Remote sensing and analysis of 2nd order, Arctic-aerosol parameters

气溶胶通常被定义为大气颗粒，其大小从一微米的一小部分到几十微米不等。它们源于多种气溶胶排放过程：森林大火、风沙、气体到颗粒的转化、火山喷发和海浪过程是一些主要的自然气溶胶来源，而城市和工业过程产生的化石燃料燃烧是最重要的人为来源。至少就其光学效应而言，气溶胶可大致分为双模、细模和粗模(半径大致为亚微米和超微米)。*未来五年，我们将继续研究双模参数的特征，例如细模和粗模的光学厚度(该参数基本上与气溶胶的柱状浓度成正比)和细模和粗模的有效半径(平均柱状半径)作为气溶胶种类的函数。在DG应用的背景下，拟议的研究将集中在从表面和柱状光学仪器中提取高风险的折射率信息(包括作为气溶胶散射特性的重要驱动因素的实部和作为气溶胶吸收特性的主要驱动力的复杂部分)。这些活动将细分为三个研究项目：(I)为期两年的博士后研究，从表面光谱测量中提取折射率的实部和复数部分，以及根据微物理和物种形成表面测量得出的光学性质。(2)由一名博士生牵头的光学反演分析，对PDF项目的精细模式折射率结果的表面到柱面传播进行分析；(3)由第二名博士生牵头的并行粗模分析(与第一名博士生密切合作)。*北极的遥感研究在社会效益方面特别重要，因为众所周知，北极地区会放大气候变化的影响(如政府间气候变化专门委员会最新报告所述)。气溶胶由于其直接(散射和吸收)效应和间接(气雾云相互作用)效应，是气候变化动力学中不确定性的最大来源(同上)。更好地了解气溶胶光学物理参数，特别是平均尺寸和折射率等密集参数，将有助于校准和改进北极-气溶胶模式的气溶胶动力学程序包，并相应地在北极的辐射强迫和气候模式方面产生重要后果。

Aerosols are commonly defined as atmospheric particles whose size ranges from a small fraction of a micrometer to tens of micrometers. They originate from a large variety of aerosol emission processes : forest fires, wind-blown deserts, gas to particle conversion, volcanic eruptions and ocean wave processes are some of the major natural aerosol sources while fossil fuel combustion due to urban and industrial processes is the most important anthropogenic source. Aerosols can, at least as far as their optical effects are concerned, be largely divided into bi-modal, fine and coarse mode components (roughly sub and super micrometer in radius).****Over the next five years, we will continue to pursue research into the characterization of bi-modal parameters such as fine and coarse mode aerosol optical depth (a parameter which is basically proportional to the column concentration of aerosols) and fine and coarse mode effective radius (average columnar radius) as a function of aerosol species. The proposed research within the context of this DG application will be focused on the higher risk extraction of refractive index information (both the real part which is an important driver of aerosol scattering properties and complex parts which is the major driver of aerosol absorption properties) from both surface and columnar optical instruments. These activities are will be subdivided into three research projects : (i) a 2-year postdoc led study on the retrieval of real and complex parts of the refractive index from surface spectral measurements and optical properties deduced from microphysical and speciation surface measurements. (ii) an optical retrieval analysis, led by a PhD student, of surface to column propagation of the fine mode refractive index findings of the pdf project (iii) a parallel coarse mode analysis (in close collaboration with the first PhD student) led by a second PhD student.****Remote sensing research in the Arctic is particularly relevant in a social benefit context since this region is known to magnify climate change effects (as described in the most recent IPCC report for example). Aerosols, by virtue of their direct (scattering and absorption) effects and indirect (aerosol cloud interaction) effects are the greatest source of uncertainty in climate change dynamics (ibid). A better understanding of aerosol opto-physical parameters, notably intensive parameters such as average size and refractive index will help to calibrate and improve the aerosol dynamics packages of Arctic-aerosol models and accordingly lead to important consequences in terms of radiative forcing and climate models of the Arctic.******