中国地区黑碳气溶胶的气候效应及其对粒径和光学参数的敏感性研究

发布时间：2017-12-26 21:42

本文关键词：中国地区黑碳气溶胶的气候效应及其对粒径和光学参数的敏感性研究　出处：《南京大学》2017年硕士论文　论文类型：学位论文

【摘要】：黑碳气溶胶(BC)是由含碳的化石燃料和生物质等不完全燃烧产生的,它在气候系统中扮演着独特而重要的角色。BC能在可见光和红外波段高效地吸收太阳辐射,加热大气,影响气候和空气质量;它还可以通过作为云凝结核,改变云的反照率等影响大气环流。中国的BC排放较大,受到广泛的国际关注,本文利用RIEMS2.0模式模拟研究了中国地区BC的气候效应及其对排放源,粒径分布及光学系数的敏感性。本文利用最新的2006年以及2010年高分辨率排放源,研究了中国地区BC和总人为气溶胶的浓度分布特征、辐射效应以及对排放源的敏感性,结果表明:(1)与2006年相比,2010年BC的年均地面浓度在中国东部和中部地区主要是增长趋势,最大增值为10.90μg/m3,在中国东部地区光学厚度最大增加为0.006(2)2010年中东部地区平均的BC的云天大气顶辐射强迫为0.29W/m2,总气溶胶辐射强迫为-1.1W/m2。相比于2006年,2010年BC的辐射强迫在中国东部大部分地区增强,总气溶胶大气顶负辐射强迫在中国东部大部分地区呈减弱趋势。(3)与2006年相比,2010年BC在中国东部大部分地区使得地面气温上升的幅度增大,BC带来地面气温上升的幅度增加的最大值为0.30K。2006年总人为气溶胶引起的平均气温变化为-0.096K,最大变化-0.285K,而在2010年则分别为-0.063K和-0.256K。总体而言,排放源的变化使得人为气溶胶的降温效应减弱,其原因在于BC的增温效应增强和散射性气溶胶的降温效应减弱。基于最新的BC排放数据,在RIEMS2.0模式中提出了 BC的分粒径方案(BC粒子划分为四个模态,中值直径分别为0.15、0.41、0.96和5.4μm),通过与常数粒径方案的对比发现,分粒径方案能更好地模拟中国地区的BC。从区域平均值的角度来看,常数粒径方案和分粒径方案模拟的BC的差异表现为:分粒径方案模拟的BC地面直接辐射强迫减弱了 0.08～0.56 W/m2;BC的增温效应在华中地区和华北地区减弱了-0.04～-0.16 K。两种方案模拟的BC对降水的影响差异较大,在不同区域之间的差值变化范围为-2.4～3.2mm/d。广泛使用的常数粒径方案可能高估了 BC的浓度、直接辐射强迫和增温效应。分粒径方案模拟的BC主要集中在工业发达和人口密集的华北,长三角地区和四川盆地地区。BC在华东和华北地区的地面浓度变化范围为1～8μg/m3。BC浓度的高值区出现在黄河和长江流域的下游地区以及四川盆地,最大值达到13.07μg/m3。BC的直接气候效应表现为:云天和晴空柱辐射强迫的区域平均值分别为1.27和1.39W/m2;云天和晴空地面辐射强迫的区域平均值分别为-0.84和-1.00 W/m2;中国大部分地区的地面气温增加,增温范围为0.04～0.24K;华南地区降水以减少为主,减小范围为-0.5～-2.5 mm/d;长江流域中下游地区,降水增加,增加的最大值达到3.35 mm/d。综合考虑BC的直接和间接气候效应时:正辐射强迫可达6W/m2;在华东和华北地区的大部分区域,增温显著,BC引起地面气温的变化范围为0.04～0.20K;华南和东北地区降水的增加较为明显,降水增加的区域平均值分别为0.08和0.13 mm/d。BC的光学参数依赖于它的粒径和复折射指数,利用Mie散射原理计算了不同尺度BC的光学参数,运用新的光学参数模拟BC的浓度分布、辐射强迫和气候效应,并与均一尺度光学参数的模拟结果进行了比较,分析光学参数对BC气候效应模拟的敏感性。与原来的均一化的光学参数化方案相比:根据分粒径重新计算的光学参数模拟的BC在第一模态的浓度明显增加,在其他几个模态下BC的浓度减小,总的BC浓度也是减小的。四种模态的BC和总BC的区域平均柱浓度变化分别为:0.085、-0.095、-0.089和-0.054 mg/m2。BC光学厚度的变化范围是-0.008～-0.0064,BC光学厚度变化的区域平均值为-0.0019。从区域平均的角度分析,BC的晴天辐射强迫减弱了 0.03 W/m2,云天辐射强迫增强了 0.06 W/m2;使用新的方案模拟的增温区域减少,增温值减小,模拟的降温效应在部分地区增强了,BC引起降温的变化范围为-0.04～-0.24K。运用分粒径光学参数的模拟结果显示:四种粒径的BC的区域平均地面浓度分别为0.372,、0.264、0.055和0.004μg/m3。第一和第二模态BC的地面浓度所占的比例分别为53%和38%。BC总地面浓度的区域平均值为0.69μg/m3,总柱浓度的区域平均值为0.28 mg/m2。在晴天和云天情况下,BC大气顶直接辐射强迫的区域平均值分别为0.49和0.36 W/m2。在华东,华北和华中的大部分地区,BC引起年均地面气温的上升,变化范围为0.05～0.15K;在华南地区,BC引起降温。在华东地区,华北地区,华南地区以及东北地区,BC均使得年均降水减少,区域平均变化值分别为:-0.83mm/d、-0.05mm/d、-0.11mm/d 和-0.13mm/d;在西部干旱半干旱地区,BC引起年均降水增加了 0.01 mm/d;冬季,BC引起较强的地面气温上升,在长江和黄河流域之间的地区,地面气温上升显著,最大增温达到0.42K;夏季,在中国南部的部分地区,BC引起降水增加;在长江流域部分地区,BC引起降水减少。BC引起的环流、气压以及温度的变化存在较好地对应关系。
[Abstract]:Black carbon aerosol (BC) is produced by incomplete combustion of carbon containing fossil fuels and biomass. It plays a unique and important role in the climate system. BC can effectively absorb solar radiation in the visible and infrared bands, heating the atmosphere, affecting the climate and air quality, and it can also affect the atmospheric circulation by changing the albedo of clouds and so on. China's BC emissions are relatively large, and it has attracted widespread international attention. In this paper, we use RIEMS2.0 model to simulate the climate effect of BC in China and its sensitivity to emission