wCONTINUOUS MEASUREMENTS OF CARBON DIOXIDE AND METHANE MOLE FRACTIONS IN THE ARCTIC ZONE OF CENTRAL SIBERIA: AN INTRODUCTION TO A NEW COASTAL SITE DIKSON.

Vast carbon reservoirs hosted in the Arctic realm may trigger a significant positive feedback loop in the global Earth climate system under existing global warming scenarios. Nevertheless, sparse coverage of the Arctic region with greenhouse gas (GHG) observation network limits our understanding of carbon cycling in this environment and making predictions about a fate of carbon conserved in currently frozen ground. Especially critical gaps exist in the vast Arctic territories of Siberia, where solely 3 continuous atmospheric carbon observation stations are currently operational and located entirely in Northeastern Siberia: atmospheric carbon observation station Ambarchik (69.62° N, 162.30° E), the Tiksi hydrometeorological observatory (71.6°N, 128.9° E) and the Cape Baranova ice base observatory on the Bolshevik Island, Severnaya Zemlya (79.3° N, 101.8° E). In this paper we introduce a newly established coastal atmospheric carbon observation station Dikson (73.33° N, 80.34° E), jointly maintained by the V. N. Sukachev Institute of Forest SB RAS (Krasnoyarsk, Russia), Joint Directorate of Taimyr Nature Reserves (Norilsk, Russia) and the Max Planck Institute for Biogeochemistry (Jena, Germany), which is intended to fill the gap in the atmospheric GHG observations in the northcentral Siberian domain. The general west wind drift expected at the location of the site makes it more sensitive to the northern latitudes of Western Siberia, as compared to the other, more eastern, stations, which, due to the specific cyclonic activity that prevents air from the Icelandic low pressure minimum spreading towards the east of Severnaya Zemlya. The measurement site, which was launched in September 2018, is located on the Taimyr Peninsula near the gulf of the Yenisei River at the coast of the Kara Sea. Atmospheric mole fractions of CO2, CH4 and H2O at the station are continuously measured by an analyzer based on the cavity ring-down spectroscopy (CRDS) technique (G2301-f, Picarro Inc., USA). Data quality control of trace gas measurements is achieved by regular calibrations against WMO-traceable reference gases, an applied water vapor correction and meteorological records that permit data screening. A preliminary wind analysis and calculated backward trajectories from hot spots downwind of the measurement site reveal that during late spring and summer tundra landscapes of the upper part of the Taimyr Peninsula, the gulf of the Yenisei River and the adjacent shelf areas of the Arctic Ocean are the major contributors to the observed variability at the station. Conversely in winter (frost period) this site becomes receptive to air masses originated in the continental domain and containing the anthropogenic GHGs, e.g. the gas production on the Tazovskiy Peninsula. Here we summarize the scientific rationale of the new site, give technical details of the instrumental setup, analyze the local environments and present some exemplary results. [ABSTRACT FROM AUTHOR]