Reply to the comments of Anonymous Referee #1’s report on the manuscript “Greenhouse gas measurements from a UK network of tall towers: technical description and first results”

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 15 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 20 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 (1s on 1-minute 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 25 of standard injections (1s) 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