Statistical Analysis of Turbulence Characteristics over the Tropical Western Pacific Based on Radiosonde Data

Abstract

The tropical region is a key area for the interaction between the stratosphere and troposphere. The strong convective activity in the troposphere produces a series of gravity wave activities, which result in strong and widespread turbulence over the region. Therefore, studying the turbulent activity in the western Pacific is essential for understanding the characteristics of atmospheric disturbance over this region, which has the world’s most complex circulation system. In this paper, we explore the characteristics of atmospheric turbulence distribution over Guam in this region, and the Thorpe sorting method is used to study one-second resolution radiosonde data from the US. On the basis of the background field and local instability, the turbulence generation mechanism is discussed in detail. Results show that the US high-resolution balloon data are efficacious for tropospheric turbulence retrieval but increasingly affected by instrument noise as altitude increases. It is also found that there is a strong turbulent mixing band caused by both shear instability and static instability near the tropopause, where the turbulence activity is markedly enhanced and characterized by annual oscillation, reaching the maximum from July to September.

A case analysis of turbulence characteristics and ozone perturbations over eastern China

“…The Thorpe scale (L T ) is calculated by obtaining the root mean square value of the displacement. L T shows the local overturning scale in the atmosphere column (Crawford, 1986;Riley and Erik, 2008) and is related to the Ozmidov scale (L 0 ), which describes turbulence in a stably stratified fluid and can be expressed as follows (He et al, 2020b):…”

Statistical Characteristics of Inertial Gravity Waves Over a Tropical Station in the Western Pacific Based on High‐Resolution GPS Radiosonde Soundings

“…The reason is that in monsoon, the maximum values of turbulence parameters (turbulent scale, turbulent energy dissipation rate and turbulent diffusion coefficient) are concentrated at 14–16 km, and the IGWs extracted in this paper avoid the height interval near the tropopause. Therefore, the significant enhancement of turbulent activity in this area has no clear relationship with the activity of the IGW extracted in the troposphere, but is due to strong wind shear and static instability (He, Sheng, Zhou, et al., 2020).…”

“…In previous work, statistical analysis has been carried out on the characteristics of turbulence activity in the Western Pacific (He, Sheng, Zhou, et al., 2020), and it is found that turbulence mainly occurs in the middle and upper troposphere (10–16 km), with thermal and shear instability co‐existence. At the same time, the turbulent activity near the tropopause forms a “strongest mixing zone”, which is strengthened from July to September (monsoon), while the turbulent activity of the corresponding season is significantly weaker in the middle and lower troposphere compared with other seasons.…”

“…The balloons are released twice a day at 0:00UT and 12:00UT. We only selected night data here, the purpose is to facilitate the comparison with the results of IGWs observation in Gadanki station based on night data, as well as the comparison with the turbulence characteristics over Guam (He, Sheng, Zhou, et al., 2020), and to eliminate the interference of the instrument noise in the daytime for harmonic fitting of the profile (He et al., 2021). The average rate of balloon ascent is 6 m/s, 91.5% of the detection profile exceeds 25 km, and 84.28% of the detection profile exceeds 30 km.…”

Case Analysis of Turbulence From High-Resolution Sounding Data in Northwest China

“…In turn, precipitation can be predicted to a certain extent through changes in atmospheric turbulence. It is of great significance to improve the accuracy of weather forecast and numerical weather model (He et al, 2020b).…”