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 CO
CO
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 SF
Carbon dioxide (CO
Remote measurements of GHGs first started in the 1950s at the Mauna Loa Observatory, Hawaii, USA. Remote background locations were chosen as to avoid strong anthropogenic sources encountered at stations close to populated regions which made data interpretation more difficult at the time (Keeling et al., 1976; Popa et al., 2010). Other background stations followed in the decades after Mauna Loa was set up, such as at Baring Head, New Zealand, in 1970 (Brailsford et al., 2012) and the Atmospheric Life Experiment (ALE, a predecessor to the current Advanced Global Atmospheric Gases Experiment, AGAGE) in 1978 (Prinn et al., 2000). Measurements from these background stations only constrained estimations of global or hemispheric-scale fluxes within inverse models and were not able to capture local to regional scales (Gloor et al., 2001). Tall tower measurements in conjunction with transport models were proposed as a means to estimate local to regional-scale GHG fluxes (Tans, 1993). GHG measurements from tall towers began in the 1990s (Haszpra et al., 2001; Popa et al., 2010) and have been expanded in the 2000s as part of a number of national and international measurement campaigns (Vermeulen, 2007; Kozlova et al., 2008; Thompson et al., 2009; Popa et al., 2010). Measurements made from ground level at terrestrial sites often display complex atmospheric signals with source and sink interactions visible. Sampling from tall towers reduces the influence of these local effects (Gerbig et al., 2003, 2009).
Greenhouse gas and ozone-depleting substance species and instrumentation at each UK DECC site.
For over 30 years, high-frequency measurements of GHGs have been made at
Mace Head (MHD), a global background measurement station on the west coast
of Ireland. MHD predominantly receives well-mixed air masses, which have
travelled across the northern Atlantic, in the prevailing south-westerly
winds, providing a good mid-latitude Northern Hemisphere background signal.
These in situ, high-frequency, high-precision measurements have been used to
estimate emissions of GHGs from the UK using the Inversion Technique for
Emission Modelling (InTEM) methodology (Manning et
al., 2011). In 2011, the UK government funded the establishment and
integration of three new tall tower measurements stations in the UK. The UK
Deriving Emissions linked to Climate Change (UK DECC) network was
established to monitor the atmospheric mole fractions of GHGs, improve the
spatial and temporal distribution of measurements across the UK and improve
GHG emission estimates for comparison with the national inventory; see
Manning et al. (2011) for more details. The new
network became operational in 2012. Of the four atmospheric monitoring
stations, two main stations (MHD and Tacolneston: TAC) measure a suite of
The main objective of this paper is to describe an automated, reliable and
high-precision analysis system for routine unattended monitoring of
atmospheric CO
Site names, locations and inlet heights.
The location of the three tall tower UK DECC stations was designed to provide good spatial measurement coverage across the UK utilising open-lattice tall towers. Good spatial coverage was necessary to provide information on emissions from the UK's devolved administrative regions of Scotland, Wales, England and Northern Ireland. The network consists of four sites all measuring key GHGs (Table 1). Instruments at the Irish coastal site at MHD take whole air samples from 10 m above ground level (m a.g.l.), whilst the three UK sites sample from differing heights on tall telecommunications towers (45–222 m a.g.l.). The site locations and descriptions are given in Fig. 1 and Table 2, respectively. Minor instrumental changes have occurred within the network lifetime; however, the described instrumentation at the sites is correct as of September 2015.
The MHD atmospheric research station is one of only a few western European
stations that for significant periods of time is representative of
mid-latitude northern hemispheric background air and provides an essential
baseline input for the UK DECC network. At the station (Fig. 1), numerous
ambient air measurements are made as part of the AGAGE (Cunnold et al.,
1997; Prinn et al., 2000), Integrated Carbon Observation System (ICOS; Vardag et al., 2014) and the Global Atmospheric
Watch (GAW) networks. Prevailing winds from the west to southwest sector
bring well-mixed background Atlantic air to the site on average 51 % of
the time (Jennings et al., 2003). Polluted European air masses, as well
as tropical maritime air masses, cross the site periodically. MHD is
uniquely positioned to observe these different air masses. Galway, the
closest city, has a population of
Location of UK DECC network stations, showing from north to south: TTA, Angus, UK; MHD, Mace Head, Ireland; TAC, Tacolneston, UK; and RGL, Ridge Hill, UK.
