Ultraviolet Aerosol Index and Preliminary Near-UV Aerosol Optical Depth Retrievals from China's New-Generation Spaceborne Atmospheric Composition Detectors

China's two ultraviolet-visible atmospheric composition detectors — the Absorbing Aerosol Sensor (AAS), launched in 2021, and the Ozone Monitor Suite-Nadir (OMS-N), launched in 2023 — both provide daily global coverage. They are carried on the morning-orbit satellites GaoFen-5B and FengYun-3F, respectively, which enables mutual calibration between the two instruments. AAS offers a spectral resolution of 1.5 nm and a nadir spatial resolution of 2 km × 4 km, and is primarily designed to observe atmospheric aerosol pollution. OMS-N, in its main observation band, achieves a spectral resolution of 0.6 nm and a nadir spatial resolution of 7 km × 7 km. Its objectives include monitoring total ozone and its vertical profile, trace gases such as sulfur dioxide (SO₂), nitrogen dioxide (NO₂), and formaldehyde (HCHO), as well as retrieving aerosol and cloud information.Using wavelengths of 354 nm and 388 nm, we successfully obtained Ultraviolet Aerosol Index (UVAI) products from both payloads. These products were validated against GOME-2, which is also onboard a morning-orbit satellite, and the retrieval results from AAS and OMS-N were cross-compared. We utilized the UVAI products to observe pollution processes in the China region, the Indochina Peninsula, and the Indian region, as well as global dust belts and wildfire smoke plumes.We also obtained preliminary near-ultraviolet Aerosol Optical Depth (AOD) retrieval results using the OMAERUV method and validated them with AERONET data. The retrieval algorithm will be continuously refined going forward, and efforts will be made to acquire other aerosol products.