Document Type

Article

Publication Date

2015

Publication Title

Geophysical Research Abstracts

Volume

17

Pages

EGU2015-4675

Conference Name

EGU General Assembly 2015, April 13-17, 2015, Vienna, Austria

Abstract

Ethane (C₂H₆) has a large impact on tropospheric composition and air quality because of its involvement in the global VOC (volatile organic compound) – HOx – NOx chemistry responsible for generating and destroying tropospheric ozone. By acting as a major sink for tropospheric OH radicals, the abundance of C₂H₆ influences the atmospheric content of carbon monoxide and impacts the lifetime of methane. Moreover, it is an important source of PAN, a thermally unstable reservoir for NOx radicals.

On a global scale, the main sources of C₂H₆ are leakage from the production, transport of natural gas loss, biofuel consumption and biomass burning, mainly located in the Northern Hemisphere. Due to its relatively long lifetime of approximately two months, C₂H₆ is a sensitive indicator of tropospheric pollution and transport.

Using an optimized retrieval strategy (see Franco et al., 2014), we present here a 20-year long-term time series of C₂H₆ column abundance retrieved from ground-based Fourier Transform InfraRed (FTIR) solar spectra recorded from 1994 onwards at the high-altitude station of Jungfraujoch (Swiss Alps, 46.5° N, 3580 m a.s.l.), part of the Network for the Detection of Atmospheric Composition Change (NDACC, see http://www.ndacc.org). After a regular 1994 – 2008 decrease of the C₂H₆ amounts, which is very consistent with prior major studies (e.g., Aydin et al., 2011; Simpson et al., 2012) and our understanding of global C₂H₆ emissions, trend analysis using a bootstrap resampling tool reveals a C₂H₆ upturn and a statistically-significant sharp burden increase from 2009 onwards (Franco et al., 2014).

We hypothesize that this observed recent increase in C₂H₆ could affect the whole Northern Hemisphere and may be related to the recent massive growth in the exploitation of shale gas and tight oil reservoirs. This hypothesis is supported by measurements derived from solar occultation observations performed since 2004 by the Atmospheric Chemistry Experiment – Fourier Transform Spectrometer (ACE-FTS) instrument and at other NDACC sites, namely Toronto (44° N) and Thule (77° N). Indeed, the recent rates of changes characterizing these data sets are consistent in magnitude and sign with the one derived from the FTIR measurements at Jungfraujoch. In contrast, the ethane time series form Lauder (45° S) shows a monotonic decrease over the last two decades. Investigating both the cause and impact on air quality of the C₂H₆ upturn should be a high priority for the atmospheric chemistry community.

Rights

© The Authors 2015.

Published under the terms of a Creative Commons Attribution 3.0 Unported (CC BY 3.0) License.

Comments

An unpublished conference/abstract.

Original Publication Citation

Franco, B., Bader, W., Bovy, B., Mahieu, E., Fischer, E. V., Strong, K., Conway, S., Hannigan, J. W., Nussbaumer, E., Bernath, P. F., Boone, C. D., & Walker, K. A. (2015). Recent increase of ethane detected in the remote atmosphere of the Northern Hemisphere [Abstract]. EGU General Assembly 2015, Vienna, Austria. https://orbi.uliege.be/handle/2268/180485

ORCID

0000-0002-1255-396X (Bernath)

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