Ground-based remote sensing for the detection of greenhouse gases by Fourier transform infrared spectrometry: optimization of retrieval strategies and its validation

Tesis presentada en la Universidad de La Laguna para optar al Grado de Doctor en FísicaThe work is based on the high-quality ground-based remote sensing Fourier Transform InfraRed spectrometer for the inversion of precise total column amounts and vertical profiles of different atmospheric trace gases. The thesis is focused on the optimization of the retrieval strategies for the greenhouse gases water vapour and methane. For this purpose the inversion code PROFFIT is applied. The vertical distribution of water vapour and tropospheric methane as derived from our remote sensing measurements are compared against very precise in-situ measurements. Thus, the quality of our retrieved products are documented. These studies have been carry out at the Izaña Atmospheric Research Center (IARC-AEMET), Canary Island, 28.30 N, 16.50 W

Quality assessment of ozone total column amounts as monitored by ground-based solar absorption spectrometry in the near infrared (> 3000 cm−1)

This study examines the possibility of ground-based remote-sensing ozone total column amounts (OTC) from spectral signatures at 3040 and 4030 cm−1. These spectral regions are routinely measured by the NDACC (Network for the Detection of Atmospheric Composition Change) ground-based FTIR (Fourier transform infraRed) experiments. In addition, they are potentially detectable by the TCCON (Total Carbon Column Observing Network) FTIR instruments. The ozone retrieval strategy presented here estimates the OTC from NDACC FTIR high-resolution spectra with a theoretical precision of about 2 and 5% in the 3040 and 4030 cm−1 regions, respectively. Empirically, these OTC products are validated by inter-comparison to FTIR OTC reference retrievals in the 1000 cm−1 spectral region (standard reference for NDACC ozone products), using an 8-year FTIR time series (2005–2012) taken at the subtropical ozone supersite of the Izaña Atmospheric Observatory (Tenerife, Spain). Associated with the weaker ozone signatures at the higher wave number regions, the 3040 and 4030 cm−1 retrievals show lower vertical sensitivity than the 1000 cm−1 retrievals.The research leading to these results has received funding from the European Community’s Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 284421 (NORS project) and from the Ministerio de Economía and Competitividad from Spain for the project CGL2012-37505 (NOVIA project). M. Schneider and Y. González are supported by the European Research Council under the European Community’s Seventh Framework Programme (FP7/2007-2013)/ERC Grant agreement no. 256961 and E. Sepúlveda is supported by the NOVIA Project

Investigating the long-term evolution of subtropical ozone profiles applying ground-based FTIR spectrometry

This study investigates the long-term evolution of subtropical ozone profile time series (1999–2010) obtained from ground-based FTIR (Fourier Transform InfraRed) spectrometry at the Izaña Observatory ozone super-site. Different ozone retrieval strategies are examined, analysing the influence of an additional temperature retrieval and different constraints. The theoretical assessment reveals that the FTIR system is able to resolve four independent ozone layers with a precision of better than 6% in the troposphere and of better than 3% in the lower, middle and upper stratosphere. This total error includes the smoothing error, which dominates the random error budget. Furthermore, we estimate that the measurement noise as well as uncertainties in the applied atmospheric temperature profiles and instrumental line shape are leading error sources. We show that a simultaneous temperature retrieval can significantly reduce the total random errors and that a regular determination of the instrumental line shape is important for producing a consistent long-term dataset. These theoretical precision estimates are empirically confirmed by daily intercomparisons with Electro Chemical Cell (ECC) sonde profiles. In order to empirically document the long-term stability of the FTIR ozone profile data we compare the linear trends and seasonal cycles as obtained from the FTIR and ECC time series. Concerning seasonality, in winter both techniques observe stratospheric ozone profiles that are typical middle latitude profiles (low tropopause, low ozone maximum concentrations) and in summer/autumn profiles that are typical tropical profiles (high tropopause, high maximum concentrations). The linear trends estimated from the FTIR and the ECC datasets agree within their error bars. For the FTIR time series, we observe a significant negative trend in the upper troposphere/lower stratosphere of about −0.2%yr−1 and a significant positive trend in the middle and upper stratosphere of about +0.3%yr−1 and +0.4%yr−1, respectively. Identifying such small trends is a difficult task for any measurement technique. In this context, super-sites applying different techniques are very important for the detection of reliable ozone trends

First tropospheric δD data observed by ground-and space-based remote sensing and surface in-situ measurement techniques at MUSICA’s principle reference station (Izaña Observatory, Spain)

Póster presentado en: European Geosciences Union General Assembly celebrada del 7 al 12 de abril de 2013 en Viena.MUSICA is funded by the European Research Council under the European Community's Seventh Framework Programme (FP7/2007-2013) / ERC Grant agreement n 256961

Investigating the long-term evolution of subtropical ozone profiles applying ground-based FTIR spectrometry

