Advanced constituent retrieval algorithms for composition and aerosol measurement and instrument development

关于对流层上层臭氧和大气气溶胶在地球辐射平衡中的作用的有限知识是气候变化背后驱动因素的两个最大不确定因素。臭氧和气溶胶的全球分布必须通过太空遥测来确定。然而，地面遥测测量仍然是改进测量方法和新仪器发展的重要参考。地面观测--气溶胶的AERONET和柱臭氧的Dobson和Breyer网络以及臭氧垂直剖面的臭氧探空仪--为空间测量提供了粗略的空间分布和参考数据。 臭氧的平流层轮廓测量是通过许多不同的技术进行的，包括测量肢体散射太阳辐照度、掩星测量和太阳后向散射测量。从紫外线到近红外的光谱分辨率测量可以提供有关大气成分的信息和关于气溶胶颗粒特性的数据。 申请者在加拿大环境部开发了两种不同的二极管阵列光谱仪。首先，一种名为太阳光谱仪(SPS)的小型手持仪器被建造成与加拿大宇航员史蒂夫·麦克莱恩一起在航天飞机上飞行，这是他的第一次太空飞行。该仪器发现它的科学定位安装在NASA ER-2高空飞机的翼舱中，在那里它被用来测量臭氧层柱和进行太阳辐射测量。在测量入射太阳辐射的同时，还进行了散射太阳辐射和最低点辐射的肢体扫描。极限点和最低点的测量是在两个极化平面上进行的，可以用于气溶胶粒子的测量。ER-2还携带了先进的现场颗粒计数器，对这两个数据集的分析和比较可以证明这种方法在从空间进行气溶胶特性测量方面的性能。一名理科硕士。将支持学生使用最先进的分析工具重新分析广泛的(约125次飞行)数据集，从而开发出用于地面和太空的新仪器。 申请者拥有一套广泛的MAESTRO(通过掩星反演的平流层和对流层气溶胶消光测量)和在特内里费岛伊扎纳收集的SPS数据，这些数据是与AERONET校准工作一起进行的。Maestro和SPS收集的全光谱范围数据(~300-1000 nm)可以作为一个很好的模型，用来确定与AERONET太阳光度计相比，分光光度计是否提供了更好的数据集。太阳光度计是一种滤光式仪器，波段数量有限，存在长期稳定性问题，在紫外线下的性能很差。M.Sc.对该数据集的分析。学生可能会回答这个问题，并导致在操作网络中用于成分和气溶胶测量的商业仪器。 大气化学卫星上的MAESTRO分光光度计现在已经收集了8年的数据。运营分析是由一套过时的代码完成的，应该用更准确和更当代的代码来取代。这项工作是由之前的一名博士生完成的，他证明了全球光谱和高度拟合算法可以提高反演的性能，但代码还没有翻译成操作系统，也没有得到充分的验证。拟议支持一名博士后研究员帮助建立申请人的新实验室，与研究生合作，并带头开发先进的全球拟合检索算法。这将提高反演的成功率，扩大采样的海拔范围，并允许与臭氧和二氧化氮等其他吸收体的温度和水蒸气剖面一起同时反演。

Limited knowledge about the role of upper tropospheric ozone and atmospheric aerosol in the Earth's radiation balance are the two largest uncertainties of the drivers behind climate change. The global distribution of ozone and aerosol must be determined by remote sounding from space. However, ground-based remote-sounding measurements remain important references in the development of improved measurement methodologies and new instruments. The ground-based observations - AERONET for aerosol and the Dobson and Brewer networks in the case of column ozone and ozonesondes for vertical profiling of ozone - provide crude spatial distributions and reference data for space measurements. Stratospheric profile measurements of ozone are made by a number of different techniques including measurements of limb-scattered solar irradiance, occultation measurements and solar backscatter measurements. Spectrally resolved measurements from the UV to the near IR can provide information about atmospheric constituents and data about aerosol particle properties. The applicant developed two different diode array spectrometers at Environment Canada. One, a small handheld instrument called the SunPhotoSpectrometer (SPS) was constructed to fly on the Space Shuttle with Canadian astronaut Steve MacLean on his first space flight. The instrument found its scientific niche mounted in a wing pod on the NASA ER-2 high-altitude aircraft where it was used to measure ozone column and make solar radiation measurements. Limb scans of scattered solar radiation and nadir radiances were made along with a measurement of the incident solar radiation. The limb and nadir measurements were made in two polarization planes and can be used to make aerosol particle measurements. The ER-2 also carried sophisticated in situ particle counters and the analysis and comparison of these two data sets can demonstrate the performance of this approach for making aerosol property measurements from space. One M.Sc. student will be supported to re-analyze the extensive (~125 flights) data sets using state-of-the-art analysis tools leading to teh development of new instruments for use on the ground and in space. The applicant has an extensive set of MAESTRO (Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation) and SPS data collected at Izana, Tenerife which were made in conjunction with an AERONET calibration exercise. The full spectral range data (~300-1000nm) collected by the MAESTRO and SPS can serve as a good model for determining whether spectrophotometers provide an improved data set compared to AERONET sunphotometers. The sunphotometers are filter instruments with a limited number of bands, long-term stability issues and poor performance in the ultraviolet. The analysis of this dataset by a M.Sc. student may answer that question and lead to a commercial instrument for composition and aerosol measurement in an operational network. The MAESTRO spectrophotometer which is on the Atmospheric Chemistry Satellite has now collected 8 years of data. Operational analysis is being done by a dated set of codes that should be replaced with something more accurate and contemporary. Work was done by a previous Ph.D. student who demonstrated that a global spectral and altitude fitting algorithm could improve the performance of the retrievals, but the code has not been translated into an operational system nor sufficiently validated. It is proposed to support a post-doctoral fellow to help set up the applicant's new laboratory, work with the graduate students and spearhead the development of an advanced global fitting retrieval algorithm. This will increase the success rate of the retrievals, extend the altitude range sampled and allow the simultaneous retrieval of temperature and water vapour profiles along with those of other absorbers such as ozone and nitrogen dioxide.