风及大风日数等要素资料的分析表明:1971—2000年营口地区各月最大风速≥6级和≥8级的日数表现为春季>冬季>秋季>夏季,≥6级和≥8级的年大风日数均呈递减趋势,变化速率分别为-27.4d/10a和-6.7d/10a;1981—2000年营口地区最大风速≥6级和≥8级的年大风日数变化速率分别为-13.1d/10a和-6.1d/10a,反映出1971—2000年大风日数递减趋势较1981—2000年显著,春夏季(3—6月)递减趋势尤为显著。气温日较差减小所导致的局地环流减弱可能是营口地区大风日数减少的一个原因。

The analyses of high wind days in Yingkou Prefecture from 1971 to 2000 indicate that days of wind speed above 6 and 8 categories in one year reduced successively from spring, winter, autumn to summer. Annual days of wind speed above 6 and 8 categories in the recent 30 years （1971 2000） reduced at a linear change rate of 27.4 d/10a and 6.7 d/10a, but in the recent 20 years （1981-2000）, the annual high wind days reduced at a linear trend of 13.1 d/10a and 6.1 d/10a, respectively, suggesting that the reducing trends of high wind days in the recent 30 years are more significant than those in the recent 20 years; and the reducing trends in spring and early summer （March to June） are more remarkable than those in autumn and winter. The weakening of local general circulation associated with the reduction in diurnal range might be one of the reasons for the decline in high wind days in Yingkou Prefecture