RGL is a rural UK site located 30 km east from the border of England and
Wales (Fig. 1). It is 16 km south-east of Hereford (population 55 800), and
30 km south-west of Worcester (population 98 800), in Herefordshire, UK
(ONS, 2012). The land surrounding the tower is primarily used for
agricultural purposes and there are 25 waste water treatment plants within a
40 km radius of the site, the majority of which are in the northeast to
south-easterly wind sector (DEFRA, 2012). Air samples are taken from
inlet lines located at 45 and 90 m a.g.l. from a tall open-lattice
telecommunications tower at 204 m a.s.l. N
TAC is a rural UK site located towards the east coast of England (Fig. 1). It
is 16 km south-west of Norwich (population 200 000), and 28 km east of
Thetford (population 20 000), in Norfolk, UK (ONS, 2012). Lines sample air
at 54, 100, and 185 m a.g.l. from a tall open-lattice telecommunications
tower at 56 m a.s.l. CO
TTA is a rural UK site located near the east coast of Scotland (Fig. 1). It
is 10 km north of Dundee (population 148 000; GRO, 2013). A single line
samples air at 222 m a.g.l. from the tall open-lattice tower at 400 m a.s.l., which measures CO
Schematic diagram of the UK DECC network (Angus, TTA; Ridge Hill,
RGL; and Tacolneston, TAC) CO
GHG measurement systems were developed in 2011 and then deployed in 2012 to enable measurements of GHGs from telecommunication towers within the UK. The system designs are similar to sampling equipment already deployed at Mace Head (Prinn et al., 2000) and at other tall tower sites (Popa et al., 2010; Winderlich et al., 2010). The systems are designed to utilise easily obtainable parts, so that rapid replacement is possible on component failure, thus minimising system downtime and data gaps. This section outlines the instrumental setup used within the UK DECC network to measure GHGs. Table 1 summarises the trace gas species measured at each of the sites and the instrumentation used. Figure 2 shows a schematic diagram for TTA, RGL and TAC, whereas the MHD setup is outlined in Prinn et al. (2000).
At all UK DECC sites, instrumentation is located at the base of the towers
in a building or a modified shipping container. At RGL and TAC, air is
sampled through
Once the sample lines enter the laboratory, whole air samples pass through
an inline 40
The sample line setup at TTA was different to the two other UK sites (RGL
and TAC) as this site had previously been managed by the University of
Edinburgh before being transferred to the University of Bristol (UoB) from
January 2013. Specific differences at TTA include that the sample inlet does not
have a protective cup covering it (the air sampling line is cut on a bias so
H
Each sample line has its own dedicated oil-less linear pump (DBM20-801, GAST
Group Ltd, UK; TTA: Capex L2, Charles Austin, UK), continuously flushing at
a flow rate of
Cavity ring-down spectrometers (CRDSs) subsample from the main sample lines, passing through the sample selection system and a Nafion dryer (described in Sect. 3.3). CRDS instrument pumps (MD1 pump, Vacuubrand GmbH & Co. KG, UK) are located downstream of the analyser. This has the advantage of eliminating sample contamination from the pump, reducing the likelihood of a torn diaphragm introducing laboratory air into the sample. The CRDS outlet valve pressure is monitored as a diagnostic for instrument pump failure. The CRDS instrument pump uses polytetrafluoroethylene (PTFE)/Viton® (also known as FKM) diaphragms. CRDS MD1 instrument pumps are located in the ambient internal laboratory air to allow efficient cooling from the fitted heat sink.
All gas chromatograph (GC) systems and reduction gas analysers (RGAs) use a
similar line pump setup (described above), housed within a custom-built GC
instrument sample module (Fig. 2). A KNF pump (N86 STE, KNF Neuberger UK
Ltd, Oxfordshire, UK) is located downstream of the diaphragm pump, which
subsamples at a flow rate of 6 L min
CO
The CRDS systems measure the decay time of the pulse of laser light inside a
35 cm
H
In addition to using permeation Nafion dryers, a data correction can also be
applied to remove spectral effects caused by H
The CRDS instruments at TAC and RGL were fully operational for > 98 % for the time period reported here. The TTA CRDS was operational for
> 93 %. The inlet at Angus was not shielded from rainwater by
an inverted cup, as was the case at other sites, and access to the site was
more difficult due to its remote location. As a result, the H
Gas chromatograph–flame ionisation and electron capture detector equipment and setup at UK DECC stations.
