Fundamental understanding of reactive nitrogen in the global upper troposphere

Project Information

UpTrop

Grant agreement ID: 851854

DOI

10.3030/851854

Project closed

EC signature date 12 September 2019

Start date 1 December 2019

End date 30 November 2025

Funded under

• EXCELLENT SCIENCE - European Research Council (ERC)

Total cost

€ 1 490 036,25

EU contribution

€ 1 490 036,25

Coordinated by

UNIVERSITY COLLEGE LONDON
United Kingdom

Periodic Reporting for period 4 - UpTrop (Fundamental understanding of reactive nitrogen in the global upper troposphere)

Reporting period: 2023-08-01 to 2024-11-30

Summary of the context and overall objectives of the project

Glaring gaps in our understanding of the chemical composition and physical and chemical processes in the global upper troposphere impede our ability to reliably use satellite observations of atmospheric composition as constraints on air pollution and to determine the true influence of tropospheric ozone on global climate and changes in atmospheric oxidants on air quality and the persistence and climate impact of the potent greenhouse gas methane. Central to these knowledge gaps is the sources, processing and fate of a family of chemicals known as reactive nitrogen. These uncertainties persist due to the lack of routine reliable observations of this family of compounds in the remote upper troposphere.

Though the upper troposphere is far away (8-12 km overhead), it is an important contributor to the quality of the air we breathe and it also affects the formation and persistence of climate-altering greenhouse gases. Without a clear understanding of the processes occurring in the upper troposphere, we are unable to develop well-informed policies that improve air quality and curtail a climate emergency.

The overarching objective of UpTrop is to address gaps in observations and knowledge of the processes occurring in the upper troposphere and use this new knowledge to determine the true influence of the upper troposphere on Earth’s atmosphere. We will achieve this using innovative data derivation techniques, rigorous statistical methods, state-of-art models, and recently launched space-based instruments with unprecedented spatial resolution.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

A project website was established at the start of the project (https://maraisresearchgroup.co.uk/uptrop.html) to provide the public with details of team members and collaborators and to showcase research outputs, media coverage, and public engagement activities. Work carried out in the first half of the project has focused on generating new datasets, validating these with independent data, and interpreting the results with a state-of-science chemical transport model. Research findings have been presented by team members at 13 conferences and many invited seminars at leading institutions in the US (MIT, Harvard), the UK (UCL), Europe (KNMI), and Australia (University of Melbourne). Completed portions of UpTrop have so far been shared with the public in 2 public engagement pieces written in The Conversation and with the science community as 3 peer-reviewed papers in prominent journals. The latest of these publications on the environmental harm of rocket launches and re-entry heating of returning space junk and reusable components has received substantial media attention from leading agencies such as the BBC, The Guardian, Forbes, Vox, Al Jazeera, Channel 4, US NPR, US abc news, Australia ABC, Sky News, and many more (https://maraisresearchgroup.co.uk/media_coverage.html https://wiley.altmetric.com/details/129725006).

The datasets and software that have been generated as part of UpTrop are available for public access and use (Data: https://doi.org/10.5522/04/14586558 https://doi.org/10.5522/04/17032349; Software: https://doi.org/10.5281/zenodo.4058442). It is evident from the number of people who have viewed (854) and downloaded (661) these, that UpTrop is producing highly sought after resources.

The UpTrop team is currently using these new datasets to determine how large the errors are in our understanding of the chemical composition of the upper troposphere by comparison to a state-of-art chemical transport model. The discrepancies we are identifying between the model and UpTrop datasets is guiding our further steps to investigate the causes for these differences.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

UpTrop is enhancing understanding of the physical and chemical processes in the undersampled and underappreciated upper troposphere (8-12 km overhead). This is being achieved using innovative approaches to develop new observationally derived datasets from instruments in space and use historical and recent observations from commercial and NASA research aircraft observations. Key to this innovation is the use of the state-of-science chemical transport model GEOS-Chem to aid interpretation of UpTrop datasets and address knowledge gaps.

Expected results at the end of UpTrop include publicly available datasets of atmospheric composition in the global upper troposphere, renewed understanding of the sources and physical and chemical processes that determine atmospheric composition in the global upper troposphere, improved constraints on important atmospheric sources of reactive nitrogen such as lightning, and greater confidence in the role of the upper troposphere in influencing Earth’s climate and air quality.

New observations of nitrogen dioxide in the global upper troposphere obtained as part of UpTrop