乌鲁木齐市城区和郊区湍流特征

Characteristics of Turbulence in Urban and Suburban Areas of Urumqi

利用乌鲁木齐市4座100 m气象塔2013年6月至2014年4月46 m三维超声风速观测资料,计算湍流统计特征值并进一步详细分析乌鲁木齐市近地层湍流特征,得出以下结果:乌鲁木齐南郊摩擦速度u*平均值为0.37 m·s^(-1)、城区平均0.28 m·s^(-1)、近北郊和北郊平均0.23 m·s^(-1),春夏季大、冬季小,南郊、城区、近北郊和北郊春季最大分别为0.75、0.64、0.51和0.50 m·s^(-1),冬季最大分别为0.56、0.26、0.22和0.23 m·s^(-1);南郊湍流动能TKE平均1.38 m^2·s^(-2)、城区平均0.7 m^2·s^(-2)、近北郊和北郊平均0.6 m^2·s^(-2),春夏季大、冬季小,南郊、城区、近北郊和北郊春季最大分别为3.39、2.22、1.88和1.79 m^2·s^(-2),冬季最大分别为2.82、0.44、0.45和0.33 m^2·s^(-2)。三个方向湍流强度呈现Iu≈Iv>Iw的规律,南郊0.11~0.36、城区0.12~0.37、近北郊0.10~0.36、北郊0.13~0.39。各个季节南郊白天u*和TKE最大,表明南郊湍流垂直扩散能力最强。

The characteristics of turbulence in the near-surface layer were calculated and statistically analyzed based on the three-dimensional velocity data obtained from four 100 m meteorological towers in Urumqi from June 2013 to April 2014. The results showed that the average frictional velocities in the southern suburban,urban and northern suburban and northern rural area were 0. 37,0. 28 and 0. 23 m·s^（-1）,respectively. The variation of frictional velocity was strong in spring and summer,while it was weak in winter. The maximum frictional velocity in the southern suburban,urban,northern suburban and northern rural area in spring was 0. 75,0. 64,0. 51 and 0. 50 m·s^（-1）,respectively,in winter it was 0. 56,0. 26,0. 22 and 0. 23 m·s^（-1）,respectively. Turbulent kinetic energy TKE in the southern suburban,urban and northern suburban and northern rural area were 1. 38,0. 7 and 0. 6 m^2·s^（-2）,respectively.Also,the turbulent kinetic energy TKE was strong in spring and summer,while it was weak in winter. The maximum turbulent kinetic energy in the southern suburban, urban, northern suburban and northern rural area in spring was 3. 39,2. 22,1. 88 and1. 79 m^2·s^（-2）,respectively,in winter it was 2. 82,0. 44,0. 45 and 0. 33 m^2·s^（-2）,respectively. Turbulence intensity in three directions were Iu≈Iv Iw,with 0. 11-0. 36,0. 12-0. 37,0. 10-0. 36 and 0. 13-0. 39 in the southern suburban,urban and northern suburban and northern rural area. At the day time,u＊and TKE were strong in all seasons in the southern suburban,which revealed that vertical diffusion was the strongest in the southern suburbs.