中国东部气溶胶直接辐射效应与云参数反演研究

发布时间：2018-04-30 03:09

本文选题：中国东部 + 气溶胶直接辐射效应　；参考：《中国科学技术大学》2017年硕士论文

【摘要】：云和气溶胶是地气系统中的重要组成部分,对地气系统的辐射收支有重要作用。气溶胶通过直接和间接效应在地气系统的辐射收支、全球气候变化、大气稳定度和区域环境质量方面起着不容忽视的作用。云则是可以通过辐射、潜热和对流强迫三种机制影响气候并直接参与全球水循环。中国东部位于亚洲主要的季风区,气溶胶分布扩散、云和降水天气和气候等都会受到季风环流的影响。近几十年来,中国东部经济迅速发展,频繁的工业活动排放了大量的人为气溶胶,造成了严重的环境和气候问题。因此,研究中国东部地区云和气溶胶的时空分布特征以及气候效应对充分认识中国东部的气候特征具有重要的科学意义,同时对改善人类生存环境和制定正确的政府决策等也具有重要的社会意义。本文首先通过多年的地基和卫星气溶胶观测资料,揭示了中国东部气溶胶光学参数的时空分布特征。之后利用SBDART辐射传输模式,以地基和卫星气溶胶观测资料和再分析资料为输入,开展了中国东部格点尺度上的气溶胶直接辐射强迫的模拟研究。最后,利用葵花-8卫星观测资料,依据双光谱反射率算法,开展了云微物理参数的反演工作。本文的主要成果如下:(1)通过对2001-2014年MODIS气溶胶资料的分析,揭示了中国东部气溶胶光学厚度的时空分布特征从空间分布上看,东亚地区的气溶胶光学厚度(AOD)高值区位于中国东部、四川盆地和珠三角地区,低值区则主要集中在西北地区和东北地区。同时,春夏季节东亚地区的AOD高值区面积和强度都明显大于秋冬季节。从年际变化上看,东亚地区的AOD在冬季为明显的上升趋势,中国东部以及华北地区、长三角地区的AOD则是在四季均呈现上升趋势。从季节变化上看,东亚地区的AOD在春季为峰值,秋季为最低值,其余三个区域的AOD则是在夏季为最大值,冬季为最小值。(2)利用2001-2014年AERONET地基气溶胶观测资料,揭示了中国东部气溶胶单次散射反照率和不对称因子的时空分布特征北方地区的气溶胶单次散射反照率(SSA)和不对称因子(ASY)在夏季为最大值,冬季为最小值,且城市站点的SSA数值小于郊区站点。南方地区的气溶胶SSA在春季达到最大值,冬季为最小值,ASY则是夏季最大,秋季最小。SSA和ASY的季节变化明显,并且在5～8月份容易出现峰值。从年际变化上看,气溶胶SSA的年际变化比ASY显著,且夏季和秋季的年际变化比春季和冬季时显著。(3)基于气溶胶实测资料,开展辐射传输模式的模拟研究,阐明了中国东部格点尺度上气溶胶直接辐射强迫的时空分布特征选取中国东部秋季的典型污染过程和洁净过程进行研究,污染过程时中国东部的AOD均值和高值区面积都明显大于洁净过程。对两个过程的后向轨迹进行模拟发现,洁净过程时南北方地区气流来源相同,气溶胶性质统一,但是污染过程时的南北方气溶胶来源不同,气溶胶性质存在差异。对气溶胶直接辐射强迫(ADRF)进行模拟发现,ADRF的空间分布与AOD的空间分布模态基本相同,同时污染过程时的ADRF的强度和高值区面积都大于洁净过程。对2006—2014年中国东部冬夏季节的气溶胶光学参数进行统计发现,中国东部的气溶胶AOD、SSA、ASY都存在冬小夏大的季节变化特征。对ADRF进行模拟发现,大气顶和地面的ADRF均为负值,其中大气顶的ADRF数值为-20W/m_2～-45W/m_2,地面的ADRF数值为大气顶的四倍。AOD和ADRF的年际变化显著,且夏季的年际变化比冬季更明显。ADRF会造成地面层温度的降低和湿度的增加。另外,受到季风环流的影响,AOD和ADRF的空间分布在季风强弱年时存在明显差异。对于中国东部大部分地区来说,AOD在冬季风强年和夏季风弱年时数值更大,对应的ADRF的强度也更强。(4)利用葵花-8卫星观测资料,结合双光谱反射率算法,开展了云参数的反演研究工作1.6μm通道反射率对云相态和地表类型变化非常敏感,且0.64μm和1.6μm通道反射率对太阳和卫星天顶角的变化敏感,对相对方位角的变化不敏感。对2016年4月15日的个例进行反演,发现冰云主要分布于副热带陆面,0.64μm通道反射率在0.2～0.4之间,1.6μm通道反射率为0.1～0.2,红外亮温在220K～230K之间;混合云的分布范围最广,可见光反射率在0.2以上,1.6μm通道反射率为0.05～0.4,亮温在240K～270K之间;水云主要分布在洋面,0.64μm通道反射率在0.2以上,1.6μm通道反射率为0.1～0.3,亮温为273K～290K。对云参数反演结果进行简单分析,冰云的粒子半径(CER)大于水云,冰云的CER在10μm以上,水云的CER在10μm以下。冰云的光学厚度(COD)在15以上,部分冰云的COD达到了 50以上,水云的COD在10～20之间,但是在0.64μm通道反射率比较大的区域,水云COD在40以上。冰云的云水路径(CWP)数值大于水云,冰云的CWP数值基本在200g/m_2以上,但是大部分水云的CWP在100g/m_2以下。
[Abstract]:Cloud and aerosol are important parts of the earth gas system and play an important role in the radiation budget of the ground gas system. Through direct and indirect effects, aerosols play an important role in the radiation revenue and expenditure of the earth gas system, global climate change, atmospheric stability and regional environmental quality. Flow forcing three mechanisms to affect the climate and directly participate in the global water cycle. East China is located in the main monsoon region of Asia, aerosol distribution, cloud and precipitation weather and climate are affected by the monsoon circulation. In recent decades, the economy of eastern China has developed rapidly, and frequent industrial activities emit a large number of anthropogenic aerosols. It has become a serious environmental and climate problem. Therefore, it is of great scientific significance to study the spatial and temporal distribution characteristics of cloud and aerosol in eastern China and the climate effect to fully understand the climate characteristics of eastern China. At the same time, it also has important social significance for