不同代表性浓度路径情景下2045-2050年中国气溶胶分布变化的分析

基于来自于CMIP5中CESM模式的三种RCP情景下的气象场的降尺度模拟,应用区域空气质量模式系统RAMS-CMAQ模拟2045-2050年中国地区气溶胶浓度.三种RCP情景下气象场的降尺度模拟表明,与RCP2.6相比,在RCP4.5和RCP8.5下,华北和华南的近地表温度差减小,风速在华北和华南地区增加,在中部地区下降.RCP2.6情景下,模拟的2045年到2050年平均的PM 2.5浓度在华北平原,长三角的部分地区和四川盆地最高,约为40-50μg m-3,在中国中部和珠三角的部分地区约为30-40 μg m-3.与RCP2.6相比,在RCP4.5和RCP8.5下,PM2.5增加了4-12μgm-3,其中在RCP4.5和RCP8.5下,SO42-和NH4+的浓度增加,在RCP4.5下,NO3-浓度降低,在RCP8.5下,NO3-浓度升高,在RCP4.5和RCP8.5下,BC浓度变化很小,而OC浓度下降,其中在RCP8.5下,西南和东南部分地区的OC有所增加.不同的气溶胶物种浓度在RCP4.5和RCP2.6之间的差异以及RCP8.5和RCP2.6之间的差异具有相似的年度变化,这表明气候变化对不同物种的影响趋于一致.

Analysis of aerosol distribution variations over China for the period 2045-2050 under different Representative Concentration Pathway scenarios

The regional air quality modeling system RAMS-CMAQ was applied to simulate the aerosol concentration for the period 2045-2050 over China based on the downscaled meteorological field of three RCP scenarios from CESM(NCAR's Community Earth System Model)in CMIP5.The downscaling simulation of the meteorological field of the three RCP scenarios showed that,compared with that under RCP2.6,the difference in near-surface tempera-ture between North and South China is weakened and the wind speed increases over North and South China and decreases over central China under RCP4.5 and RCP8.5.Under RCP2.6,from 2045 to 2050,the modeled average PM2.5 concentration is highest,with a value of 40-50 μg m-3,over the North China Plain,part of the Yangtze River Delta,and the Sichuan Basin.Meanwhile,it is 30-40 μg m-3 over central China and part of the Pearl River Delta.Compared with RCP2.6,PM2.5 increases by 4-12 μg m-3 under both RCP4.5 and RCP8.5,of which the SO42-and NH4+concentration increases under both RCP4.5 and RCP8.5;the NO3-concentration decreases un-der RCP4.5 and increases under RCP8.5;and the black carbon concentration changes very slightly,and organic carbon concentration decreases,under RCP4.5 and RCP8.5,with some increase over part of Southwest and South-east China under RCP8.5.The difference between RCP4.5 and RCP2.6 and the difference between RCP8.5 and RCP2.6 have similar annual variation for different aerosol species,indicating that the impact of climate change on different species tends to be consistent.