中国西北地区逆温时空变化

Based on the data from 19 sounding stations in 2022-2023, this study investigates the temporal andspatial variations of the temperature inversions in the lower, middle and upper troposphere in northwest China.The results indicated the following: (1) In terms of monthly variations, inversions across all three troposphericlevels exhibit similar patterns, peaking in December and January-February of the following year and reaching a minimum from June to August. (2) In terms of spatial distribution, among the low-level inversions, low-level inversions were most frequent in northern Xinjiang, at 40%-60%; the greatest thickness of low-level inversions was observed in northern Shanxi, exceeding 90 m; the intensity of low-level inversions was stronger in most areas of Xinjiang, ranging from 2 and 3 . For mid-level inversions, their frequency was highest in Qinghai and decrease outward from this region. High-level inversions were most pronounced in northern Xinjiang, with their frequency decreasing outward from this region. (3) The occurrence of low-level inversions in northwest China is influenced by surface radiation and topography, the occurrence of mid-level inversions is associated with warm advection and subsidence movement, and the occurrence of high-level inversions may be related to the top of the temperate troposphere and ozone. (4) In the summer of northwest China, influenced by solar radiation and surface cooling. below the 0 isotherm height, the intensity of inversions is stronger; above the 0 isotherm height, the inversions have weaker intensity.