Gas samples (CO2, CH4, CO, N2O, 13CO2, 14CH4, 13CO, C18O, 14CO) are collected from an inlet atop of a mast 5 metres above ground level in North sector wind conditions. Flasks and cylinders are analysed back at NIWA Greta point Gaslab. The sampling was established in November 1989. Samples are only taken when wind is from the Northerly sector and above 5kts. High pressure cylinders: ~1600psi in 30 litre cylinders and low-pressure flask samples taken (~5 litres, 25 psi in 2 litre flask). Air samples in the Cylinders & Flasks shipped to New Zealand regularly. Analysis performed at NIWA's GASLAB located at Greta Point Wellington. Analysis by Gas chromatography (GC) and isotope ratio mass spectrometry (IRMS). A semi-automated flask sampling system was installed in February 2017, allowing extra flask samples with minimal operator intervention. GET DATA: Contact Gordon Brailsford (g.brailsford@niwa.co.nz)

Measurements of partial and total column of several atmospheric trace gases (e.g.O3, HCl, N2O, CH4, HNO3, ClONO2, HCN, HF, OCS, CO, C2H6, CFC-11, CFC-12, COF2 + others). Measurements are made with Bruker Fourier transform spectrometers, using direct sunlight (or moonlight) at infrared wavelengths (700-10000cm-1). The Bruker FTS instruments have two liquid nitrogen cooled detectors (inSb & HgCdTe) and six optical filters. For 2014-2016 seasons, operated in parallel with Bruker 120M for intercomparison studies. Bruker 120M will then be retried. Bruker 125HR will replace it. Data are routinely analysed for HNO3, HCl, CH4, N2O, CO, ClONO2, HF, C2H6, HCN, and 10+ other species measurable. Information on other trace gases is contained in the spectra, not yet analysed/retrieved. “Raw” data are times and recorded interferograms which are Fourier transformed into spectra. “Derived” data are column amounts, and in some cases limited vertical profile information, of atmospheric trace gases. Technique for vertical profile information uses "optimal estimation" to extract information from pressure broadening of absorption lines: SFIT2/SFIT4. The original solar tracker was replaced with a newer tracker in December 2017, active tracking of sun now possible. A Bruker EM27-Sun operated for a summer season at AHTS, to access capability. Measurements of total column CO2, CH4 and CO. Data archived as part of the COCCON network. Instrument timeline: - Bomen DA2 FTS 1990-1994 (HNO3 and HCl only) - Bruker 120M: 1996-2016 - Bruker 125HR: 2015 – present - EM27-Sun: Campaign based low resolution instrument (CO2, CH4 and CO only). February 2016 and then November 2020 – February 2021 GET DATA: https://www-air.larc.nasa.gov/missions/ndacc/data.html?station=arrival.heights GET DATA (EM27-Sun): https://www.imk-asf.kit.edu/english/COCCON.php