Analysis of spatiotemporal variation of formaldehyde column concentration in Qinghai-Tibet Plateau and its influencing factors

Based on the formaldehyde (HCHO) inversion data of OMI satellite sensor from 2009 to 2019, this paper discusses the spatial and temporal distribution of HCHO column concentration over the Qinghai-Tibet Plateau in the past 11 years and explores the factors affecting the dynamic distribution of atmospheric HCHO column concentration over the Qinghai-Tibet Plateau in combination with meteorological, aerosol, ozone, and other data. The results show that the average concentration of HCHO column in the Qinghai-Tibet Plateau is 8.84 × 10¹⁵ molec/cm² in the past 11 years, which is relatively low, and the annual variation rate of HCHO column is 7.79%, showing a slight upward trend. The seasonal changes show a trend of Autumn < Winter < Spring < Summer. The monthly variation is more obvious than the seasonal variation. The spatial distribution showed a decreasing trend from southeast to northwest. Residual analysis showed that 83.77% of the area was frequently affected by natural factors. Correlation analysis found that the natural factors including precipitation, air temperature, and atmospheric activities for a greater influence on the column experiment the distribution of the concentration of the Qinghai-Tibet Plateau and human factors, such as biomass, the distribution of fossil fuel combustion, and emissions to HCHO, play a promoting role. Through the backward trajectory analysis, it can be seen that the transboundary atmospheric transport activity has a prominent contribution to the distribution of HCHO in the southern region of the Qinghai-Tibet Plateau. Hurst index study found that in the future, the concentration of HCHO column in 53.03% of the Qinghai-Tibet Plateau will decrease, but in some areas, such as the eastern and northern parts of the Qinghai-Tibet Plateau, it will increase.