Station North

Site description

Station North, also called Villum Research Station (http://villumresearchstation.dk), is a research facility at a military outpost in high arctic North Greenland (81°36’ N, 16°40’ W). It is owned by the Greenland Government and is being operated by Aarhus University (Denmark) in cooperation with the Danish Defense (the Arctic Command). Observations are part of the European ICOS observation network, and the MPG flask sampler has been integrated into this concept.

Instrument

Our flask sampler at Station North can be used for the automated collection of air samples (1 – 3 L) under standardized conditions. The sampler version used here is a smaller version compared to the standard ICOS design, consisting of just 3 drawers, therefore capable of holding up to 12 flasks at a time. The integrated software allows for a detailed monitoring of flow processes and flask status. Flasks are analyzed at MPI-BGC for the concentrations of CH₄, CO₂, CO, N₂O, H₂, and SF₆. As additional parameters, we sample the ratios of O₂/N₂, Ar/N₂, and the stable isotope signals d¹³C-CO₂, d¹⁸O-CO₂, d¹³C-CH₄, and d²H-CH₄.

Results

Operations at Station North started in September 2019. The below Figure summarizes the seasonal variability and mid-term trends for six major trace gases that are routinely quantified in the sampled flask air: CH₄, CO₂, CO, N₂O, H₂, and SF₆.

Integrated time series of GHG mixing ratios across all sampling strategies, with orange crosses indicating individual measurements, and blue lines a moving-window average to highlight seasonal variability and mid-term trends. Top row: CO2 and CH4; Center row: N2O and H2; Bottom row: CO and SF6. @IPAS Group — Integrated time series of GHG mixing ratios across all sampling strategies, with orange crosses indicating individual measurements, and blue lines a moving-window average to highlight seasonal variability and mid-term trends. Top row: CO₂ *and CH*₄*; Center row: N*₂*O and H*₂*; Bottom row: CO and SF*₆*. @IPAS Group*

Integrated time series of GHG mixing ratios across all sampling strategies, with orange crosses indicating individual measurements, and blue lines a moving-window average to highlight seasonal variability and mid-term trends. Top row: CO₂ *and CH*₄*; Center row: N*₂*O and H*₂*; Bottom row: CO and SF*₆*. @IPAS Group*

Time series of trace gas ratios, and isotope signals

Figure 6 summarizes the measured times series of the O₂/N₂, Ar/N₂ ratios, and the stable isotope signals for CO₂ (d¹³C-CO₂, d¹⁸O-CO₂) and methane (d¹³C-CH₄, and d²H-CH₄). These signals primarily aim to support the interpretation of large-scale representative concentration levels of these components, potentially improving estimations of their continental fluxes with the help of inverse modelling. These data become particularly interesting when comparing results between different source regions for the air masses sampled.

Time series of trace gas ratios (top row), CO2 isotope data (center row) and CH4 isotope data (bottom row). Boxes summarize observations at monthly timesteps, with horizontal bars showing the median, colored boxes the interquartile range, and whiskers the range between minimum and maximum observed trace gas levels, respectively. @IPAS Group — *Time series of trace gas ratios (top row), CO*₂ *isotope data (center row) and CH*₄ isotope data (bottom row). Boxes summarize observations at monthly timesteps, with horizontal bars showing the median, colored boxes the interquartile range, and whiskers the range between minimum and maximum observed trace gas levels, respectively. @IPAS Group

*Time series of trace gas ratios (top row), CO*₂ *isotope data (center row) and CH*₄ isotope data (bottom row). Boxes summarize observations at monthly timesteps, with horizontal bars showing the median, colored boxes the interquartile range, and whiskers the range between minimum and maximum observed trace gas levels, respectively. @IPAS Group

Aggregated signals separating source regions of air masses

The analysis of time-integrated signals from five different source regions demonstrates systematic differences between different source regions, particularly for the isotopic signatures in the CH₄ molecules. CO₂ isotopes, on the other hand, revealed higher variability in the signals, with mostly overlapping ranges between regions.

The results displayed below are a promising indication that long-term integrated sampling of trace gas signatures can provide valuable insights into the specific source region signatures of air mass composition, and can therefore support the attribution of individual, instantaneously filled samples according to their origin, this way supporting the validation of atmospheric transport modeling.

Figure 7: Signals of trace gas ratios (top row), CO2 isotope data (center row) and CH4 isotope data (bottom row) separated by source region of the air masses (see also Figure 4). @IPAS Group — *Figure* 7: Signals of trace gas ratios (top row), CO₂ *isotope data (center row) and CH*₄ *isotope data (bottom row) separated by source region of the air masses (see also* *Figure* 4). @IPAS Group

*Figure* 7: Signals of trace gas ratios (top row), CO₂ *isotope data (center row) and CH*₄ *isotope data (bottom row) separated by source region of the air masses (see also* *Figure* 4). @IPAS Group

Accessibility of the obtained data sets and repositories used

All datasets from the MPG flask monitoring program at Station North were stored at the Edmond repository hosted by MPG: https://dx.doi.org/10.17617/3.6p

@IPAS Group