ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Archive > Volume 50 Issue 12 > 2024,50(12):1495-1508. DOI:10.7519/j.issn.1000-0526.2024.101501 Prev Next
Analysis on the Characteristics of Thunderstorm Gale in Jiangxi Province During 2015-2023
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Abstract:
The spatio-temporal distribution of thunderstorm gales (TGs) in Jiangxi is comprehensively analyzed based on hourly observation data of automatic weather stations, cloud-to-ground lightning observations and weather radar data in Jiangxi Province from 2015 to 2023. The ERA5 reanalysis data are further used to investigate the atmospheric environment before the onset of TGs. The results show that the TGs in Jiangxi occur mainly in spring and summer, with significant seasonal variations and differences in the north-central part and the south. The frequency of TGs occurring in spring is only slightly higher than in summer in north-central Jiangxi, but the frequency of TGs in summer is more than twice of that in spring in the south of Jiangxi. TGs have obvious diurnal variation with the highest occurrence frequency from 14:00 BT to 20:00 BT. The frequency of TGs from evening into night in north-central Jiangxi is much higher than in the southern part. The thermodynamic, dynamic and water vapor characteristics of TGs are significantly different in spatio-temporal distributions. In the same season, the dynamic effect is generally stronger in north-central Jiangxi than in the southern part, while the thermodynamic and water vapor effects are stronger in the south than in north-central part. The thermodynamic and water vapor effects are stronger in summer than in spring, but the dynamic effect in spring is stronger. The convective instability energy required for TGs varies by time periods, but all occur under unstable conditions. TGs occur more frequently under low vertical wind shear in the afternoon and also in the deep night with strong vertical wind shear conditions. Besides, the upper-level dry and low-level wet structure in the daytime is more pronounced than at night. Therefore, it is crucial to set ambient parameter thresholds by season, region and time period, in order to provide more accurate guidance on TGs forecast and warning. When 0-6 km vertical wind shear (Shear6) is large enough and distributed in the range of 30-33 m·s-1 in spring in north-central Jiangxi, it is imperative to be alert to the advent of TGs even if most unstable convective available potential energy (MUCAPE) is only in the range of 0-500 J·kg-1 and precipitable water (PW) only in the range of 43-48 mm. To accurately forecast the occurrence of TGs in summer, it is essential to pay attention to the MUCAPE and PW, and especially in the south of Jiangxi, TGs tend to occur with higher frequency under weak mid-level vertical wind shear. When PW>60 mm and MUCAPE>1500 J·kg-1, even though Shear6 is minimal and confined to a range of 5-8 m·s-1, it is necessary to contemplate the potential for TGs. The increase of water vapor is important for the occurrence of TGs in different regions during different seasons. Therefore, changes in PW should be focused on in the operation of forecasting TGs.
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