improving human living environment and making correct government decisions. The temporal and spatial distribution characteristics of aerosol optical parameters in eastern China are revealed through years of ground-based and satellite aerosol observations. Then the SBDART radiation transmission model is used to simulate the direct radiative forcing of aerosols on the grid point scale in eastern China with the input of ground and satellite aerosol observation data and reanalysis data. Finally, using the sunflower -8 satellite observation data, the inversion work of the cloud microphysical parameters is carried out based on the dual spectral reflectance algorithm. The main achievements of this paper are as follows: (1) the spatial and temporal distribution characteristics of the aerosol optical thickness in eastern China are revealed from the spatial distribution of East Asia by the analysis of the 2001-2014 year aerosol data. The high value area of aerosol optical thickness (AOD) is located in the east of China, the Sichuan basin and the Pearl River Delta region, and the low value area is mainly concentrated in the northwest and northeast regions. At the same time, the area and intensity of the high value area of AOD in East Asia in the spring and summer season are obviously larger than those in autumn and winter. From the interannual variation, the AOD in East Asia is obvious in winter. In the eastern and North China regions, the AOD of the Yangtze River Delta region has an upward trend in the four seasons. From the seasonal variation, the AOD in East Asia is the peak in spring, the autumn is the lowest, the AOD in the other three regions is the maximum in summer and the minimum in winter. (2) using the 2001-2014 year AERONET foundation Aerosol Observation The spatial and temporal distribution of single scattering albedo and asymmetric factors in eastern China was revealed. Aerosol single scattering albedo (SSA) and asymmetric factor (ASY) were the maximum in the northern region, and the winter was the minimum in winter, and the SSA value of urban sites was smaller than that in the suburban sites. The aerosol SSA in the South was reached in the spring. The maximum in winter is the minimum, ASY is the largest in summer, the minimum seasonal variation of.SSA and ASY in autumn is obvious, and the peak is easy to appear in 5~8 months. From the interannual variation, the annual variation of aerosol SSA is significantly higher than that of ASY, and the interannual variation in summer and autumn is more significant than that in spring and winter. (3) based on the measured data of aerosol, the radiant changes are carried out. The spatial and temporal distribution characteristics of direct aerosol radiation forced by aerosol on the eastern part of China are studied. The typical pollution process and clean process of eastern China in autumn are studied. The AOD mean and high value area of eastern China are obviously larger than the clean process in the process of pollution. The back direction of the two processes is backward. The trajectory simulation shows that the air flow in the South and the north is the same in the South and the north, and the aerosol properties are unified, but the sources of the aerosols are different and the aerosol properties are different