Effect of large topography on atmospheric environment in Sichuan Basin: A climate analysis based on changes in atmospheric visibility

Using 51 years (1960–2010) of observations from meteorological stations in the Sichuan-Chongqing region, including atmospheric visibility as a proxy for aerosol concentration, relative humidity, air temperature, wind speed and FNL reanalysis data (1°×1°) pressure wind, altitude each station, linear trend multivariate fitting approach was used to explore effects large topography on environment region. The region mainly consists two areas: Sichuan Basin (SCB) Western Plateau (WSP; eastern part Tibetan Plateau). Visibility relatively low SCB high WSP, indicating levels aerosols respectively WSP. Additionally, were positively correlated within basin (altitude below 750 m), while negatively at above 1,500 m, such that had an influence basin. On one hand, vertical structures fields profiles latitudinal deviations temperature show unique causes “harbour” effect leeward-slope with being weak descending currents upper westerlies form huge “vault” air. other topographic can make more susceptible formation inversion near surface altitudes, thus stabilising atmosphere. effects, which is not conducive horizontal diffusion convective transport pollutants, most significant winter, followed by autumn spring.