基于1998 年中国南海季风实验期间(5 月5—25 日,6 月5—25 日)科学#1 号考察船上的高分辨率气球探空数据,分别采用Thorpe 分析方法和利用气球垂直上升速度的扰动计算湍流参数的方法,计算对流层和低平流层湍动能耗散率ε和湍流扩散系数K。Thorpe 分析法是从温度的角度考虑,根据Thorpe 尺度LT与湍流参数之间的关系计算湍流参数,而利用垂直上升速度的扰动计算湍流参数的方法是从速度的角度考虑,利用垂直上升速度的扰动σW与湍动能耗散率ε之间的关系计算湍流参数。通过对两种方法及其计算结果进行比较发现:在垂直结构方面,不论是月平均结果还是日平均结果,两种方法计算出的ε和湍流扩散系数K 均是在10 km 以上而在对流层顶以下较大,在对流层顶以上较小;两种方法计算出的K 的峰值高度均在15 km 左右;在数值范围方面,ε的取值均在10-6 ~10-2 m2·s-3,K 的取值均在0~10 m2·s-1,但是采用垂直上升速度的扰动计算湍流参数的方法求得的湍流参数小于Thorpe 分析方法得到的湍流参数;峰值高度方面,采用Thorpe 分析方法所得ε的峰值高度在15 km 左右,而采用垂直上升速度扰动方法所得ε的峰值高度在17 km 左右。
On the basis of the high resolution wind and temperature data observed by the radiosound on the Kexue #1 scientific observation ship during SCSMEX (South China Sea Monsoon Experiment) in 1998 (May 5-25, June 5-25), the turbulence parameters (kinetic energy dissipation rate ε and turbulence diffusivity K) in the troposphere and lower stratosphere (TLS) are derived using the following two methods: Thorpe analysis, which calculates the turbulence parameters on the basis of the temperature data and Thorpe length LT, and the vertical velocity fluctuation method, which calculates the turbulence parameters on the basis of vertical velocity data and their fluctuations σW. The results from the two methods exhibit similarities in terms of the vertical structure and magnitudes of ε and K. In the respect of vertical structures, ε and K are relatively large above 10 km and below the tropopause (~17-18 km), no matter the averaged results are on a monthly or daily basis. By contrast, they are relatively small above the tropopause. The peak values of K derived using the two methods are both at around 15 km. The magnitudes of ε and K calculated using the two methods are both in the range of 10-6-10-2 m2·s-3 for ε and 0-10 m2·s-1 for K. The differences of the results from the two methods are that the turbulence parameters calculated by the vertical velocity fluctuation method are smaller than those by Thorpe analysis; the peak value of ε is at about 15 km according to Thorpe analysis, but at about 17 km according to the vertical velocity fluctuation method.
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