Huhn, Oliver; Rhein, Monika; Bulsiewicz, Klaus; Sültenfuß, Jürgen; Mertens, Christian (2026): Noble gas (He and Ne isotopes) and transient tracer (CFC-12 and SF6) measurements from Maria S. Merian cruise MSM85 (east Greenland, 2019) [dataset]. PANGAEA, https://doi.pangaea.de/10.1594/PANGAEA.995442 (DOI registration in progress)

In total we took 723 water samples for stable noble gas isotopes (3He, 4He, 20Ne, 22Ne) in copper tubes from 77 stations along 8 subsections along the east Greenland coast, shelf, and slope. The water samples were stored from the CTD/water bottle system without contact to atmospheric air and preventing air bubbles into gas tight copper tubes, which are clamped of at both sides. In the IUP Bremen noble gas lab the samples were pre-processed with a UHV (ultra high vacuum) gas extraction system. Sample gases are transferred via water vapour into a glass ampoule kept at liquid nitrogen temperature. For analysis of the noble gas isotopes the glass ampoules are connected to a fully automated UHV mass spectrometric system equipped with a two stage cryogenic system. Regularly, the system is calibrated with atmospheric air standards (reproducibility <0.2%). Also measurement of line blanks and linearity are done. The performance of the Bremen facility is described in Sültenfuß et al. (2009). For the transient tracers (chlorofluorocarbons, CFC-12 and SF6), we took 450 samples on 49 stations along 8 subsections along the east Greenland coast, shelf, and slope. The CFC-12 and SF6 water samples from the CTD-bottle-system were stored in 200 ml glass ampoules without contact to the atmosphere during the tapping. Immediately after sampling the ampoules are flame sealed after a CFC free headspace of pure nitrogen had been applied. The determination of CFC-12 and SF6 concentrations in the IUP Bremen gas chromatography lab is accomplished by purge and trap sample pre-treatment followed by gas chromatographic (GC) separation on a capillary column and electron capture detection (ECD). After thermal desorption the released gases were separated on a pre-column of type Aluminia Bond/CFC, 0.54 mm ID x 3m, and a main column of type Aluminia BOND/CFC, 0.54 mm ID x 30 m. SF6 and CFC-12 were then detected on a micro-ECD. The system is calibrated by analyzing several different volumes of a known standard gas. The loss of CFCs into the headspace is considered by a careful equilibration between liquid and gas phase under controlled conditions before the sealed ampoules are opened and a precise measurement of the volume of the headspace. A more detailed description of the measurement system is given by Bulsiewicz et at. (1998). CFC concentrations are calibrated on SIO98 scale (Prinn et al., 2000).

According to the WOCE standards the following flags were applied to each measurement:

flag 2 = good

flag 3 = doubtful

flag 4 = bad

flag 6 = mean of replicates

flag 9 = no measurement (then, the data value is set to -9.000)