during the pollution process. The simulation of the aerosol direct radiation forcing (ADRF) shows that the spatial distribution of the ADRF is basically the same as the spatial distribution mode of the AOD. The intensity and area of high value area of ADRF in the process of pollution are all larger than those of the clean process. The aerosol optical parameters of eastern China during the winter and summer season from 2006 to 2014 have been found. The aerosol AOD, SSA, and ASY in eastern China have the seasonal variation characteristics of the winter small summer, and the ADRF is found to be negative, the ADRF of the air top and the ground is negative, The ADRF value of the top of the atmosphere is -20W/m_2 to -45W/m_2, and the ADRF value of the ground is four times that of the top of the atmosphere, and the interannual variation of.AOD and ADRF is remarkable, and the interannual variation in summer is more obvious than that of the winter, which causes the decrease of the ground layer temperature and the increase of the humidity. In addition, the spatial distribution of AOD and ADRF in the monsoon is influenced by the monsoon circulation, and the spatial distribution of AOD and ADRF is strong and weak. There are obvious differences in the year. For most parts of eastern China, AOD has greater numerical value and stronger ADRF intensity in winter wind years and summer winds. (4) using the sunflower -8 satellite observation data and the double spectral reflectance algorithm, the reflectivity of the 1.6 M channel of the cloud parameters is carried out to the cloud state and the ground. The change of table type is very sensitive, and the reflectivity of 0.64 m and 1.6 mu m channels is sensitive to the change of the sun and the zenith angle of the satellite. It is insensitive to the change of relative azimuth. In the case of April 15, 2016, it is found that the ice clouds are mainly distributed in the subtropical land, the reflection rate of the 0.64 mu m channel is from 0.2 to 0.4, and the 1.6 M channel reflectivity is 0.1 to 0.. 2, the infrared brightness temperature is between 220K and 230K; the distribution range of the mixed cloud is the most extensive, the reflectance of the visible light is above 0.2, the reflectance of the 1.6 mu m channel is 0.05 ~ 0.4, the brightness temperature is between 240K and 270K; the water cloud is mainly distributed in the ocean surface, the 0.64 mu m channel reflectivity is above 0.2, the reverse ejection rate of the 1.6 M channel is 0.1 to 0.3, and the brightness temperature is 273K to 290K. inversion knot of the cloud parameters. A simple analysis shows that the particle radius (CER) of the ice cloud is greater than that of the water cloud, the CER of the ice cloud is above 10 mu m, the CER of the water cloud is below 10 mu m. The optical thickness of the ice cloud (COD) is above 15, the COD of some ice clouds is over 50, the COD of the water cloud is 10~20, but the water cloud COD is above 40 in the area of the 0.64 Muu reflectivity, and the cloud COD is above 40. Ice clouds. The cloud water path (CWP) is larger than the water cloud. The CWP value of the ice cloud is basically above 200g/m_2, but the CWP of most water clouds is below 100g/m_2.

【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X513

【参考文献】