不同空间分辨率下印度特大城市上空AOD和Dongström指数（$α)$）的季节趋势
Seasonal trend of AOD and Ångström exponent($α)$ over Indian megacities in varying spatial resolution
摘要：
气溶胶光学特性、气溶胶光学厚度和气溶胶光学指数常被用来评价环境气溶胶负荷。气溶胶光学深度是通过散射和吸收引起的入射太阳辐射的完全消光来间接测量大气气溶胶含量的方法，而朗格斯特伦指数（$α)$）用于定性了解气溶胶颗粒大小。通过对长期时间序列气溶胶光学厚度资料的分析，揭示了特定地区气溶胶光学厚度随时间的变化规律。类似的研究，以longström指数（$α)$）给出了一个想法，如何颗粒尺寸分布变化在一些地区。这些研究不能仅仅依靠地面观测站的观测数据来进行，因为地面观测站的数量在地球上是不够的，而且大多数地方也没有相当长时期的观测数据。为了克服这一点，许多作者使用了Aqua和Terra卫星上的MODIS仪器探测到的辐射数据。在这项研究中，13年的MODIS 2级数据的Terra已被分析为四个印度大城市，即德里，孟买，加尔各答和钦奈使用著名的曼肯德尔统计和森的非参数估计的斜率。
英文摘要：
Aerosol optical characteristics AOD and Ångström exponent is often used to asses environmental aerosol loading. AOD or Aerosol Optical Depth is an indirect measure of atmospheric aerosol loading by means of total extinction of incoming solar radiation due to scattering and absorption whereas Ångström exponent($α)$ is used to get qualitative understanding of aerosol particle size. Analysis of long term time series AOD data reveals how AOD vis-à-vis aerosol on a particular place changes over time. Similar study with Ångström exponent($α)$ gives an idea how particle size distribution is changing over some area. Such studies cannot be conducted by data measured by ground based stations alone because they are inadequate in numbers on earth moreover such data for considerably long period are not available for most places. To overcome this, radiance data sensed by MODIS instruments on board Aqua and Terra satellite have been used by many authors. In this study 13 years of MODIS level 2 data by Terra have been analyzed for four Indian mega-cities namely Delhi, Mumbai, Kolkata and Chennai using well known Mann-Kendall statistics and Sen's non-parametric estimation of slopes.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
