Denmark/Greenland/Faroe Islands: projects/activities

Projektet har til formål at forlænge og forbedre monitering af to strømsystemer gennem færøsk territorialfarvand, som udveksler vand, varme og salt mellem Arktis og resten af Verdenshavet. Den ene af disse er strømmen af koldt vand fra Arktis gennem dybet af Færøbanke kanalen, som transporterer varme og kuldioxid fra atmosfæren ned i Verdenshavets dybe vandmasser. Den anden er Færøstrømmen, som er den stærkeste transportør af ocean varme mod Arktis med indvirkning på klima, fiskebestande og isudbredelse. Endvidere vil projektet studere opsplitningen af Færøstrømmen i to separate strømgrene med forskellig indflydelse på forskellige områder og processer i Arktis. Projektet vil omfatte feltaktivitet fra sommer 2017 til sommer 2018 med udlagte måleinstrumenter og tilsammen fire hydrografiske togter med forskningsskib. Indsamlede måledata vil blive analyseret sammen med satellit­data og historiske observationer med henblik på at forlænge de ca. 20 år lange tidsserier for de to strømsystemers transporter samt at rationalisere det eksisterende moniteringssystem, således at det i fremtiden vil være mindre afhængigt af kostbare in situ målinger.

In 2013 a new ecosystem monitoring programme “DiskoBasis” was initiated at Arctic Station on Disko Island, Greenland. The project is partly funded by the Danish Energy Agency. The primary objective of DiskoBasis is to establish baseline knowledge on the dynamics of fundamental physical parameters within the environment/ecosystem around Arctic Station. This initiative extends and complements the existing monitoring carried out at Arctic Station by including several new activities –especially within the terrestrial and hydrological/fluvial field. DiskoBasis include collection of data in the following sub-topics; • Gas flux, meteorology and energy balance • Snow, ice and permafrost • Soil and soil water chemistry • Vegetation phenology • Hydrology -River water discharge and chemistry • Limnology -Lake water chemistry • Marine -Sea water chemistry

The ZERO database contains all validated data from the Zackenberg Ecological Research Operations Basic Programmes (ClimateBasis, GeoBasis, BioBasis and MarinBasis). The purpose of the project is to run and update the database with new validated data after each succesfull field season. Data will be available for the public through the Zackenberg homepage linking to the NERI database. The yearly update is dependent on that each Basis programme delivers validated data in the proscribed format.

Changes in surface reflection at the arctic tundra at Ny-Ålesund, Svalbard (79 N) were monitored during the melting season 2002 using a low cost multispectral digital camera with spectral channels similar to channels 2, 3, and 4 of the Landsat Thematic Mapper satellite sensor. The camera was placed 474 m above sea level at the Zeppelin Mountain Research Station and was programmed to take an image automatically every day at solar noon. To achieve areal consistency in the images (which is necessary for mapping purposes) the images were geometrically rectified into multispectral digital orthophotos. In contrast to satellite images with high spatial resolution the orthophotos provide data with high spatial and high temporal resolution at low cost. The study area covers approximately 2 km2 and when free of snow, it mainly consists of typical high arctic tundra with patchy vegetation and bare soil in between. The spectral information in the images was used to divide the rectified images into maps representing different surface classes (including three subclasses of snow). By combining classified image data and ground measurements of surface reflectance, a model to produce daily maps of surface albedo was developed. The model takes into account that snow-albedo decreases as the snow pack ages; and that the albedo decreases very rapidly when the snow pack is shallow enough (20-30 cm) to let surface reflectance get influenced by the underlying ground. Maps representing days with no image data (due to bad weather conditions) were derived using interpolation between pixels with equal geographical coordinates. The time series of modeled albedo-maps shows that the time it takes for the albedo to get from 80% to bare ground levels varies from less than 10 days in areas near the coast or in the Ny-Ålesund settlement till more than 70 days in areas with large snow accumulations. For the entire study area the mean length of the 2002 melting period was 28.3 days with a standard deviation of 15.1 days. Finally, the duration of the snowmelt season at a location where it is measured routinely, was calculated to 23 days, which is very close to what is the average for the last two decades.