Prof. Dr. Guido Grosse Arctic permafrost landscape dynamics and Earth System feedbacks Permafrost coring in the Fish Creek Delta, North Alaska (Photo: Alfred Wegener Institut) Arctic permafrost landscapes [...] DOCconcentrations, the origin of DOC and the temporal variability in two permafrost regions along the Arctic Ocean. My study areas are the Lena Delta and Bykovsky Peninsula in Siberia, and a transect from Teshekpuk [...] Global warming will continue to warm the Arctic resulting in the degradation of permafrost soils. This leads to large-scale ground subsidence. Vast regions of the Arctic are covered with ice-rich silts containing

sea ice covered regions in the Arctic and Antarctic oceans make satellite remote sensing the only tool that is able to obtain a full picture of sea ice conditions. The Sea Ice Physics section is actively [...] Sea Ice Remote Sensing Map of Arctic sea ice thickness (April 2015) obtained from CryoSat-2 data (Graphic: Alfred Wegener Institut) Contact: Dr. Stefan Hendricks The inaccessibility and sheer size of sea [...] the European Space Agency (ESA) is based on a radar altimeter that fully maps Antarctic sea ice and Arctic sea ice up to a latitude of 88°N. This coverage is unparalleled in comparison with all previous and

which are a set of ocean and sea ice variables optimally combining observations and a model. The analysis fields are applied for a variety of ocean and sea ice studies in the Arctic Ocean, and also provide [...] used to synthesize model results and observed data in the Arctic Ocean. The systems have been successfully applied to North Atlantic/Arctic Ocean Sea Ice Model (NAOSIM) developed at the Alfred Wegener Institute [...] Institute (AWI). We are currently working to apply the systems to Finite-volumE Sea ice-Ocean Model (FESOM2), also developed in AWI. Contact: Dr. Hiroshi Sumata Seasonal cycle (left) and interannual variation

the Eurasian shelf seas. Ocean waters with salinities below the average salinity of the Arctic Ocean also contribute positively to the fresh water balance of the Arctic Ocean. Such waters flow in from [...] shows the total Arctic (liquid + sea ice) freshwater content (integrated in the area in blue on the map) freFresh water content cha (Graphic: T. Kovacs, Alfred-Wegener-Institut) The Arctic Ocean receives freshwater [...] interchange of waters between the Arctic and the Nordic seas results in in seasaw fluctuations in fresh water content between the basins. To reach an equilibrium, the Arctic Ocean must on averageexport freshwater

production of data set time series of variables that describe the state of the atmosphere, land, ocean and the cryosphere. Sea ice is listed as one of the 13 Essential Climate Variables and the aim of [...] group is to produce datasets of sea ice concentration sea ice thickness sea ice drift that include Arctic and Antarctic sea ice and the respective uncertainties. The data sets both parameters will consist [...] thickness time series from data of the ERS-1, ERS-2, EnviSat and CryoSat-2 radar altimeter missions of Arctic and Antarctic sea ice. The production of a time-series of Antarctic sea-ice thickness is based on

moderately rough arctic sea ice and take ridge height and distribution into account. They are well proven for applications in simulations of flow situations in the northern polar ocean. To prove if they [...] leads and polynias For the energy and moisture exchange between the atmosphere and the ice covered ocean, leads and polynias play an important role. This is documented by many modelling studies, but only [...] sea ice have a significant effect on the energy exchange between the atmosphere and the ice covered ocean. Uncertainties in the representation of sea ice albedo contribute considerably to the differences

sensitivity experiments addressing questions such a What would happen to the global climate system if Arctic sea ice vanished? Climate models are also used in the Climate Dynamics section to carry out predictions [...] Traditionally, theoretical work in the Climate Dynamics section focusses on the behaviour of the ocean.

institutions in 3 European countries studied processes of the energy transfer between the ocean and the atmosphere in the Arctic. The project was conducted from 1998 to 2000 with a major field campaign involving [...] addressed the effects of clouds and of Arctic Haze on the radiative fluxes at the surface and in the atmospheric column for various states of the surface in the European Arctic. Major emphasis was put on convective [...] over the ice-free ocean and on stratiform clouds at low levels and their radiational exchange with sea ice. The effects of clouds on the radiative fluxes for various states of the ocean surface were studied

rview.html Arctic Ocean Science Board : The Board supports large-scale multinational and interdisciplinary Arctic research projects. www.aosb.org Arctic ROOS : Arctic Regional Ocean Observing System [...] hic Information System (OBIS). www.iobis.org Ocean Colour Data Portal . oceanographicdata.org/REASoN_OceanColorDataPortal.html OceanSITES : A global network of deap sea reference stations [...] for the study of atmosphere-ocean interactions in the tropical Atlantic. www.pmel.noaa.gov/pirata/ POGO: Partnership for observation of the global ocean. www.ocean-partners.org/ PISCO : long-term

Earth System Models We simulate Arctic sea ice for the past, current and possible future climates, with regional sea ice-ocean and Earth System Models. Regional ocean-sea ice models have the advantage [...] al., 2014 ). We test those parameterizations in regional sea ice ocean models such as NAOSIM ( Köberle and Gerdes, 2003 ) and an Arctic model set-up of the MITgcm ( Castro-Morales et al., 2014 ). After [...] usually much coarser spatially resolved but have the advantage of simulating the atmosphere model, the ocean and the sea-ice simultaneously. Earth System Models (ESMs) additionally include vegetation and chemistry