Methane mole fraction and δ13C above and below the trade wind inversion at Ascension Island in air sampled by aerial robotics

Brownlow, R., Lowry, D., Thomas, R. M., Fisher, R. E., France, J. L., Cain, M., Richardson, T. S., Greatwood, C., Freer, J., Pyle, J. A., Mackenzie, A. R. and Nisbet, E. G. (2016) Methane mole fraction and δ13C above and below the trade wind inversion at Ascension Island in air sampled by aerial robotics. Geophysical Research Letters, 43 (22). 11893–11902. ISSN 0094-8276

[img]
Preview
PDF (Brownlow_et_al-2016-Geophysical_Research_Letters) - Submitted Version
Download (1MB) | Preview

Abstract

Ascension Island is a remote South Atlantic equatorial site, ideal for monitoring tropical background CH4. In September 2014 and July 2015, octocopters were used to collect air samples in Tedlar bags from different heights above and below the well-defined Trade Wind Inversion (TWI), sampling a maximum altitude of 2700 m above mean sea level. Sampling captured both remote air in the marine boundary layer below the TWI and also air masses above the TWI that had been lofted by convective systems in the African tropics. Air above the TWI was characterized by higher CH4, but no distinct shift in δ13C was observed compared to the air below. Back trajectories indicate that lofted CH4 emissions from Southern Hemisphere Africa have bulk δ13CCH4 signatures similar to background, suggesting mixed emissions from wetlands, agriculture, and biomass burning. The campaigns illustrate the usefulness of unmanned aerial system sampling and Ascension's value for atmospheric measurement in an understudied region.

Item Type: Article
Additional Information: ©2016. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Faculty \ School: Faculty of Science > School of Environmental Sciences
Related URLs:
Depositing User: Pure Connector
Date Deposited: 23 Nov 2016 15:00
Last Modified: 04 May 2020 23:54
URI: https://ueaeprints.uea.ac.uk/id/eprint/61485
DOI: 10.1002/2016GL071155

Actions (login required)

View Item View Item