Spatial and Temporal Distribution Characteristics and Causes of Aircraft Turbulence in Southwest China

利用2008年3月~2024年3月西南地区航空器空中报告，对西南地区飞机颠簸的特征和成因进行了探讨，得出以下结论：(1) 西南地区飞机颠簸的发生次数总体上呈现上升趋势，飞机颠簸冬春季发生次数多，夏秋少，白天多，早晚少；(2) 颠簸强度以中度颠簸为主，而冬春季相较夏秋季更容易出现中度及以上的颠簸；(3) 海拔较低的四川盆地和重庆地区颠簸主要发生在[2100, 6300) m，位于云贵高原东部的贵州地区颠簸主要出现在[4200, 6300) m，海拔更高的云南及西藏地区的颠簸则主要位于6300 m以上；(4) 高空急流是飞机颠簸的主要原因，对应高度主要分布在4200 m以上的中高层，高空槽对应的飞机颠簸集中在中层[4200, 6300) m，低空急流和中低层切变线造成的颠簸主要在低层[2100~4200 m)。Based on aircraft in-flight reports from March 2008 to March 2024 in the Southwest region, the characteristics and causes of aircraft turbulence in this area were explored, and the following conclusions were drawn: (1) The occurrence of aircraft turbulence in the Southwest region generally shows an upward trend. Turbulence occurs more frequently in winter and spring, less in summer and autumn, more during the day, and less in the early morning and evening. (2) Moderate turbulence is the predominant intensity. Compared with summer and autumn, winter and spring are more prone to moderate and above turbulence. (3) In the Sichuan Basin and Chongqing area with lower altitudes, turbulence mainly occurs in the range of [2100, 6300) m. In Guizhou area located in the eastern part of the Yunnan-Guizhou Plateau, turbulence mainly appears in the range of [4200, 6300) m. In Yunnan and Tibet areas with higher altitudes, turbulence is mainly located above 6300 m. (4) The jet stream is the main cause of aircraft turbulence, with the corresponding heights mainly distributed in the middle and upper layers above 4200 m. Turbulence associated with the trough of low pressure is concentrated in the middle layer [4200, 6300) m. Turbulence caused by low-level jet and low-level shear line mainly occurs in the lower layer [2100~4200) m.