Retrieval of Atmospheric Parameters from Spectroscopic Observations using DOAS Instruments - RAPSODI

使用 DOAS 仪器从光谱观测中检索大气参数 - RAPSODI

• 批准号: 272342164
• 负责人: Professor Dr. Ulrich Platt
• 金额: --
• 依托单位: Institut für Umweltphysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/272342164?language=en
• 关键词: Retrieval; Atmospheric; Parameters; Spectroscopic; Observations

The Earth s atmosphere is governed by complex chemical and dynamical processes, and a detailed knowledge of the vertical distribution of trace gases and aerosols is crucial for a thorough understanding of the atmospheric system. Remote sensing measurements are ideally suited for the determination of the vertical structure of the atmosphere. Ground-based, airborne and satellite borne remote sensing measurements provide a contact free method to measure the atmospheric composition from a distance. In particular, Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) represents versatile and cost effective method for the observation of the vertical distribution of a variety of trace gases and of aerosols. In the framework of the proposed project, a novel retrieval algorithm will be developed, which will allow for a thorough exploitation of the information contained in MAX-DOAS measurements of scattered and direct sunlight. In contrast to existing algorithms, DOAS analysis and profile retrieval will be performed in a single step. This simultaneous retrieval of vertical profiles of aerosols and trace gases directly from the measured spectral radiances is expected to lead to a significant increase in the overall information content. Additional information on the state of the atmosphere will be gained from a simulation of the broadband spectral structure, which has so far been ignored in traditional DOAS applications, and from an explicit modelling of rotational Raman scattering (Ring effect). A T-Matrix and/or Mie model coupled to a radiative transfer model will allow for a retrieval of aerosol microphysical properties, such as size distribution and complex refractive index, from solar almucantar measurements, similar to existing algorithms for Aeronet sun photometer measurements. This algorithm will serve as the basis for a thorough assessment of the overall information content of MAX-DOAS measurements with respect to trace gases, aerosol extinction and aerosol microphysical properties. Measurements by a novel Polarimetric MAX-DOAS (PMAX-DOAS) instrument, which will be designed and built in the scope of this project, will yield a further enhancement of the information content of scattered light measurements. Skylight measurements at different orientations of a rotatable polarising filter will allow for the reconstruction of the Stokes vector. Polarisation-dependent measurements of the intensity, trace gas column and Ring effect will significantly increase the accuracy of aerosol and trace gas retrievals. In order to fully exploit information content of the PMAX-DOAS, the retrieval algorithm will be based on a vectorised radiative transfer model, which enables the simulation of the full Stokes vector.

地球的大气由复杂的化学和动力学过程控制，对痕量气体和气溶胶的垂直分布的详细知识对于对大气系统的透彻了解至关重要。遥感测量值非常适合确定大气的垂直结构。地面，机载和卫星传播遥感测量值提供了一种无触点的方法，可以从远处测量大气组成。特别是，多轴差异光吸收光谱（MAX-DOAS）代表了观察各种痕量气体和气溶胶的垂直分布的通用和成本效益方法。在拟议项目的框架内，将开发出一种新型的检索算法，这将允许对散射和直射阳光的Max-Doas测量中包含的信息进行彻底的开发。与现有算法相反，DOAS分析和配置文件检索将在一个步骤中进行。直接从测得的光谱辐射中直接检索气溶胶和痕量气体的垂直轮廓，预计将导致整体信息含量显着增加。关于大气状态的其他信息将从宽带光谱结构的模拟中获得，该结构在传统的DOAS应用中被忽略，以及旋转拉曼散射的明确建模（环效应）。与辐射转移模型相连的T-Matrix和/或MIE模型将允许从太阳能Almucantar测量值中检索气溶胶微物理特性，例如尺寸分布和复杂的折射率，类似于Aeronet SunoNet SunoNet Sunephotemphote Meturemess的现有算法。该算法将作为对痕量气体，气溶胶灭绝和气溶胶微物理特性的最大值测量的总体信息含量进行彻底评估的基础。通过在该项目范围内设计和构建的新型极化最大值（PMAX-DOAS）仪器的测量将进一步增强散射光测量的信息含量。可旋转偏振过滤器的不同方向下的天窗测量将允许重建Stokes向量。强度，痕量气柱和环效应的极化依赖性测量将显着提高气溶胶和痕量气体检索的准确性。为了完全利用PMAX-DOAS的信息内容，检索算法将基于矢量辐射传输模型，该模型可以模拟完整的Stokes向量。