Greenhouse gas measurements from a UK network of tall towers: technical description and first results

Abstract

Abstract. A network of three tall tower measurement stations was set up in 2012 across the United Kingdom to expand measurements made at the long-term background northern hemispheric site, Mace Head, Ireland. Reliable and precise in situ greenhouse gas (GHG) analysis systems were developed and deployed at three sites in the UK with automated instrumentation measuring a suite of GHGs. The UK Deriving Emissions linked to Climate Change (UK DECC) network uses tall (165–230 m) open-lattice telecommunications towers, which provide a convenient platform for boundary layer trace gas sampling. In this paper we describe the automated measurement system and first results from the UK DECC network for CO2, CH4, N2O, SF6, CO and H2. CO2 and CH4 are measured at all of the UK DECC sites by cavity ring-down spectroscopy (CRDS) with multiple inlet heights at two of the three tall tower sites to assess for boundary layer stratification. The short-term precisions (1σ on 1 min means) of CRDS measurements at background mole fractions for January 2012 to September 2015 is < 0.05 µmol mol−1 for CO2 and < 0.3 nmol mol−1 for CH4. Repeatability of standard injections (1σ) is < 0.03 µmol mol−1 for CO2 and < 0.3 nmol mol−1 for CH4 for the same time period. N2O and SF6 are measured at three of the sites, and CO and H2 measurements are made at two of the sites, from a single inlet height using gas chromatography (GC) with an electron capture detector (ECD), flame ionisation detector (FID) or reduction gas analyser (RGA). Repeatability of individual injections (1σ) on GC and RGA instruments between January 2012 and September 2015 for CH4, N2O, SF6, CO and H2 measurements were < 2.8 nmol mol−1, < 0.4 nmol mol−1, < 0.07 pmol mol−1, < 2 nmol mol−1 and < 3 nmol mol−1, respectively. Instrumentation in the network is fully automated and includes sensors for measuring a variety of instrumental parameters such as flow, pressures, and sampling temperatures. Automated alerts are generated and emailed to site operators when instrumental parameters are not within defined set ranges. Automated instrument shutdowns occur for critical errors such as carrier gas flow rate deviations. Results from the network give good spatial and temporal coverage of atmospheric mixing ratios within the UK since early 2012. Results also show that all measured GHGs are increasing in mole fraction over the selected reporting period and, except for SF6, exhibit a seasonal trend. CO2 and CH4 also show strong diurnal cycles, with night-time maxima and daytime minima in mole fractions.

Quantifying the UK's carbon dioxide flux: an atmospheric inverse modelling approach using a regional measurement network

“…1 for the location of the sites). Four of these sites originally formed the UK-DECC network and are described in Stanley et al (2018), whilst two were developed under the GAUGE programme and are described in Stavert et al (2018). The site at Mace Head, Republic of Ireland, is a coastal, 10 m a.g.l.…”

“…The Climate Change Act 2008 (UK government, 2008) commits the UK to 80 % cuts in GHG emissions, from 1990 levels, by 2050. To support this legislation, a continuous and automated measurement network has been established Stavert et al, 2018) with the goal of providing estimates of GHG emissions using methods that are complementary to those used to compile the UK's bottom-up emissions inventory, reported annually to the United Nations Framework Convention on Climate Change (UNFCCC). Previous studies have used data from the UK Deriving Emissions related to Climate Change (UK-DECC) network to infer emissions of methane, nitrous oxide and HFC-134a from the UK Ganesan et al, 2015;Say et al, 2016).…”

Perfluorocyclobutane (PFC-318, <i>c</i>-C<sub>4</sub>F<sub>8</sub>) in the global atmosphere

“…Nevertheless, 10 cases of enhanced c-C 4 F 8 mole fractions were observed with the arrival of air masses from Eurasia. To trace the origin of these events, we used 3-hourly 50 d backward simulations for a passive tracer with version 10 of the Lagrangian particle dispersion model FLEXPART (Stohl et al, 2005). The model was driven with operational meteorological analyses of the European Centre for Medium Range Weather Forecasts (ECMWF, https://www.ecmwf.int/, last access: 10 February 2019).…”

Bayesian spatiotemporal inference of trace gas emissions using an integrated nested Laplacian approximation and Gaussian Markov random fields

“…The case studies observations from four measurement sites, three in the UK and one in Ireland, which are part of the UK Deriving Emissions related to Climate Change (DECC) network (Stanley et al, 2018). Figure 2 shows the location of these 1.2).…”