N
ECD frontend valve configuration for sample backflush, heart cut and analysis at Tacolneston (TAC) and Ridge Hill (RGL). The MHD setup is outlined in Prinn et al. (2000).
The SF
The main difference between the method used in our systems and those
described by Hall et al. (2011) is the use of P5
carrier gas instead of CO
The three valves (Valco universally actuated, RS-232 communication, purged housing) are controlled remotely using GCWerks, enabling automatic sampling (see Sect. 3.8).
Reduction gas analyser equipment and setup at UK DECC stations.
CO and H
The Medusa is a custom-built pre-concentration unit coupled to a gas
chromatograph–mass spectrometer (GC-MS, the entire system is hereafter
referred to as a Medusa GC-MS), which measures a wide range of GHGs and
ODSs. The Medusa GC-MS system is used at both MHD and TAC to measure
SF
All instruments within the UK DECC network are controlled by GCWerks, installed on a local site computer running Ubuntu 12.04 LTS. GCWerks automates all instrument parameters (valves, trap and column temperatures, mass flow controllers, etc.), regulates switching processes, controls calibration cycles, displays chromatograms, performs peak integration and gives graphical and tabulated displays of all results. The automation of all instrumental processes helps to reduce problems and data loss associated with connection problems between independent sample modules to instruments.
GCWerks generates automated user-specified alarms when instrument parameter conditions are not met. These alarms can also initiate instrument shutdown when specified to prevent instrumental damage.
The local site computer is connected to CRDS and GC analysers via Ethernet and the sample selection systems communicate through serial (RS232) connections. Each site has a broadband internet connection which is utilised for remote access and control, automated data backup and maintaining system time synchronisation for each computer using the network time protocol. Data from instrumentation and ancillary equipment are logged and archived at all sites at a frequency of 0.3–20 Hz.
Uninterruptible power systems (UPSs) are used at MHD (SG5K-6K, Falcon Electric Inc., USA), RGL and TAC (Sentinel Dual SDL8000, Riello UPS Ltd, UK) to prevent power surges and temporary power outages affecting instrumentation. The UPS provides up to 20 min of power to instrumentation in the event of a power outage. Additionally, an on-site generator provides continuous backup power at MHD with the UPS providing power for long enough to enable a seamless transition of power from line to generator.
Maintenance schedules of each of the sites varies greatly depending on instrumentation; sites with Medusa GC-MSs (TAC and MHD) were visited more frequently due to the instrumentation being complicated and having greater maintenance needs and sites with only CRDSs were visited the least. Table 5 outlines routine site visits, as well as emergency visits when issues with the instrumentation arose that could not be rectified remotely. Scheduled site visits included checking calibration cylinder pressures and line pump flow rates, changing of carrier gases, updating software on instruments and computers at site, emptying water decanting bowls of any liquid water, and changing line and equipment (compressor and zero-air generator) filters.
Sampling sequences within the network varies between instruments. CRDS instruments within the network are continuously measuring, with RGL and TAC measuring each sampling height sequentially for 30 and 20 min, respectively, to ensure each sampling height is measured within each hour. The CRDS at TTA measures continuously from the single 222 m inlet. To ensure a good stabilisation period when sampling between different heights, the first 2 min of data after the valve switches to a new sample intake is automatically flagged out. The air sampling sequence is interrupted to analyse a daily standard gas and a monthly calibration sequence, outlined in Sect. 4.2.1.
Maintenance schedule for all UK DECC sites from January 2012 to September 2015. N/A: no emergency site visits were made.
The GC-ECD, RGA and Medusa GC-MS all have a lower sampling frequency than CRDSs and therefore only sample from one inlet. Sampling frequencies within the network are 10 min for the GC-ECD at RGL and TAC, 20 min for GC-FID and GC-ECD at MHD, 10 and 20 min for the RGA at TAC and MHD, respectively, and 65 min for the Medusa GC-MS. Measurements alternate between ambient air and calibration gas, as outlined in Sect. 4.2.2.
