Characteristics of Bow Echoes During 2011–2020 in Western South China (Guangxi)

Based on previously released data, this paper first presented the criteria for recognizing bow echoes and divided their life cycle into three stages: the development stage, the mature stage, and the attenuation stage. Based on Doppler weather radar data during 2011–2020, 43 bow echo events (including 54 individual bow echoes) in western South China were identified. The spatial and temporal distributions, formation and dissipation modes of these bow echoes, and the severe weather they caused were statistically analyzed. The results show that: (1) The bow echo events were unevenly distributed year-to-year, but all occurred from March to July, with the highest in April and May and the lowest in July. The period from night to early morning was found to be the main period for bow echo generation and intensification. (2) A banded area from Hechi City on the southeastern edge of the Yunnan–Guizhou Plateau to Wuzhou City in southeast Guangxi was identified as a high-incidence area of bow echoes. The length of bow echoes was correlated with their life cycle. (3) The origins of the bow echoes could be divided into five locations, most of which were in the eastern Yunnan– Guizhou Plateau. After entering western South China, their moving paths were categorized into three types, among which most bow echoes moved southeastward, generally because of the effect of cold air. Specifically, bow echoes generally moved eastward when cold air was weak or in the warm zone. Meanwhile, the fewest bow echoes moved northeastward. (4) Four modes of bow echo formation were identified: linearly organized, broken areal, linearly merging, and broken line. Dissipation could also be classified into four types. (5) The probability of convective weather generated by a bow echo was largest in the mature stage.