sources, particle size distribution and optical coefficient. Based on the latest 2006 and 2010 high resolution emission source, on the Chinese area of BC and total aerosol concentration distribution, radiation effect and the emission source sensitivity, results showed that: (1) compared with 2006, the annual ground concentration of BC in 2010 in the eastern and central regions of China are mainly growth trend. The maximum value is 10.90 g/m3, in the eastern region of the largest Chinese optical thickness increased to 0.006 (2) BC average in the eastern region in 2010 sky ADRF is 0.29W/m2, the total aerosol radiative forcing is -1.1W/m2. Compared with 2006, the radiation forcing of BC increased in most areas of eastern China in 2010, and the total aerosol top negative radiation forcing decreased in most parts of eastern China. (3) compared with 2006, BC increased the surface air temperature in most areas of eastern China in 2010. The maximum value of BC increased with 0.30K. The average temperature variation caused by total anthropogenic aerosol in 2006 was -0.096K, the maximum change was -0.285K, while in 2010, it was -0.063K and -0.256K respectively. In general, the cooling effect of artificial aerosols is weakened due to the change of emission sources. The reason is that the warming effect of BC is enhanced and the cooling effect of scattering aerosol is weakened. BC emissions based on the latest data, in RIEMS2.0 mode BC is proposed in the scheme (particle size BC particles are divided into four modes, median diameter were 0.15, 0.41, 0.96 and 5.4 m), compared with the constant size scheme that size scheme can better simulate the China area BC. The average value from the regional perspective, the difference scheme and Simulation of constant particle size and size of the BC scheme as follows: size BC ground simulation scheme of direct radiative forcing reduced 0.08 ~ 0.56 W/m2; warming effect of BC weakened -0.04 ~ -0.16 K in Central China region and North China region. The effects of the two schemes of BC on precipitation are different, and the range of difference between different regions is -2.4 to 3.2mm/d. The widely used constant particle size scheme may overestimate the concentration of BC, the direct radiation forcing and the warming effect. The BC is mainly concentrated in the developed and densely populated North China, the Yangtze River Delta region and the Sichuan basin area. The ground concentration variation of BC in East China and North China is 1~8 u g/m3. The high value area of BC concentration appeared in the lower reaches of the Yellow River and the Yangtze River Basin and the Sichuan basin, and the maximum value reached 13.07 mu g/m3. The direct climate effect of BC as follows: the sky and sky column radiative forcing of the regional average is 1.27 and 1.39W/m2 respectively; and the clear sky surface radiative forcing the regional average values were -0.84 and -1.00 W/m2; the ground temperature in most parts of Chinese increased warming range is 0.04 ~ 0.24K; the