Atmosphere

lead: Sabine Eckhardt (NILU), Sandro Dahlke (AWI)

The work group focuses on how large-scale atmospheric dynamics and synoptic patterns influence the Svalbard atmosphere. Studies also cover warm, moist air intrusions from lower latitudes and cold air outbreaks from the Central Arctic. Poleward energy transport and episodic events drive warming, while precipitation—especially snow versus rain—plays a key role in linking atmospheric dynamics to the cryosphere. Circulation weather types (CWTs), cloud properties, aerosols, and trace gases alter shortwave and longwave radiation fluxes. Comprehensive observations—covering air mass properties, cloud and aerosol characteristics, trace gases, and radiative effects—are combined with modeling to understand Arctic climate variability. Ocean-atmosphere aspects are also topic of this WG.

lead: Kerstin Ebell (Univ.Cologne), Nuncio Murukesh (NCPOR), Teresa Remes (MET.NO), Tomasz Wawrzyniak (IGF)

Variations in temperature, humidity, atmospheric stability, and the number and availability of Cloud Condensation Nuclei (CCN) and Ice Nucleating Particles (INP) alter the properties of clouds. This, in turn, leads to changes in the radiative balance, resulting in a warming or cooling effect of clouds on the Arctic surface in different conditions. Furthermore, clouds are the source of precipitation, either as snow or rain, linking the atmosphere to the cryosphere and influencing the region’s hydrological cycle.

The work group will investigate long-term changes of meteorological background conditions, processes that influence cloud formation and properties, the effects of radiation and  the alteration of precipitation.

lead: Hans-Werner Jacobi (Univ.Grenoble), Libo Zhou (IAP-CAS), Andrea Spolaor (CNR), Sanjong Park (KOPRI)

With proceeding climate change, the seasonal surface change between snow cover and tundra ground is shifting. Corresponding changes in albedo influence the radiation balance, as well as the (latent) heat and momentum fluxes between the atmosphere and the surface.

While the duration of the snow-free period extends, the snow-covered period is frequently affected by rain-on-snow events. Moreover, atmospheric long-range transport has an impact on the snow surface by wet and dry deposition of aerosols, including black carbon (BC).

The work group examines the intricate interactions among surface conditions, micrometeorological phenomena, boundary layer structure, and the coupling between atmosphere and surface on local and synoptic scales.  

lead: Stefania Gilardoni (CNR), Christoph Ritter (AWI), Radovan Krejci (Univ.Stockholm), Zhiyong Xie (Hereon), Rita Traversi (Univ.Florence)

Quantifying the impacts of aerosols, greenhouse gases (GHGs), trace gases, inorganic compounds (including sulphuric and nitrous compounds), heavy metals, and persistent organic pollutants (POPs) in the Arctic requires an understanding of seasonally varying long-range pollution transport from lower latitudes, as well as the effects of ice and snow melt, local sources and biological activity, and the dry and wet deposition of aerosol particles, alongside gas-aerosol-cloud interactions.

In Ny-Ålesund, the monitoring of inorganic compounds, heavy metals, and POPs is conducted through in-situ measurements, whereas the abundance of GHGs and trace gases, along with the chemical, optical, and microphysical properties of aerosols, is monitored using a combination of in-situ measurements and remote sensing techniques. The work group’s focus is on analyzing the temporal and spatial distribution of these abundances and properties to facilitate a more comprehensive understanding of pollution sources and pathways, removal mechanisms, and gas-aerosol-cloud interactions and radiative impacts.

lead: tbd

Preliminary: The mesosphere and lower thermosphere (MLT), spanning altitudes from 80 to 120 km, are influenced by general wind circulation, atmospheric waves of various scales, solar radiation, and energetic particle precipitation from space. Understanding the MLT’s thermal structure, dynamics, and composition is crucial, as these are closely linked to the broader atmospheric system.

The temperature of emission layers in the middle and upper atmosphere can be determined through spectral analysis of airglow emissions. The work group focuses on the temporal evolution of auroral emission bands and how gravity and planetary waves, solar thermal tides, and lunar gravitational tides modulate mesospheric and thermospheric temperatures and emission intensity fields.