基于高精度的排放源和大气化学模式WRF/chem,在同排放源条件下模拟了2000~2015年天津地区PM2.5质量浓度,根据NECP再分析资料和地面观测相关数据构建细颗粒物气象扩散指数,使用两种方法描述21世纪以来天津地区细颗粒物气象扩散能力变化趋势.研究结果表明:2000~2015年期间天津地区细颗粒气象扩散能力呈现周期性波动,不利气象条件的第一个峰值出现在2003~2004年,第二个峰值为2013~2015年,两个峰值相距11年,在2000~2015年间,天津地区气象扩散能力(主要针对PM2.5影响)年际平均波动4.1%,最大值约为9%,对于大气污染防治目标制定和效果评估,必须考虑气象年际波动的影响;2008~2010年气象条件较有利于细颗粒物扩散,此后逐年转差,在2013~2015年处于历史正距平(不利扩散),从而导致2013~2015年雾霾和重污染天气频发;2015年相比2013年天津细颗粒物气象扩散能力没有明显提高,但PM2.5质量浓度下降29%,大气污染防治措施的有效执行在其中发挥积极作用.%Two method was used to analysis the trend of meteorological diffusivity for fine particulate in Tianjin since 2000. One is simulating PM2.5 mass concentration by WRF/chem in Tianjin from 2000 to 2015 with same high precision emission. The other is analyzing a fine particulate meteorological diffusion index constructing from NCEP data and ground observation. There is an obviously periodic fluctuation of meteorological diffusivity for fine particulate from 2000 to 2015. There are two peak of low meteorology diffusivity. The first one is from 2003 to 2004 and another is from 2013 to 2015. There are 11 years interval between the two peaks. The inter annual variability for meteorological diffusivity of fine particulate has a averaged 4.1% value and max 9%value. The inter annual variability must be considered for atmospheric pollution control and evaluation. The good meteorological diffusivity for fine particulate is from 2008 to 2010. After that, the meteorological diffusivity get worse year by year and reach peak value from 2013 to 2015 which causing the frequently haze and heavy pollution weather. Comparing with 2013, the observed PM2.5 mass concentration decreased 29% on 2015 with same meteorological diffusivity. It implies that the atmospheric pollution control method worked effectively. comprehensive meteorological diffusion function, described the change tendency of the 21st century polluted meteorological conditions. The result showed: The polluted meteorological conditions Showed the cycle fluctuation form 2000 to 2015, the first peak of adverse weather conditions was 2003~2004, the second peak of adverse weather conditions was 2013~2015, the apart of two peaks was 11 years. Inter annual fluctuation of The polluted meteorological conditions (mainly for PM2.5) was about 4.1%, the maximum was about 9%, The goal and effect of atmospheric pollution control was set, meteorological cycle fluctuations must be considered. Polluted meteorological conditions was conducive to atmospheric pollutants diffusion from 2008 to 2010, then turn worse year by year, which led to haze and heavy pollution weather frequent form 2013~2015. Compared to 2013, Tianjin pollution meteorological was not turned for the better on 2015, but PM2.5 dropped 29%. Atmospheric pollution control was effective on Tianjin.
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