precipitation in Southern China region to reduce. Reduce the range of -0.5 to -2.5 mm/d; the middle and lower reaches of Yangtze River Basin in the precipitation increases, the maximum value of 3.35 mm/d increase. Considering the BC direct and indirect climate effect: positive radiative forcing is 6W/m2; most of the region in East and North China, significant warming, BC caused by changes in surface temperature range is 0.04 ~ 0.20K; Southern China and Northeast China precipitation increased obviously, the increase of precipitation, the regional average values were 0.08 and 0.13 mm/d. The optical parameters of BC depends on its particle size and complex refractive index, the optical parameters of different scales of BC were calculated by Mie scattering principle, the optical parameters of new BC simulation of concentration distribution, radiative forcing and climate effects, and simulation and optical parameters of uniform scale were compared to the results, the sensitivity analysis of parameters on the optical simulation BC climate effect. Compared with the original homogenization optical parameterization scheme, the concentration of BC simulated by the optical parameters calculated by particle size is obviously increased in the first mode, and in other modes, the concentration of BC decreases, and the total BC concentration decreases. The changes in the regional mean column concentration of the four modes of BC and the total BC were 0.085, -0.095, -0.089 and -0.054 mg/m2 respectively. The range of BC optical thickness varies from -0.008 to -0.0064, and the regional mean value of BC optical thickness changes is -0.0019. From the analysis of the regional average of sunny radiation BC forced reduced 0.03 W/m2, forcing the enhanced 0.06 W/m2 sky radiation; warming region using a new simulation scheme is reduced, increasing temperature decreased, the cooling effect simulation enhanced in some areas, BC change range of cooling is -0.04 ~ -0.24K. The simulation results of the optical parameters of the particle size show that the average ground concentration of the four BC sizes is 0.372, 0.264, 0.055 and 0.004 micron g/m3, respectively. The ratio of ground concentration to the first and second mode BC is 53% and 38%, respectively. The average area average of the total ground concentration of BC is 0.69 mu g/m3, and the regional average of the total column concentration is 0.28 mg/m2. In the sunny sky and under the condition of BC, the top of the atmosphere of direct radiative forcing the regional average values were 0.49 and 0.36 W/m2. In most areas of East China, North China and central China, BC causes the annual average ground temperature rise, which ranges from 0.05 to 0.15K; in Southern China, BC causes cooling. In eastern China, North China, Southern China and Northeast China, the average annual precipitation is reduced by BC, and the regional average changes are: -0.83mm
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X513

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