To guarantee the reliability and stability of measurements, automated
calibrations are carried out periodically. Two separate calibration schemes
are used, one for the CRDS and another for all other instruments. All tubing
used for calibrant gases are
CRDS instruments have two types of calibration standards, a standard of
approximately ambient mole fraction and a set of calibration standards that
span from below ambient up to elevated mole fractions. High-pressure
aluminium tanks (Luxfer Gas Cylinders, UK) are used rather than steel to
ensure long-term stability of CO
Cavity ring-down spectrometry calibrant (cal) and standard gas mole
fractions for CO
The standard gas is measured once a day for 20 min to assess for linear
instrumental drift, and the suite of calibration gases with varying mole
fractions is measured once a month in quintuplicate to assess for
instrument non-linearity and non-linear drift. The first 5 min of
standard and calibration data and the first entire suite of calibration runs
are removed to compensate for variability caused by regulator and line
flushing. Table 6 details the standard and calibrant CO
An example of a non-linear fit used for
Instrument non-linearity is assessed on a monthly basis by manually viewing
the curve of the calibration gases and adjusted accordingly if there is a
difference between the previous and current curve coefficients. Instrument
non-linearity is also reassessed after changes in instrumental soft- and
hardware. Despite other studies showing CRDSs to be linear (Yver Kwok et
al., 2015; Hazan et al., 2016) over the concentration ranges used in the
network, all instruments were found to have a small non-linear response
(example shown in Fig. 4). Therefore, a second-order non-linear curve is fit
to the data and implemented in GCWerks manually (see Sect. 5.1). There is a
possibility that this is an artefact from the calibration cylinders;
however, the non-linearity effect has also been seen when NOAA (National
Oceanic and Atmospheric Administration) cylinders have been used to
calibrate instruments. There is a small difference (median
The long-term repeatability of daily standard measurements
(standard deviation, 1
The MHD GC-ECD, GC-FID, RGA, and Medusa GC-MS instruments and the TAC Medusa GC-MS are calibrated using tertiary standards. Working standards (also known as quaternary standards) are used to calibrate the Medusa GC-MS systems within the network and the GC-ECD and RGA at TAC and RGL. Tertiary and quaternary standards are prepared by compressing background ambient air into 34 L electropolished stainless steel cylinders (Essex Cryogenics, Missouri, USA) using a modified oil-free compressor (SA-3, RIX California, USA). Tertiary standards are filled at La Jolla, California, USA, and calibrated at Scripps Institution of Oceanography (SIO) against their primary calibration scales via secondary working standards before being sent to MHD or TAC. Tertiary standards are also re-calibrated on return from site to assess each standard for sample stability over its working lifetime. Quaternary standards are filled at MHD and are calibrated/re-calibrated against the SIO-calibrated tertiary standards at MHD on the GC-ECD and RGA before and after use at the tall towers. Mole fractions within the tertiary and quaternary standards are close to ambient background air sample values, minimising possible sample matrix non-linearities.
The quaternary standards are used to bracket air measurements on the GC-ECD,
GC-FID, RGA and Medusa GC-MS. Tertiary standards are used to bracket air
measurements on the MHD GC-ECD/FID/RGA. In addition, for the Medusa GC-MS,
tertiary standards are analysed weekly and are used to calibrate the
quaternary standards over the course of their use in the field. Quaternary
standards last for two months to two years, depending on which instrument
they are being used to calibrate, and tertiary standards last approximately
eight months to two years. Studies have shown that no significant drift of
species contained in these standards occur over this time period
(Hall et al., 2007, 2011).
Calibration scales vary depending on the gas species, with N
Repeatability of 20 min injections of tertiary/quaternary standards
(1
Due to the non-linear response of the GC-ECD to N
GCWerks is used to process all of the CRDS, RGA and GC data. Raw
measurement data and ancillary parameters stored on the local site computers
are processed on site in near-real time (NRT) for calibration and H
Raw and processed data are mirrored daily from the local site computer to
data processing servers at the UoB or at the University of East Anglia (UEA)
for TAC GC-ECD/RGA and Medusa GC-MS. Post-processed UEA data are also
mirrored to the UoB servers for archiving. All raw and processed data
(calibrated and H
Raw CRDS data and ancillary parameters are acquired by GCWerks and are
stored in binary stripcharts. These stripcharts contain all relevant data
from the CRDS, i.e. wet and dry mole fractions, H
A number of data filters are automatically applied to the CRDS data before 1, 5, 10, 20 and 60 min means are calculated. These filters remove, for instance, cavity pressure and
temperature out of normal operating range, high H
Parameters used in GCWerks for automatic CRDS data filtering until September 2015.
