混合层厚度的经验计算及与探空观测对比分析  

Comparisons of Boundary Mixing Layer Depths Determined by the Empirical Calculation and Radiosonde Profiles

作　　者：马金[1] 郑向东[1] 

机构地区：[1]中国气象科学研究院,北京100081

出　　处：《应用气象学报》2011年第5期567-576,共10页Journal of Applied Meteorological Science

基　　金：国家重点基础研究发展计划项目(2005CB422202)

摘　　要：根据Nozaki计算混合层厚度的经验参数化方法,利用部分时段的北京、黑龙江龙凤山、浙江临安、新疆阿勒泰、海南三亚、青海西宁、云南腾冲7个站的地面常规气象观测资料,计算14:00(北京时)的混合层厚度,并与短期的臭氧探空资料中的Vaisala RS-80气象探空仪观测资料(位温廓线和折射系数梯度)分别确定的混合层厚度作对比分析。结果表明:由气象探空资料位温廓线和折射系数梯度分别确定的混合层厚度一致性很好,同时用这两种方法可以较为准确地确定混合层厚度。Nozaki方法可以较好地揭示混合层厚度日变化特征;但是当混合层厚度大于2000 m时,该方法计算值偏小,而小于1000 m时稍偏大;该方法计算值在北方站点(北京、龙凤山、阿勒泰、西宁)偏高,南方站点(三亚、临安、腾冲)偏低,而且计算值在无云时误差较大,多云时误差较小。Mixing layer is one typical type of atmosphere boundary layer, and it is named after strong vertical mixing which leads to the nearly constant variables, such as potential temperature and water vapor in this layer. The depth of mixing layer is an important parameter to identify features of thermodynamics and at mospheric dynamics in the boundary layer, and also a key to monitor the air quality. Mixing layer has very distinct daily variation as different meteorological conditions and synoptic processes largely influence the structure of boundary layer. Mixing layer becomes thicker under clear sky conditions, while remains phys ically stable and almost invariant during a single day under cloudy or raining weather conditions. Therefore, measurements and calculation of mixing layer depth are worth studying. The depths of mixing layer at 14：00 of Beijing, Longfengshan, Lin＇an, Aletai, Sanya, Xining and Tengchong are compared using two kinds of datasets. The Nozaki empirical method and the radiosonde ob servational data reduced by vertical profiles of potential temperature and refractivity. It shows that the two observational depths are in good agreement, and the radiosonde measurements of mixing layer can be seen as criteria in the comparison with the Nozaki empirical method. Few bad linear correlation points of mixing layer depth from potential temperature profiles and refractivity profiles indicate that depth of mixing layer determined by refractivity profiles sometimes cannot find out the actual mixing layer, possibly due to dra- matic variation of refractivity profiles under stable atmosphere vertical structure conditions. The comparisons illustrate that the Nozaki method may reflect the daily variations of mixing layer as those shown in observational dataset. However, the Nozaki method underestimates mixing layer depth when the mixing layer is above 2000 m. On the contrary~ it overestimates mixing layer depth when the mixing layer is lower than 1000 m. Nozaki method also overestimates mixing layer depth at

关 键 词：混合层厚度 Nozaki方法 位温廓线法 折射系数法 

分 类 号：P413[天文地球—大气科学及气象学]