High accuracy line intensities for carbon dioxide
Lead Research Organisation:
University College London
Department Name: Physics and Astronomy
Abstract
All CO2 remote sensing activity, from both the ground and space, relies on monitoring how CO2 absorbs light. All this monitoring is therefore heavily dependent on understanding the absorption properties of the CO2 molecule which is usually obtained by measurements performed in the laboratory. In particular the accurate knowledge of the strength of individual absorption lines is crucial to determining how much CO2 is present and allowing the atmospheric data to be interpreted. Without high accuracy values for line intensities, reliable CO2 retrievals are simply not possible. Particularly with their emphasis on variation of CO2 concentrations with time, current missions and proposed missions require CO2 line intensities to be determined to significantly better than 1% accuracy if they are to fulfill their stated goals: intensities accurate to better than 0.5% are really required. Current line intensities measured in the laboratory simply do not gives this level of accuracy: most are accurate to about 5% with a few high quality measurements being good to 1 - 3%. Hence current cO2 retrievals values are limited by the available laboratory data. The aim of this proposal is to provide an accurate theoretical solution to the problem of CO2 line intensities based on the application of high accuracy, first principles quantum mechanical calculations for the intensities and experimental data for the line positions. The resulting new lists of CO2 transition intensities will be made widely available and, in particular, used to inform atmospheric databases which are used for the majority of atmospheric applications of molecular spectroscopy.
Planned Impact
This is potentially a high impact project. The major impact will be for the atmospheric remote sensing community as the project will allow them to significantly improve CO2 retrievals with the consequence improvement in CO2 monitoring, modeling and. hopefully, control. The improvement in CO2 line intensities proposed here is essential to properly exploit actual or planned missions and programmes aimed explicitly at recording CO2 concentrations in the Earth's atmosphere.
Accurate CO2 data is important for a whole variety of other applications including planetary atmospheres (Mars, Venus, Exoplanets) and elsewhere in the Universe. It will also contribute to projects on space craft re-entry and other applications of CO2 data which will certainly appear during the course of the project.
The line intensities (and associated line list) generated in this project will be distributed widely and vigorously to maximise its potential impact. It will be made available via (atmospheric) databases HITRAN and GEISA; via BADC and via
web portals such as the Virtual Atomic and Molecular Data Centre (VAMDC), and my own exomol.com website.
My work on molecular spectroscopy regularly gets extensive national and international press coverage. I use topics from this work (including ones relating to atmospheric physics) as the basis of popular talks which I give to schools and other non-specialist groups.
Accurate CO2 data is important for a whole variety of other applications including planetary atmospheres (Mars, Venus, Exoplanets) and elsewhere in the Universe. It will also contribute to projects on space craft re-entry and other applications of CO2 data which will certainly appear during the course of the project.
The line intensities (and associated line list) generated in this project will be distributed widely and vigorously to maximise its potential impact. It will be made available via (atmospheric) databases HITRAN and GEISA; via BADC and via
web portals such as the Virtual Atomic and Molecular Data Centre (VAMDC), and my own exomol.com website.
My work on molecular spectroscopy regularly gets extensive national and international press coverage. I use topics from this work (including ones relating to atmospheric physics) as the basis of popular talks which I give to schools and other non-specialist groups.
Publications
Tennyson J
(2016)
The ExoMol database: Molecular line lists for exoplanet and other hot atmospheres
in Journal of Molecular Spectroscopy
Zak E
(2016)
A room temperature CO2 line list with ab initio computed intensities
in Journal of Quantitative Spectroscopy and Radiative Transfer
Birk M
(2017)
Accurate line intensities for water transitions in the infrared: Comparison of theory and experiment
in Journal of Quantitative Spectroscopy and Radiative Transfer
Zak E
(2017)
Room temperature line lists for CO2 symmetric isotopologues with ab initio computed intensities
in Journal of Quantitative Spectroscopy and Radiative Transfer
Gamache R
(2017)
Total internal partition sums for 166 isotopologues of 51 molecules important in planetary atmospheres: Application to HITRAN2016 and beyond
in Journal of Quantitative Spectroscopy and Radiative Transfer
Rothman L
(2013)
The HITRAN2012 molecular spectroscopic database
in Journal of Quantitative Spectroscopy and Radiative Transfer
Zak E
(2017)
Room temperature linelists for CO2 asymmetric isotopologues with ab initio computed intensities
in Journal of Quantitative Spectroscopy and Radiative Transfer
Hill C
(2013)
A new relational database structure and online interface for the HITRAN database
in Journal of Quantitative Spectroscopy and Radiative Transfer
Kyuberis A
(2017)
Room temperature line lists for deuterated water
in Journal of Quantitative Spectroscopy and Radiative Transfer
Rutkowski L
(2018)
An experimental water line list at 1950 K in the 6250-6670 cm - 1 region
in Journal of Quantitative Spectroscopy and Radiative Transfer
Description | We have developed a very accurate theoretical model for how much light one molecule of CO2 absorbs. The results of this are now being adopted by various databases and remote sensing experiments. |
Exploitation Route | We will contribute our data to databases such as HITRAN and GEISA |
Sectors | Environment |
Description | Very accurate quantum mechanical calculations have been performed giving much better data on how carbon dioxide absorbs light. Our data have been adopted by major players in atmospheric analysis of CO2 such as OCO-2 and have been included in their entirety in the recent HITRAN upgrade |
First Year Of Impact | 2014 |
Sector | Environment,Other |
Title | Databases of molecular line lists |
Description | Our molecular line lists have been collected as data. These are distributed directly from our own website and via other data centres (Strasbourg, BADC) and via other databases: HITRAN, GEISA, KIDA, BASECOL, HITEMP etc |
Type Of Material | Database/Collection of data |
Provided To Others? | Yes |
Impact | HITRAN has 200,000 users. Our data is now central to this. Other data is having an important influence in other key areas eg Exoplanet research. |
Description | HITRAN database |
Organisation | Harvard University |
Department | Harvard-Smithsonian Center for Astrophysics |
Country | United States |
Sector | Academic/University |
PI Contribution | The HITRAN database is run from the Harvard-Smithson Center for Astrophysics, USA. We are major contributors to the database. |
Collaborator Contribution | They evaluate data and include it in the database. |
Impact | The HITRAN database is a common output plus associated publication every 4 years. |
Description | schools talks |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Schools |
Results and Impact | I have regularly been invited back to schools who wish to increase A-level participation in STEM subjects have regularly been invited back to schools who wish to increase A-level participation in STEM subjects |
Year(s) Of Engagement Activity | Pre-2006,2006,2007,2008,2009,2010,2011,2012,2013,2014 |