CRDS measurements are then corrected for linear instrumental drift and
instrumental response over a span of different mole fractions, referred to
here as non-linearity. As in Verhulst
et al. (2017), linear instrumental drift, monitored by repeated measurements
of a calibrated standard gas measured daily for 20 min, is corrected for
by the ratio of a measurement to the linear interpolation between bracketing
standard measurements, as outlined in Eq. (1). However, unlike in
Verhulst et al. (2017), instrumental
non-linearity is assessed and implemented using a function of the
sample / standard ratio, outlined in Eq. (2). A second-order function can then
be fitted to the data to provide a non-linearity correction in Eq. (1).
GC data and ancillary parameters are acquired by GCWerks and stored in chromatograms and stripcharts, as well as being displayed in real time. Temperature (ambient and sample selection module), loop flow rates and pressures at the time of sample injection onto the columns are also stored in a sample log file with the corresponding date and time.
User defined integration parameters allow for automatic integration of peaks. Chromatograms can be reprocessed for selected periods when peak integration parameters need to be altered due to changes in baseline and retention times. Integrated peak heights and areas are stored and used along with pressure and temperature data stored in the sample log file to calculate mixing ratios.
N
Histograms of the difference between linear corrected data (Eq. 1)
and non-linear corrected data (Eq. 2) for CO
In the first phase, chromatograms and stripcharts are reviewed daily, on a site-by-site basis to check for good integration and systematic biases not detected by automatic data processing routines. Filtered data are also reviewed in the stripcharts, shown in conjunction with the unfiltered data, to ensure good filter parameterisation, ensure non-spurious data are not unnecessarily filtered out and help diagnose instrumental issues. Data and ancillary measurements are reviewed in parallel to help observe potential errors and diagnose issues within the data. Instrument precision is reviewed by monitoring the standard gas concentrations for anomalies. To further investigate data issues, 1, 5, 20 and 60 min mean (CRDS) or discrete (GC-ECD/FID/RGA and Medusa GC-MS) air data can also be plotted against instrumental and ancillary parameters. Spurious data are manually flagged and a justification for the flagging of data is given and logged.
In the second phase, data from the entire network are imported and reviewed simultaneously in GCcompare, custom-built data visualisation software for time series data from multiple sites. Flagged GCWerks time series data from the network are overlain to compare sites with the background station (MHD) and to look for differences between sites for each compound measured in the network. Potential issues not previously noted are investigated using ancillary and instrumental parameters, which are also imported into GCcompare, as well as air-history maps produced on an hourly basis using the Numerical Atmospheric dispersion Modelling Environment (NAME) Lagrangian dispersion model outlined in Manning et al. (2011).
Collection, storage and visualisation of ancillary data in GCWerks in parallel with mole fraction data have made troubleshooting data issues easier. When potential issues are observed in the time series data, site operators check the ancillary data recorded to try and help identify potential issues.
Troubleshooting data issues observed in the UK DECC network from it starting in 2012 to September 2015.
Within the network, one of the greatest issues observed so far is laboratory temperature stability, which can affect the performance of the instrumentation. At sites with and without air conditioning, rapid fluctuations in temperature have resulted in poorer precision in the data, as observed in the ambient temperature data recorded on the GC-ECDs. In laboratories with air conditioning (TAC and MHD), economy modes have often been used to reduce the frequency of the unit being switched on and off, thus smoothing the temperature swings in the laboratory. At RGL, the ventilation system is set to being either constantly on in the summer or off during the winter months to smooth temperature fluctuations in the laboratory. A number of other issues observed within the network are shown in Table 8.
