The Earth Summit Mission-2022: Successful ozone soundings contribute to source identification in the north Mt. Qomolangma region.

As part of "The Earth Summit Mission-2022" during the second Tibetan Plateau Scientific Expedition and Research (STEP) in April and May 2022, we conducted the ozone sounding experiment (an ozonesonde mated to a radiosonde) at Mt. Qomolangma Base Camp (MQBC; 86.85°E, 28.14°N; 5200 m), a location at an extremely high altitude. A total of ten sounding profiles were obtained between April 30 and May 06, 2022, of which seven profiles were above 35 km in altitude, with a maximum detection altitude up to 39.0 km. This study presents the temporal variation and vertical distributions of atmospheric temperature, humidity, and ozone during the MQBC campaign. The averaged ozone concentration was high (68.3 ppbv) at the surface and then increased smoothly until peaking (∼110 ppbv) in the middle troposphere (approximately 10 km), and afterward, the ozone concentration increased rapidly from the upper troposphere to a maximum of ∼10 ppmv at ∼30 km. The enhanced ozone concentration in the middle troposphere was associated with the blocking high pressure, and transport from the southern flank of the Himalayas occurred during the campaign period. The average total ozone column was 291.9±21.4 DU for the seven profiles exceeding 35 km in altitude. The ozonesonde measurements were also compared with the vertical ozone profiles retrieved from the space-borne ozone products from the Microwave Limb Sounder (MLS) onboard the Aura satellite and the Atmospheric Infrared Sounder (AIRS) onboard the Aqua satellite.