Study On The Climate Effect Of Future Emissions Of BC Aerosols And Their Sensitivities Over China

Black carbon(BC)aerosol is formed in the combustion process of carbonaceous substances.As an important component of carbonaceous aerosols,it has a strong absorption of solar radiation in the visible to infrared range and can affect the radiation balance,and in turn has an impact on the climate.In China,there's a large amount of BC emissions and the condition has attracted wide public attention.In this paper,the regional environmental system integration model RIEMS2.0 and the latest 2020 and 2030 predicted BC emission list provided by Prof.Wang Qingeng are used to simulate the distribution and climatic effects of BC.For further study of the BC climate effects of different trades,there are four main anthropogenic emissions which contain industry,thermal power,transportation,and residential use.In order to better describe the monthly changes in BC emissions,the RIEMS 2.0 emission source reading module was optimized to read in monthly average BC emission source data.BC concentration and climate effects are simulated using the optimized model and seasonal differences are focused on.This paper uses the regional climate model RIEMS 2.0 and combines the scenarios of China's black carbon emissions in 2020 and 2030 to simulate the black carbon concentration and climate effects in China in 2020 and 2030.The results are showing as follows:(1)BC emissions in 2020 and 2030 are significantly reduced.The total BC emissions in China are 618.25 and 299.25 Gg/year respectively.The spatial distribution of emissions is similar to that of 2010.The major emission areas are located in North China,Central China,and Sichuan Basin area.The spatial distribution of average surface concentration in BC year is not uniform,and the largest value area is located from the south of Beijing to Hebei province.Compared with 2010,the BC concentration in North China,southern Jiangsu,eastern Hubei,and Sichuan Basin has decreased by about 4 ?g/m3.In 2030,the BC ground concentration further decreased,and the high concentration region was basically the same as that in 2020.In 2030,the surface concentration of BC in the Beijing-Tianjin-Hebei,Shandong Province,northern Shanxi,and northern Henan decreased by 1 ?g/m3 compared with 2020.(2)In 2020,North China,Sichuan Basin,and Gansu Province are areas with large BC radiative forcing.The spatial distribution of radiative forcing in 2030 is similar to that of 2020.From 2010 to 2030,the radiative forcing at the top of the atmosphere and the column radiative forcing decreased in most areas of China,and the ground radiative forcing decreased.The radiative forcing varies greatly in different seasons.The values of direct radiative forcing are the largest in winter,followed by spring and autumn,and the summer values are the smallest.(3)The temperature changes caused by BC in most parts of central and eastern China showed a positive change in 2010.The largest warming centers were in western Anhui,southern Henan,Sichuan Basin and southeastern Yunnan.The Bohai Sea and Yellow Sea areas in the east also experienced a warming of 0.04?0.12K.In 2020,the warming effect is still increasing in the middle and lower reaches of the Yangtze River and in Guizhou and other places.The temperature in the offshore waters off the Shandong peninsula has increased from 0.04 to 0.08 K.In 2030,the southeastern part of Sichuan Province experienced a strong temperature increase of about 0.24 K.The temperature rises in the east waters of Shandong and Jiangsu Provinces by 0.08 K However in the area east of Zhejiang,there is a temperature drop of 0?-0.04K.The emission sources data of industrial,thermal power,transportation,and residential were used for simulation respectively to analyze the radiative effects and climate effects of BC emissions from various industries in 2020.It can be obtained that:in 2020,the residential ues is the industry with the largest emission amount of BC in the four industries,followed by industry and transportation.The trade with the smallest total BC emissions is the thermal power industry.Considering the regional average BC surface concentration and column concentration formed by different industries,industry contributed the most,followed by industry and transportation,and the thermal power industry contributed the least.The distribution of temperature caused by BC in the four industries and the distribution of BC radiative forcing do not fully exhibit a corresponding linear relationship.The range of temperature change caused by BC in summer is much larger than that in winter,and the spatial distribution of temperature changes in summer is relatively more complicated.In summer China is affected by the monsoon and active small-scale convective system activities.It is difficult for BC to travel a long distance and easy to settle through the wet-clearing process.More warming-up effects occur on land and the effect is more complicated.There is a weak warming in most parts of China in winter caused by BC of different industries,especially in the central and eastern regions.The effect of this warming has been spreading eastwards due to the influence of the westerlies in winter.The four types of anthropogenic BC-emissions industries have all caused negative precipitation changes in the area north of the Yangtze River,while in the south of the Yangtze River,there has been an increase in precipitation.In order to describe the monthly changes in BC emission intensity,we modified the RIEMS 2.0 model to read the monthly data to initialize the current month's emissions,and use the improved model to simulate the climate effect of BC in 2020 again.The seasonal differences in BC radiative forcing and climate effects were analyzed.The analysis found that,for different seasons,the ground concentration in most areas during the spring and winter seasons is overestimated.But it is obviously underestimated in the eastern part of Qinghai province in summer and in northeast of China in autumn due to the open burning of straw.In the four seasons,the top radiative forcing of the atmosphere varied widely in the entire simulation region,ranging from 0 to 1.1 W/m2 in spring.The radiative forcing in the northern China,Northeast China,and Sichuan was greater.In summer,the top radiative forcing range was 0?1.5 W/m2.The radiative forcing is up to 1.454 W/m2 due to burning of open straw in the eastern part of Qinghai Province;The SRF ranges from 0 to 0.8 W/m2 in autumn with high values in the north and northeastern regions of China.In winter the range of SRF is 0?1.6 W/m2.In summer,BC has a general warming effect in the middle and lower reaches of the Yangtze River,North China,Northeast China,and the Sichuan Basin.Central China has cooled down.The large-value center for warming in autumn is located in the north of Anhui Province to Henan Province and radiates to Shandong,Shanxi,and other places with a temperature increase of more than 0.1K.In winter,BC has a general warming effect on the entire eastern part of China,but the warming rate is relatively small.After read in monthly emission sources,in summer BC resulted in a reduction in precipitation above-0.8 mm/day to the north of the Yangtze River and there's an increase in precipitation of 0.8 mm/day to south of the Yangtze River.While in Shandong,northern Shanxi,and Beijing Nearby there is a high value area with reduced precipitation.This result is consistent with the impact on the drought in the south of China as cited in other studies.