This study investigates the long-term evolution of subtropical ozone profile time series (1999–2010) obtained from ground-based FTIR (Fourier Transform InfraRed) spectrometry at the Izaña Observatory ozone super-site. Different ozone retrieval strategies are examined, analysing the influence of an additional temperature retrieval and different constraints. The theoretical assessment reveals that the FTIR system is able to resolve four independent ozone layers with a precision of better than 6% in the troposphere and of better than 3% in the lower, middle and upper stratosphere. This total error includes the smoothing error, which dominates the random error budget.The research leading to these results has received funding from the European Community’s Seventh Framework Program ([FP7/2007- 2013]) under grant agreement no. 284421 (see Article II. 30. of the Grant Agreement). M. Schneider is supported by the European Research Council under the European Community’s Seventh Framework Program (FP7/2007-2013)/ERC Grant agreement no. 256961 and E. Sepúlveda enjoys a pre-doctoral fellowship from the Spanish Ministry of Education

Total carbon column observing network (TCCON) activities at Izaña, Tenerife (28º N, 17º W) [Póster]

Póster presentado en: 37th Annual European Meeting on Atmospheric Studies by Optical Methods celebrado del 23 al 26 de agosto de 2010 en Valladolid

CO2 total column amounts at the TCCON sites Izaña (28.3 N, 16.5 W) and Karlsruhe (49.1 N, 8.5 E)

Póster presentado en: International Radiation Symposium, celebrado del 6 al 10 de agosto de 2012 en Berlín, Alemania

The global and multi-annual MUSICA IASI {H2O, δD} pair dataset

We present a global and multi-annual space-borne dataset of tropospheric {H2O, δD} pairs that is based on radiance measurements from the nadir thermal infrared sensor IASI (Infrared Atmospheric Sounding Interferometer) on board the Metop satellites of EUMETSAT (European Organisation for the Exploitation of Meteorological Satellites). This dataset is an a posteriori processed extension of the MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) IASI full product dataset as presented in Schneider et al. (2021b). From the independently retrieved H2O and δD proxy states, their a priori settings and constraints, and their error covariances provided by the IASI full product dataset, we generate an optimal estimation product for pairs of H2O and δD. Here, this standard MUSICA method for deriving {H2O, δD} pairs is extended using an a posteriori reduction of the constraints for improving the retrieval sensitivity at dry conditions.This research has been supported by the Deutsche Forschungsgemeinschaft (grant no. 290612604, project MOTIV and grant no. 416767181, project TEDDY), the European Research Council, FP7 Ideas: European Research Council (MUSICA, grant no. 256961), the Bundesministerium für Bildung und Forschung (ForHLR supercomputer), the Ministerium für Wissenschaft, Forschung und Kunst Baden-Württemberg (ForHLR supercomputer), and the Ministerio de Economía y Competitividad (grant no. CGL2016-80688-P, project INMENSE)

CO2 total column amounts at TCCON sites Izana (28.3 N, 16.5 W) and Karlsruhe (49.1 N, 8.5 E)

The Total Carbon Observing Network (TCCON) is a global network of ground-based Fourier Transform Spectrometers recording direct solar spectra in the near-infrared (NIR) spectral region. Accurate and precise columnaveraged abundances of different greenhouse gases (GHGs) are retrieved, which are used for carbon cycle research [1] and for satellite validation (e.g. SCIAMACHY, GOSAT, OCOII). Official TCCON data are generated using the GFIT code compared FTIR retrieval results with in-situ measurements developed at NASA/JPL [2]. In this study, we compare FTIR retrieval results with in-situ measurements as well as the GFIT code with the radiative transfer and retrieval algorithm PROFFIT [3]

The MUSICA IASI {H2_{2}O, δD} pair product

We present a global and multi-annual space-borne dataset of tropospheric {H$_{2}$O, δD} pairs that is based on radiance measurements from the nadir thermal infrared sensor IASI (Infrared Atmospheric Sounding Interferometer) onboard the Metop satellites of EUMETSAT (European Organisation for the Exploitation of Meteorological Satellites). This dataset is an a posteriori processed extension of the MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) IASI full product dataset as presented in Schneider et al. (2021b). From the independently retrieved H$_{2}$O and δD proxy states, their a priori settings and constraints, and their error covariances provided by the IASI full product dataset we generate an optimal estimation product for pairs of H$_{2}$O and δD. Here, this standard MUSICA method for deriving {H$_{2}$O, δD} pairs is extended using an a posteriori reduction of the constraints for improving the retrieval sensitivity at dry conditions. By applying this improved water isotopologue post-processing for all cloud-free MUSICA IASI retrievals, this yields a {H$_{2}$O, δD} pair dataset for the whole period from October 2014 to June 2019 with a global coverage twice per day (local morning and evening overpass times). In total, the dataset covers more than 1200 million individually processed observations. The retrievals are most sensitivity to variations of {H$_{2}$O, δD} pairs within the free troposphere, with up to 30 % of all retrievals containing vertical profile information in the {H$_{2}$O, δD} pair product. After applying appropriate quality filters, the largest number of reliable pair data arises for tropical and subtropical summer regions, but also for higher latitudes there is a considerable amount of reliable data. Exemplary time-series over the Tropical Atlantic and West Africa are chosen to illustrates the potential of the MUSICA IASI {H$_{2}$O, δD} pair data for atmospheric moisture pathway studiess. Finally, the dataset is referenced with the DOI 10.35097/415 (Diekmann et al., 2021)