Measurements of GHGs from the UK DECC network are presented from January 2012
through to September 2015 (Figs. 6 to 8; see Sect. 2 for details of start
dates of data acquisition). Results shown in this paper are limited to
qualitative analyses of the most prominent features of the data; utilisation
of this large and comprehensive dataset to its full potential lies in the use
of high-resolution inverse atmospheric transport models (Manning et al.,
2011; Vermeulen et al., 2011; Ganesan et al., 2015). All CO
CO
Time series of
CH
A seasonal cycle is also observed in N
Time series of
Tropospheric SF
A seasonal cycle is also observed in CO and H
Time series of
In principal, measurements of GHGs at different heights at a station allow
observations of sources and sinks from different spatial footprints
(Vermeulen et al., 2011). The average diurnal
profiles for CO
The greatest difference in CO
Overview of average diurnal concentration gradients in CO
Diurnal variation in CH
Air history maps, showing the previous 30 days of surface influence at the
station in a 1 h period, were produced using the Met Office NAME
Lagrangian atmospheric dispersion model (Jones et al.,
2007) for each of the sites within the UK DECC network in order to discern
and explain pollution signals in the mole fraction measurements. Increasing
mole fractions with longitude across the UK from the baseline station (MHD)
are frequently seen within the data, as demonstrated in Fig. 10a on
5 December 2014. Figure 10b also demonstrates a regionally polluted
period at RGL for CH
Examples of
Many lessons have been learnt with setting up and running the UK DECC network and we have tried to summarise the main points for future stations or networks.
Monitoring stations are often located in remote areas that are not easily accessible. The need for designing instrumentation that can be fully automated and controlled on site with minimal on-site human attention is extremely important. Additionally, it is crucial that the software used to control the instrumentation can be accessed remotely to make changes to sampling regimes when issues arise. As suggested by Andrews et al. (2014), modularity in the analytical systems helps simplify maintenance and repairs. We aim to have spare modules, such as line pump modules, based in the UoB laboratory that can be sent or taken to site as soon as there is a sign of an imminent problem. This is not always feasible for larger and more expensive items, such as instrument boards; however, these items do not fail as frequently as line pumps or inlet filters.
A number of software packages are now commercially available and are able to control instruments and log data. However, there are fewer packages available that are able to control instruments, log data and visualise data rapidly. Being able to visualise all data, including ancillary data and even after the data have been post-processed, at the site has the added advantage of being able to look back through the time series for when an issue may have previously happened and then check the operations log to see how the problem was rectified. This is especially important when a number of site operators make visits.
Comprehensive measurement and logging of critical pressures, temperatures and flow rates are necessary for detecting instrumental problems. Automated alarm emails based on the data can notify site operators of failures and help to reduce instrument downtime. Prior to the alarms being integrated within the network, problems with the data and instruments went unnoticed for several days. Customisation of alarm parameters can also help to reduce false alarms.
High-precision data require frequent field calibration, even for modern
CO
It is recommended to have more than the minimum number of calibration cylinders required to generate a calibration curve depending on the instrument needs; however, space and financial constraints can reduce the number of cylinders available. As a guide for CRDS instruments, we have a minimum of three calibration cylinders and one standard cylinder per analyser. We also recommend having spare standard and calibration cylinders, which can be kept off site, in case cylinders need urgently replacing following failures. Standard cylinders should be at ambient mole fractions and calibration cylinders should span the expected ambient range. Standards and calibrants should have the same matrix as the sample air and a similar isotopic composition to ambient air.
On a number of occasions, P5 and He carrier gases have been contaminated
with SF
The UK DECC network was established in January 2012 to monitor atmospheric GHG and ODS mole fractions and verify the UK emission inventories submitted to the UNFCCC. The network was expanded from MHD, where GHG and ODS measurements have been made since 1987, to include RGL, Herefordshire, England; TAC, Norfolk, England; and TTA, Dundee, Scotland.
We have designed a network with robust systems for unattended continuous
measurement of atmospheric CO
Future improvements for the network include instrument specific H
In situ atmospheric greenhouse gas data from the UK DECC
network is available online. Discrete sample and hourly mean data are freely
available from EBAS at
The authors declare that they have no conflict of interest.
This article is part of the special issue “Greenhouse gAs Uk and Global Emissions (GAUGE) project (ACP/AMT inter-journal SI)”. It is not associated with a conference.
We specifically acknowledge the cooperation and efforts of the station operators Gerard Spain and Duncan Brown at Mace Head monitoring station, and Stephen Humphrey and Andy MacDonald at the Tacolneston tall tower station. We also thank the Physics Department, National University of Ireland, Galway, for making the research facilities at Mace Head available. The operation of all stations was funded by the UK Department of Business, Energy and Industrial Strategy (formerly the Department of Energy and Climate Change) through contract TRN1028/06/2015 with additional funding at Mace Head under NASA contract NNX11AF17G through MIT with a sub-award 5710002970 to the UoB. Edited by: Marc von Hobe Reviewed by: two anonymous referees