乌鲁木齐市城区和郊区近地层风速廓线

Surface Layer Wind Speed Profiles in Center and Suburbs of Urumqi,China

利用乌鲁木齐市5座100m气象塔10层风速观测资料,分析了乌鲁木齐市城区和郊区近地层风速季节变化和日变化特征。结果表明:(1)乌鲁木齐市风速最大值出现在14:00—16:00,最小值多在夜间或上午。冬季风速最小、夏季最大;冬季风速始终处于较为稳定、有微小波动的低值区;夏季风速表现出一定的变化趋势。(2)夏季风速在一年里波动最大,随地势降低波动减小,南郊最大(1.5~6.4m·s^(-1)),北郊最小(1.3~4.6m·s^(-1));秋季和春季风速波动次之;冬季风速波动最小,南郊最大(1.3~4.6m·s^(-1)),北郊最小(0.7~2m·s^(-1))。(3)近地层100m内城区和北郊风速随高度变化较小,冬季基本为1~2m·s^(-1),而南郊风速随高度增加变化幅度最大,从1m·s^(-1)增加到4m·s^(-1)以上;愈近地面,城区与郊区风速相差愈大,近地面城区平均风速明显低于郊区,春季、夏季、秋季和冬季分别低5%~32%、8%~30%、15%~37%、14%~48%。(4)近地层风速廓线在近中性层结时一般符合对数风速廓线模式,对数律显著性不强的时段主要在正午前后。

The 10-layer wind speed data collected at five meteorological towers with100 m height in Urumqi were used to analyze the characteristics of the seasonal variation and diurnal variation of the wind speed in center and suburbs of Urumqi.The results show that：（1）The maximum value of wind speed appears at14：00-16：00,and the minimum value appears at night or in the morning.The maximum（minimum）wind speed is in summer（winter）.The wind speed in winter is relatively low and stable with small fluctuations.The wind speed change in summer.（2）The wind speed fluctuation is the strongest in summer,and the fluctuation decreases with terrain.The maximum fluctuation is in south suburb（1.5-6.4 m·s-1）,while the minimum is in north suburb（1.3-4.6 m·s-1）.The fluctuations in autumn and spring are followed.The fluctuation of wind speed is the weakest in winter,and the maximum is in south suburb（1.3-4.6 m·s-1）,and the minimum is in north suburb（0.7-2 m·s-1）.（3）The wind speed changes little with the height in0-100 m surface layer in center and north suburb,especially in winter.The wind speed increases from 1 m·s-1to 4 m·s-1 in 0-100 m surface layer in south suburb.The air flow is dragged strongly by the buildings when it is close to the ground.The wind speed near the ground in center is significantly lower than in suburb,and the differences are 5%-32% in spring,8%-30% in summer,15%-37% in autumn,14%-48% in winter.（4）Generally,the wind speed profiles are according to logarithmic function under near neutral stratification.While,the logarithmic function is not significant at noon.