Analyses of multi-species greenhouse gases and related tracers using novel measurements at Weybourne Atmospheric Observatory, Norfolk, UK

Fleming, Leigh (2023) Analyses of multi-species greenhouse gases and related tracers using novel measurements at Weybourne Atmospheric Observatory, Norfolk, UK. Doctoral thesis, University of East Anglia.

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Abstract

Carbon dioxide (CO2) is the most important greenhouse gas that influences anthropogenic climate change, yet a full understanding of the carbon cycle is still lacking. Measurement of CO2 alone provides a limited understanding of carbon cycle processes. Measurement of other gas species as ‘tracers’ provides additional information regarding carbon cycle processes. This thesis explores novel measurements of tracers, and novel methods for tracer applications for use in carbon cycle studies, using the Weybourne Atmospheric Observatory (WAO), UK, as a case study.

A ‘Picarro G2207-i' O2 analyser was tested in the laboratory and at WAO. The potential benefits of this analyser are reduction in calibration gas consumption and fewer drying requirements. The built-in water-correction procedure did not sufficiently correct for the influence of water vapour on the O2 mole fraction. A reference gas cylinder was required to reduce the influence of baseline drift. When measuring dry, ambient air, the G2207-i’s results showed an average difference from the established O2 analyser of 13.6±7.5 per meg. The overall performance was not quite as good as established analysers.

Radon-222 was used to derive monthly maritime ‘background’ concentrations for multiple atmospheric gases. These backgrounds were compared to those calculated from other methods. The radon-derived backgrounds displayed good agreement with other methods, with some variability depending on the processes involved in a species’ sources and sinks. The radon method appropriately filtered air masses which had recent interaction with terrestrial land masses.

Measurement of δ13C, δ18O and δ17O in CO2 using an Aerodyne TILDAS analyser were conducted at WAO, and used to calculate Δ17O. Two calibration methodologies were explored, with small differences between the results. The repeatability of the δ13C, δ17O and δ18O were all within the WMO goals; the Δ17O results were outside the goals, but in the context of ambient variability, still allow useful interpretation.

Item Type:	Thesis (Doctoral)
Faculty \ School:	Faculty of Science > School of Environmental Sciences
Depositing User:	Jennifer Whitaker
Date Deposited:	20 Feb 2024 13:09
Last Modified:	22 Feb 2024 13:04
URI:	https://ueaeprints.uea.ac.uk/id/eprint/94364
DOI:

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