| Jiangsu province is one of the economically strong provinces in east China.With the advance of the modernization process,the problem of air pollution in this area is facing a severe challenge under the common role of human activities and regional climate change.In this paper,based on the observations of the primary air pollutants and meteorological elements from 2014to 2018,the spatial and temporal distribution characteristics of Jiangsu AQI and primary air pollutants(PM2.5,PM10,SO2,NO2,O3,and CO)were analyzed,and the relationship between air pollution and major meteorological factors was obtained.On the basis of statistical analysis and combining with RegCM4（Regional Climate Model,version 4）to establish statistical estimation method,and at the same time,RegCM-CHEM4（Regional Climate Chemistry Model,version 4）was used for the numerical simulation of pollutants,finally,to simulate and predict the winter of 2020 air quality and air pollutant concentration change in Jiangsu province,to explore the future temperature changes on the effect of sulphate aerosols in Jiangsu,and to analyze the radiation forcing role of anthropogenic aerosols（sulfate,organic carbon,black carbon）,and to explore the regional climate effect of aerosols in Jiangsu.The main findings are as follows:（1）In terms of temporal change,the characteristics of different pollutants in Jiangsu province are different.From 2014 to 2018,the concentrations of AQI,PM10 and PM2.5,SO2 and NO2 showed a yearly decreasing trend,while that of O3 was increasing.In 2018,compared with2014,the concentrations of AQI,PM10,PM2.5,SO2 and NO2 decreased by 20.1%,26.3%,30.2%,59.3%and 6.3%,respectively,While the O3 increased by 12%compared with 4 years ago.For the seasonal change,with the exception of O3,the seasonal variation of the concentration of all the other pollutants was high in winter and low in summer,the average concentration of AQI,PM2.5 and PM10 in winter was about twice than that in summer.However the seasonal variation of O3 was the opposite.From the monthly average of these 5 years,also with the exception of O3,the monthly variation trend of AQI and all the other concentration of various pollutants was consistent and showed a"U"shape,the months with high concentration were mainly concentrated in December and January,and in July,August and September,the values were relatively low.The monthly variation trend of O3 concentration was different:it roughly indicated two peaks in May and September respectively,and a valley in July.（2）The spatial distribution of different atmospheric pollutant concentrations showed some differences.The spatial distributions of AQI,PM2.5 and PM10 were similar,showing a gradually increasing trend from southeast to northwest,with the maximum area located in Xuzhou,with values of 101.1（AQI）,65.1μg/m3(PM2.5)and 118.4μg/m3(PM10),respectively.The spatial distribution of NO2 concentration is exactly the opposite of O3.The spatial distribution values of NO2 showed obvious north-south difference.It investigated that the values in Southern Jiangsu（40.7μg/m3）was larger than that of Northern Jiangsu（30.2μg/m3）,the high value areas were in Nanjing（47.3μg/m3）and Changzhou（44.8μg/m3）,which happened to be the lowest value centers of O3,where there the O3 concentration was 63.1μg/m3 and 53.7μg/m3respectively.The spatial distribution of O3 concentration showed high value area in the north and low in the south,that was 69.3μg/m3 in Northen Jiangsu and 61.9μg/m3 in Southern Jiangsu,and the highest was in Yancheng（75.3μg/m3）,which was the lowest value center of NO2（23.8μg/m3）.The CO concentration in the north of Jiangsu province showed obvious east-west difference,which was higher in the west than that in the east.（3）There was a significant correlation between Jiangsu AQI and each pollutant,air pollution was closely related to meteorological factors.From the relationship between AQI and the primary pollutants,the correlations between AQI,PM2.5 and PM10 were the largest,and the correlation coefficient can reach above 0.96,showing that the PM2.5 and PM10 contributed the most to AQI.The SO2,NO2 and CO were significantly positively correlated with AQI,and the correlation coefficient was above 0.82.However,there was a significant negative correlation between O3 and AQI with the value being-0.67.For the relationship between air pollutants and meteorological elements,it investigated that air pollution was closely related to meteorological conditions such as air temperature,average air pressure,precipitation and sunshine hours.From December to February,the AQI,PM2.5 and PM10 in Jiangsu province were significantly correlated with the average temperature,but NO2,SO2 and CO were significantly negatively correlated with average temperature in December and January.From December to February,AQI,PM2.5,PM10 and NO2 in Jiangsu province were negatively correlated with the maximum precipitation,the O3 had a significant positive correlation with sunshine hours and maximum precipitation,almost opposite to that of AQI,PM2.5,PM10 and NO2.From December to January,the AQI,PM2.5,PM10,NO2,SO2 and CO were significantly negatively correlated with the average air pressure,and significantly positively correlated with the average air pressure in February.