利用气象铁塔湍流观测、 能见度仪、 自动气象站以及其他气象资料， 分析了天津城区秋季雾天气过程中低层大气层结演变及温度、 湿度和风速湍流统计特征。结果表明, 不稳定层结条件下， 下垫面温度、 湿度均一化标准差随稳定度程度加强而呈减弱趋势， 数值显著高于Kansas草原及农田下垫面， 变化规律不能用经典湍流相似性理论描述； 而风速归一化标准差数值随稳定度的变化符合近地面经典湍流相似性理论， 中性层结条件下的各方向风速归一化标准差分别为2.5, 1.9和1.2。稳定层结条件下， 温度和湿度均一化标准差离散， 风速没有明显的离散。另外， 城区浓雾过程中， 大气层结由雾前的强稳定转为雾中的偏中性层结， 雾形成前， 稳定度数值集中在-10～10之间； 雾期间， 在-2～2之间变化， 变化范围较窄； 雾消散后， 在-5～10之间变化。
Based on the turbulent data, wind, temperature, relative humidity and visibility data at 250 m meteorological tower in Tianjin city, the turbulence characteristics of atmospheric surface layer during autumn fog were discussed. The results show that the normalized standard deviations of temperature and humidity over urban area decrease with increasing instability under unstable conditions and the values are obviously larger than those over Kansas prairie and cropland, which cannot obey classical Monin-Obukhov similarity theory. However, the normalized standard deviations of three dimensional wind velocities in unstable conditions increase with instability and obey a 1/3 power law of Monin-Obukhov similarity theory during autumn fog, with their values being 2.5, 1.9 and 1.2, respectively for three directions in the condition of near neural stratification. The scatter of normalized standard deviations of temperature and humidity increases under stable stratification conditions, while it is not obvious for wind velocity. During the dense fog process over the urban area, atmospheric stratification changes from strong stable before fog to near-neutral stratification during the fog. Prior to the fog formation, the range of stability parameter is from -10 to 10.The value varies from -2 to 2 on a smaller scale during the fogprocess. It varies between -5 and 10 after fog dissipation.
[1]吴彬贵, 张宏升, 汪靖, 等. 一次持续性浓雾天气过程的水汽输送及逆温特征分析[J]. 高原气象, 2009, 28(2): 258-267.
[2]张恒德, 饶晓琴, 乔林. 一次华东地区大范围持续雾过程的诊断分析[J]. 高原气象, 2011, 30(5): 1255-1265.
[3]Roth M. Turbulent transfer relationships over an urban surface. II Integral statistics[J]. Quart J Roy Meteor Soc, 1993, 119(513): 1105-1120.
[4]刘熙明, 胡非, 邹海波, 等. 北京地区一次典型大雾天气过程的边界层特征分析[J]. 高原气象, 2010, 29(5): 1174-1182.
[5]Duynkerke P G. Turbulence, radiation and fog in dutch stable boundary layers[J]. Bound-Layer Meteor, 1999, 90(3): 447-477.
[6]Klipp C. Wind direction dependence of atmospheric boundary layer turbulence parameters in the urban roughness sublayer[J]. J Appl Meteor Climatol, 2007, 46(12): 2086-2097.
[7]Christen A, Rotach M W, Vogt R. The budget of turbulent kinetic energy in the urban roughness sublayer[J]. Bound-Layer Meteor, 2009, 131(2): 193-222.
[8]Zhou B, Ferrier B S. Asymptotic analysis of equilibrium in radiation fog[J]. J Appl Meteor Climatol, 2008, 47(6): 1704-1722.
[9]Sun J L, Lenschow D H, Burns S P, et al. Atmospheric disturbances that generate intermittent turbulence in nocturnal boundary layers[J]. Bound-Layer Meteor, 2004, 110(2): 255-279.
[10]黄健, 王斌, 周发琇, 等. 华南沿海暖海雾过程中的湍流热量交换特征[J]. 大气科学, 2010, 34(4): 715-725.
[11]张宏升, 康凌, 张霭琛. 大气湍流数据处理系统及计算方法的讨论[J]. 气象水文海洋仪器, 2001, 18(2): 1-11.
[12]吴彬贵, 张宏升, 张长春, 等. 华北地区平流雾过程湍流输送及演变特征[J]. 大气科学, 2010, 34(2): 440-448.
[13]黄鹤, 蔡子颖, 韩素芹, 等. 天津市PM10, PM2.5和PM1连续在线观测分析[J]. 环境科学研究, 2011(8): 897-903.
[14]Wyngaard J C, Cote O R, Izumi Y. Local free convection, similarity, and budgets of shear stress and heat flux[J]. J Atmos Sci, 1971, 28(7): 1171-1182.
[15]Wyngaard J C, Cote O R. Budgets of turbulent kinetic energy and temperature variance in atmospheric surface layer[J]. J Atmos Sci, 1971, 28(2): 271-284.
[16]De Bruin H R, Kohsiek W, Van Den Hurk B J J M. A verification of some methods to determine the fluxes of momentum, sensible heat, and water vapour using standard deviation and structure parameter of scalar meteorological quantities[J]. Bound-Layer Meteor, 1993, 63(3): 231-257.
[17]张宏升, 李富余, 陈家宜. 不同下垫面湍流统计特征研究[J]. 高原气象, 2004, 23(5): 598-604.
[18]Hogstrom U. Field study of turbulent fluxes of heat, water-vapor and momentum at a typical agricultural site[J]. Quart J Roy Meteor Soc, 1974, 100(426): 624-639.
