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|Title:||A first analysis of the atmospheric measurements from TANSO/GOSAT|
|Author:||Teixeira, Bárbara Sofia Santos|
|Publisher:||Faculdade de Ciências e Tecnologia|
|Abstract:||This work examines the atmospheric spectra recorded by the TANSO-FTS instrument onboard the GOSAT platform, with the aim of assessing the usefulness of these measurements for chemistry applications, and in particular for monitoring reactive nitrogen compounds in the low atmosphere. As a dedicated mission for climate, GOSAT has a series of advantages over other sounders, such as high spectral resolution and extensive coverage of thermal infrared and shortwave infrared spectral regions. In the first part of our work, we determine, by performing a set of radiative transfer calculations, the molecular bands which compose the TANSO-FTS spectra in the different spectral regions, and the species which could potentially be detected under high pollution condition. We show in particular that N2O and NH3 have absorption signatures in the SWIR band number 2, which could possibly be used – further work is needed for a definitive assessment – to improve on source monitoring. In the second part of this work, we concentrate on the thermal infrared measurements of TANSO-FTS and provide a comparative study with the validated and well-studied radiance measurements performed by the IASI instrument onboard MetOP. Through an inter-comparison over the oceans with strict criteria of co-localization and temporal matching, we show the TANSO-FTS radiances to be biased high by 2 K as compared to IASI for day-time measurements, while for night-time TANSO-FTS radiances to be biased low by 0.7 K as compared to IASI. We also find that the theoretical line shape is not perfectly adapted for reproducing the measurements. These are issues that need attention for more sophisticated analysis with GOSAT. Still, relying on a simple radiance indexing method and brightness temperature difference calculations, we were able show that the TANSO-FTS has considerable detection capabilities of NH3, apparently by far superior to those of IASI. The instrument is shown to make unambiguous detection of hotspots on a daily basis and to enable capturing seasonal variations in all months, including in winter when the NH3 concentration are weakest.|
|Description:||Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau em Mestre em Engenharia Física|
|Appears in Collections:||FCT: DF - Dissertações de Mestrado|
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