DOI: 10.5281/zenodo.4335462
title: NYTEFOX - The NY-Ålesund TurbulencE Fiber Optic eXperiment investigating the Arctic boundary layer, Svalbard

description: Atmospheric processes in the weak-wind stable boundary layer are an open field of research since they are poorly represented by theoretical concepts including similarity theories commonly applied in the air layer adjacent to the surface. This lack of understanding affects polar regions the most since the observation density is sparse while the fraction of weak-wind conditions with strong static stability increases drastically during polar night which is characterized by a long-lived stable boundary layer. The atmospheric motions carrying the bulk of the near-surface transport in these conditions occur on scales larger than forced or free convective turbulence, show different characteristics and are known as submeso-scale motions. These submeso-scale motions cannot be resolved by common point measurements due to their quasi-stationary or transient behavior but require distributed observations such as from sensor networks or continuous observational techniques. A suite of observations satisfying these requirements were collected during the Ny-Ålesund TurbulencE Fiber Optic eXperiment, NYTEFOX, which was a field campaign conducted at an Arctic field site at the perimeter of the Ny-Ålesund science station (11.9°E, 78.9°N) in February and March 2020. It was the first field campaign in an Arctic environment to investigate the spatio-temporal variability of airflow and temperature across hundreds of meters horizontally by means of the innovative Fiber-Optic Distributed Sensing (FODS) technique. A 700 m long horizontal, trapezoidal transect of fiber-optic cables installed at 1.2 m above ground level (agl) yielded measurements of temperature and wind speed with a resolution of 0.127 m and 9 s, supplemented by three 7 m tall vertical profiles. A coil-wrapped column of fiber-optic cable, helically wound around a support fabric, added a high-resolution vertical temperature profile from below the snow surface (-0.25 m) up to 2.5 m agl with an effective vertical resolution of 0.0025 m to 0.02 m depending on height. The 14-day FODS data set spanning the period from 26.02.2020 until 10.03.2020 is complemented by observations of three ultrasonic anemometers and one acoustic profiler (miniSodar, SOund Detection And Ranging) measuring a wind profile up to 300 m agl. The NYTEFOX data set allows for exploring the role, as well as the horizontal scales, vertical scales, and the trajectories, of turbulent and submeso-scale motions in the Arctic during the transition from the polar night to spring. The atmospheric observations from this pilot field campaign substantially expand the data set operationally collected by the Basic Surface Radiation Network (BSRN) meteorological data set at Ny-Ålesund, Svalbard by observing airflow and temperatures at turbulent to submeso scales. A technical documentation and file overview is given here (documentation.pdf). A more detailed description of the setup and processing steps as well as an exemplary illustration of the observations on 05.03.2020 can be found in a forthcoming Earth System Science Data (ESSD), whose DOI will be added once it is available in its final form. All data are provided either as comma separated ASCII (csv, for the ultrasonic anemometer statistics) or as self-describing netcdfs. This project has received funding from the Alfred Wegener Institute for Polar and Marine Research (AWI) in Potsdam, the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant agreement No. 724629 DarkMix, PI: Christoph Thomas), and the Research Council of Norway (project number 291644) Svalbard Integrated Arctic Earth Observing System (SIOS) – Knowledge Centre, operational phase. The experiment was conducted with the support of the joint French-German AWIPEV-Station operated by the AWI and the Polar Institute Paul Emile Victor (IPEV) in Ny-Ålesund.