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Efficient radiative transfer calculation and sensor performance requirements for the aerosol retrieval by airborne imaging spectroscopy


Seidel, F; Schläpfer, D; Itten, K I (2009). Efficient radiative transfer calculation and sensor performance requirements for the aerosol retrieval by airborne imaging spectroscopy. In: 6th EARSeL Imaging Spectroscopy SIG workshop: proceedings , Tel Aviv, Israel, 16 March 2009 - 19 March 2009, online.

Abstract

Detailed aerosol measurements in time and space are crucial to address open questions in climate research. Earth observation is a key instrument for that matter but it is biased by large uncertainties. Using airborne imaging spectroscopy, such as ESA's upcoming airborne Earth observing instrument APEX, allows determining the widely used aerosol optical depth (AOD) with unprecedented accuracy
thanks to its high spatial and spectral resolution, optimal calibration and high signal-to-noise ratios (SNR).
This study was carried out within the overall aim of developing such a tropospheric aerosol retrieval
algorithm. Basic and efficient radiative transfer equations were applied to determine the sensor performance
requirement and a sensitivity analysis in context of the aerosol retrieval. The AOD retrieval sensitivity requirement was chosen according to the demands of atmospheric correction processes. Therefore, a novel parameterization of the diffuse path-radiance was developed to simulate the atmospheric and surface effects on the signal at the sensor level. It was found for typical remote sensing conditions and a surface albedo of less than 30% that a SNR of circa 300 is sufficient to meet the AOD retrieval sensitivity requirement at 550nm. A surface albedo
around 50% requires much more SNR, which makes the AOD retrieval very difficult. The retrieval performance is further analyzed throughout the visual spectral range for a changing solar geometry and different aerosol characteristics. As expected, the blue spectral region above dark surfaces and high aerosol loadings will provide the most accurate retrieval results. In general, the AOD
retrieval feasibility could be proven for the analyzed cases for APEX under realistic simulated conditions.

Abstract

Detailed aerosol measurements in time and space are crucial to address open questions in climate research. Earth observation is a key instrument for that matter but it is biased by large uncertainties. Using airborne imaging spectroscopy, such as ESA's upcoming airborne Earth observing instrument APEX, allows determining the widely used aerosol optical depth (AOD) with unprecedented accuracy
thanks to its high spatial and spectral resolution, optimal calibration and high signal-to-noise ratios (SNR).
This study was carried out within the overall aim of developing such a tropospheric aerosol retrieval
algorithm. Basic and efficient radiative transfer equations were applied to determine the sensor performance
requirement and a sensitivity analysis in context of the aerosol retrieval. The AOD retrieval sensitivity requirement was chosen according to the demands of atmospheric correction processes. Therefore, a novel parameterization of the diffuse path-radiance was developed to simulate the atmospheric and surface effects on the signal at the sensor level. It was found for typical remote sensing conditions and a surface albedo of less than 30% that a SNR of circa 300 is sufficient to meet the AOD retrieval sensitivity requirement at 550nm. A surface albedo
around 50% requires much more SNR, which makes the AOD retrieval very difficult. The retrieval performance is further analyzed throughout the visual spectral range for a changing solar geometry and different aerosol characteristics. As expected, the blue spectral region above dark surfaces and high aerosol loadings will provide the most accurate retrieval results. In general, the AOD
retrieval feasibility could be proven for the analyzed cases for APEX under realistic simulated conditions.

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Additional indexing

Item Type:Conference or Workshop Item (Paper), not refereed, original work
Communities & Collections:07 Faculty of Science > Institute of Geography
Dewey Decimal Classification:910 Geography & travel
Language:English
Event End Date:19 March 2009
Deposited On:24 Nov 2009 09:18
Last Modified:05 Apr 2016 13:34
Publisher:European Association of Remote Sensing Laboratories
Official URL:http://www.earsel6th.tau.ac.il/Programme.html

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