Remote sensing of Arctic aerosols: analysis of intensive parameters

气溶胶是一种大气颗粒，其大小从一微米的一小部分（一米的百万分之一）到几十微米不等。它们在浓度上可以表现出很大的（广泛的）变化，在大小、形状和化学成分上可以表现出显著的（密集的）变化。地面太阳光度法是测量平均气溶胶效应的主要技术；一种是全天跟踪太阳，测量仪器和太阳之间的气溶胶造成的衰减。在污染事件中，气溶胶（特别是细的亚微米气溶胶）对健康有重大影响。它们对辐射和云特性的影响是重要的气候变化因素。北极地区的气候变化比南方地区更为严重，气溶胶在促成这些变化方面发挥了重要作用。因此，重要的是要充分了解气溶胶，特别是北极气溶胶的物理性质。

Aerosols are atmospheric particles whose size ranges from a small fraction of a micrometer (1/ 1000000 of a meter) to tens of micrometers. They can exhibit large (extensive) variations in concentration and significant (intensive) variations in their size, shape and chemical composition. Ground-based sunphotometry is the predominant technique for measuring average aerosol effects; one tracks the sun all day and measures the attenuation caused by the aerosols between the instrument and the sun. Aerosols (notably fine, sub-micron aerosols) have significant health impacts during pollution events. Their effect on radiation as well as on cloud properties represent important climate change factors. Climatic changes in the Arctic are more severe than in southern regions and aerosols play a major role in contributing to these changes. It is accordingly important that the physical properties of aerosols and Arctic aerosols in particular be well understood. My long term objective is to better understand aerosol behavior in terms of measurable optical variations. The significance, for example, of some specific aerosol optical depth (AOD) spectral shape, a change in the angular variation of sky radiance, or variations in lidar (pulsed laser) measurements of aerosol altitude properties, cannot be understood until one has a grasp of the essential environmental and instrumental physics influencing the measurement. This objective is advantageously accompanied by projects involving the evaluation of aerosol dynamics models using optical data; our experience has been that the process of model evaluation inevitably enhances one's physical understanding of both the aerosol phenomena which the model purports to simulate and the measurements themselves. The short term objective of the research proposal is to better understand the measurable physics of second order (intensive) aerosol optical parameters. This specifically means the employment of spectral techniques to extract fine and coarse mode effective radius values and the extraction of single scattering albedo (sensitive to aerosol absorption).