Potential changes in air quality in the Beijing Tianjin Hebei region under the RCP8.5 scenario using CCSM4/WRF-CMAQ dynamic downscaling estimation
At present, there is relatively little research on the impact of climate change on regional air quality, and statistical downscaling methods are often used to process global climate model results. The WRF mesoscale meteorological model is used to dynamically downscale the CMIP5 RCP8.5 scenario estimation results of the CCSM4 climate model, and to provide a meteorological field for the CMAQ air quality model; Based on the 2012 Tsinghua University MEIC atmospheric pollutant emission inventory, 2005 was selected as the representative year for climate status and 2049-2051 as the future climate representative year. The meteorological and air quality numerical simulation results of typical months (January, April, July, and October) in the Beijing Tianjin Hebei region were compared to estimate the potential changes in air quality in the Beijing Tianjin Hebei region under the background of climate change. The results showed that under the unchanged emission situation and the RCP8.5 scenario, Compared with the current representative year, the average annual meteorological factors in the Beijing Tianjin Hebei region, represented by typical months, show an overall trend of temperature increase, while wind speed, relative humidity, and atmospheric boundary layer height all decrease; The annual average concentration of atmospheric pollutants shows an overall upward trend, with temperatures increasing by about 0.8 ℃, wind speeds decreasing by about 0.11 m/s, relative humidity decreasing by about 2%, and atmospheric boundary layer height decreasing by about 8 m, ρ (PM2.5) increase by approximately 2.4 μ G/m3, ρ (SO2) increases by approximately 1.8 μ G/m3, ρ (NOx) increases by approximately 1.0 μ G/m3; In addition, among the main meteorological conditions (temperature, wind speed, relative humidity, atmospheric boundary layer height), the decrease in wind speed and atmospheric boundary layer height may be the main meteorological factors causing changes in the concentration of these atmospheric pollutants, and the decrease in wind speed and atmospheric boundary layer height is related to ρ The correlation coefficients of (PM2.5) reduction are approximately -0.44 and -0.26, respectively. Studies have shown that climate change poses a potential risk of increasing pollutant concentrations in the Beijing Tianjin Hebei region. At the same time, due to the lack of future emission scenario data for air quality models and the increasing improvement of online coupling models, deeper research is urgently needed in the field of climate air quality research in China