Abstract: Using the radiosonde data obtained during the 9th Chinese National Arctic Research Expedition (CHINARE 2018), the atmospheric structure characteristics over the Arctic Ocean during the observation period were analyzed. The results show that: (1) The average of temperature lapse rate in the middle troposphere was 5.67°C·km⁻¹, which was consistent with that over the central Arctic. The characteristics of high-level jets were remarkable, especially over the high latitude region. (2) The medians of the height of the boundary layer temperature inversion base, the depth of the inversion and the temperature change through the inversion were 306 m, 299 m and 3.2°C, respectively, which were consistent with SHEBA(Surface Heat Budget of the Arctic Ocean). (3) The medians of the height of the low-level jet core and the wind speed in the core were 456 m and 11.40 m·s⁻¹, respectively, and the wind speed of the jets was mostly distributed within 6–14 m·s⁻¹. (4) Only 67.27% of the low-level jets were below the lowest inversions. However, considering multiple temperature inversion layers, 92.73% of the low-level jets were beneath the top of the inversions.

Key words: Arctic, lower atmosphere, boundary layer temperature inversion, low-level jet