（4）On the basis of statistical analysis,the statistical equation was established,and combined with the regional climate model RegCM4,the statistical prediction method was used to predict the meteorological elements and air pollution in the winter of 2020 in Jiangsu province.The results showed that in the winter of 2020,the temperature of Jiangsu province presenteds an increasing distribution from northwest to southeast,and the numerical ranges of maximum temperature,average temperature and minimum temperature were 7～13℃,3～9℃and-3～5℃,respectively.The spatial distribution of daily precipitation was higher in the south and lower in the north,he values ranged from 0 mm to 8mm.The simulated maximum temperature,average temperature and daily precipitation were good concord with the predicted results of IPCC（Intergovernmental Panel on Climate Change）AR5（Fifth Assessment Report）in spatial distribution and numerical variation range,except the simulated minimum temperature was slightly high.Substituted into the statistical equations,the estimated pollutants concentrations in the winter of 2020 were close to that of the observed data in 2019,with little changes in AQI,PM2.5,PM10,NO2,CO and O3.While the simulated SO2 showed that the predicted value was higher than that of observed in 2019,with the mean value being 10.71 μg/m3.（5）Based on the anthropogenic aerosol emission inventory of the winter from 2014 to2018,the RegCM-CHEM4 was applied to analyze the anthropogenic aerosol direct radiation forcing and its regional climate effect in Jiangsu province in 2014-2018 winter.The results showed that the spatial distribution of surface emission flux and dry precipitation concentration of sulphate aerosol in winter was consistent,and the Southern Jiangsu was generally higher than that of in the Northern Jiangsu.The spatial distribution of short-wave radiative forcing was consistent with AOD（Aerosol Optical Depth）and a trend of gradual decline from west to east,the mean value of surface short-wave radiative forcing in winter was-15.6 W·m-2.The direct climatic effect of aerosol made the temperature droped wholy in the winter of Jiangsu,and the temperature reduction range reached 0.4～0.5℃.The winter sunshine hours generally decreased and the reduction range reached 0.0～0.4 h.In Huaian and Yancheng,the decrease of sunshine hours was greater than that in other areas.The direct climatic effect of aerosol led to the change of precipitation in Jiangsu province,showing larger in the east and less in the west.The precipitation in Suqian,Huaian,Yangzhou and Nanjing decreased by the value of about0.01～0.05 mm·d-1.The precipitation in Yancheng,Nantong,Suzhou,Wuxi and Changzhou increased by about 0.01～0.03 mm·d-1.Among them,the precipitation in Suqian showed a decreased high-value center(-0.05 mm·d-1),while in Yancheng had an increased high-value center(0.03 mm·d-1).Warming has also changed the activity of sulphate aerosols in Jiangsu province for a long time.Based on RegCM-CHEM4,in order to highlight the temperature change,the changes of the dry deposition rate,dry deposition flux and dry deposition concentration of sulfate aerosols with a warming of 0.9℃by 2050 were studied.The simulation analysis showed that,with the temperature increasing by 0.9℃to 2050,the dry deposition rate increased as a whole,with the values range from 0 to 0.05 mm·s-1.In terms of spatial distribution,the dry deposition flux of sulfate aerosol increased in southern Jiangsu with an increasing range of 0.03～0.05 mg·m-2·h-1,and it suggested a decreasing trend in northern Jiangsu.In addition,the dry deposition concentration of sulphate aerosols in Jiangsu province was generally reduced by about 1～7 ppb.Among them,there were two low-value centers for the change of dry deposition concentration,that were Xuzhou and Nantong,respectively,and the reduction range was up to 5～7 ppb.While the dry deposition concentration showed an increasing trend in Naning,with an increasing range of 1～2 ppb. |
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