PRELIMINARY SENSITIVITY STUDY OF AEROSOL LAYER HEIGHT FROM SYNTHETIC MULTIANGLE POLARIMETRIC REMOTE SENSING MEASUREMENTS

Understanding greenhouse gas and air pollutant concentrations and emissions characteristics in the Qinghai-Tibetan Plateau cities remains limited. We present the first CO₂, CH₄ and CO abundances using a portal Fourier-transform infrared (FTIR) spectrometer in Xining. Ground-based data exceeded satellite/model estimates, indicating higher local emissions. Strong CO discrepancies and ∆XCO–∆XCO₂ correlation under easterly winds highlight the value of portable FTIR for urban emission studies.

Pyrocumulonimbus (PyroCb) convection during the August 2024 North American wildfires injected smoke aerosols into the upper troposphere and lower stratosphere, altering cloud microphysics. These aerosols induced warming near fire sources and downwind over Western Europe, while producing contrasting effects over fire-source regions, cooling along the US West Coast and warming across North America, demonstrating strong wildfire-aerosol-cloud-radiation feedbacks with transcontinental impacts.

A global AOD product from Particulate Observing Scanning Polarimeter (POSP) has been proposed and validated using Aerosol Robotic Network (AERONET). Results show a high accuracy, with correlation coefficients (R) of 0.914, a root mean square error (RMSE) of 0.085, outperforming Moderate Resolution Imaging Spectroradiometer (MODIS). Error analysis reveals seasonal variation with lower accuracy in autumn/winter, and increased uncertainty with lower Normalized Difference Vegetation Index NDVI.

This study describes the analysis of time series of the MODIS-derived aerosol optical depth (AOD) over China between 2010 and 2024. Emission reduction policies were effective with respect to reducing the AOD until 2018. Thereafter, the overall reduction until the end of the study was very small due to unfavorable meteorological factors cancelling favorable anthropogenic effects and resulting in an AOD increase during extended periods. The variations over different areas in China are discussed.

Nitrogen dioxide (NO₂) is a major pollutant that, at high concentrations, may affect human health. We evaluated the remote sensing column NO₂ in relation to near-surface concentrations throughout the day and found that the prohibition of vertical transport in the morning and the mixing in the afternoon resulted in different relations between the near-surface (NS) and total column NO₂ concentrations. These different relationships have consequences for the use of satellite remote sensing to estimate NS NO₂ concentrations.