A5017925340- Arctic and Antarctic ice dynamics
- Cryospheric studies and observations
- Climate change and permafrost
- Methane Hydrates and Related Phenomena
- Atmospheric and Environmental Gas Dynamics
- Climate variability and models
- Soil Moisture and Remote Sensing
- Arctic and Russian Policy Studies
- Spacecraft and Cryogenic Technologies
- Atmospheric aerosols and clouds
- Icing and De-icing Technologies
- Oceanographic and Atmospheric Processes
- Food Industry and Aquatic Biology
- Atmospheric chemistry and aerosols
- Geology and Paleoclimatology Research
- Meteorological Phenomena and Simulations
- Freezing and Crystallization Processes
- Isotope Analysis in Ecology
- Geological Studies and Exploration
- Atmospheric Ozone and Climate
- Marine animal studies overview
- Smart Materials for Construction
- Marine and coastal ecosystems
- Ocean Acidification Effects and Responses
- Offshore Engineering and Technologies
University of Bremen
2016-2025
University of Cologne
2023
Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)
2021-2023
Norwegian Polar Institute
2013-2022
GFZ Helmholtz Centre for Geosciences
2021
Technische Universität Berlin
2021
Jet Propulsion Laboratory
2009-2017
Universität Hamburg
2005-2010
Hamburg Institut (Germany)
2008
Institute of Oceanography
2007
Recent progress in sea ice concentration remote sensing by satellite microwave radiometers has been stimulated two developments: First, the new sensor Advanced Microwave Scanning Radiometer‐EOS (AMSR‐E) offers spatial resolutions of approximately 6 × 4 km at 89 GHz, nearly 3 times resolution standard SSM/I 85 GHz (15 13 km). Second, a algorithm enables estimation from channels near 90 despite enhanced atmospheric influence these channels. This allows full exploitation their horizontal...
Abstract Clouds play an important role in Arctic amplification. This term represents the recently observed enhanced warming of relative to global increase near-surface air temperature. However, there are still knowledge gaps regarding interplay between clouds and aerosol particles, surface properties, as well turbulent radiative fluxes that inhibit accurate model simulations climate system. In attempt resolve this so-called cloud puzzle, two comprehensive closely coordinated field studies...
[1] We examine the spatial trends in Arctic sea ice drift speed from satellite data and role of wind forcing for winter months October through May. Between 1992 2009, spatially averaged trend within Basin is 10.6% ± 0.9%/decade, ranges between −4% 16%/decade depending on location. The mean dominated by second half period. In fact, five years after a clear break point March 2004, average increased to 46% 5%/decade. Over 1992–2009 period, four atmospheric reanalyses are only 1% 2%/decade....
We examine the basinwide trends in sea ice circulation and drift speed highlight changes between 1982 2009 connection to regional winds, multiyear coverage, export, thinning of cover. The polarity Arctic Oscillation (AO) is used as a backdrop for summarizing variance shifts decadal patterns. 28‐year fields show net strengthening Beaufort Gyre Transpolar Drift, especially during last decade. imprint arctic dipole anomaly on mean summer evident (2001–2009) enhances area export at Fram Strait....
Abstract The Arctic icescape is rapidly transforming from a thicker multiyear ice cover to thinner and largely seasonal first-year with significant consequences for primary production. One critical challenge understand how productivity will change within the next decades. Recent studies have reported extensive phytoplankton blooms beneath ponded sea during summer, indicating that satellite-based annual production estimates may be significantly underestimated. Here we present unique...
Year-round observations of the physical snow and ice properties processes that govern pack evolution its interaction with atmosphere ocean were conducted during Multidisciplinary drifting Observatory for Study Arctic Climate (MOSAiC) expedition research vessel Polarstern in Ocean from October 2019 to September 2020. This work was embedded into interdisciplinary design 5 MOSAiC teams, studying atmosphere, sea ice, ocean, ecosystem, biogeochemical processes. The overall aim characterize cover...
Arctic Ocean properties and processes are highly relevant to the regional global coupled climate system, yet still scarcely observed, especially in winter. Team OCEAN conducted a full year of physical oceanography observations as part Multidisciplinary drifting Observatory for Study Climate (MOSAiC), drift with sea ice from October 2019 September 2020. An international team designed implemented program characterize system unprecedented detail, seafloor air-sea ice-ocean interface,...
Abstract Sea ice monitoring by polar orbiting satellites has been developed over more than four decades and is today one of the most well-established applications space observations. This article gives an overview data product development from first sensors to state-of-the-art regarding retrieval methods, new products operational sets serving climate as well daily services including charting forecasting. Passive microwave longest history represents backbone global with already consistent...
Abstract Snow on sea ice influences the Arctic energy and heat budgets is therefore important for climate studies. Methods to derive snow depth based satellite‐borne microwave radiometer observations have existed since 1990s. However, in most widely used algorithm can only be applied over first‐year (FYI) does not make use of lower frequencies, which are available 2002. Here we present three improvements current passive retrieval: (a) We new coefficients a regression analysis using 5 years...
Satellite‐based estimates of monthly sea ice volume exports through Fram Strait for the years 2003 to 2008 are presented. These obtained from individual satellite observations thickness, area, and drift. First, freeboard is inferred ICESat laser altimeter then converted thickness estimates. Sea area drift derived AMSR‐E 89 GHz data. Retrieved compare within 0.5 m with few ULS data available in Strait. The mean, minimum, maximum observed export amounts 217, 92, 420 km 3 /month, respectively....
Abstract Arctic sea ice has displayed significant thinning as well an increase in drift speed recent years. Taken together this suggests associated rise deformation rate. A winter and spring expedition to the covered region north of Svalbard–the Norwegian young ICE2015 (N‐ICE2015)—gave opportunity deploy extensive buoy arrays monitor first‐year second‐year now common majority Basin. During 5 month long expedition, cover underwent several strong events, including a powerful storm early...
Abstract The Arctic sea ice cover is rapidly shrinking, but a direct, longer‐term assessment of the thinning remains challenging. A new time series constructed from in situ measurements thickness at end melt season Fram Strait shows by over 50% during 2003–2012. modal and mean along 79°N decreased rate 0.3 0.2 m yr −1 , respectively, with long‐term averages 2.5 3 m. Airborne observations reveal an east‐west gradient across strait spring not summer due to advection more different source...
A large retreat of sea-ice in the 'stormy' Atlantic Sector Arctic Ocean has become evident through a series record minima for winter maximum extent since 2015. Results from Norwegian young sea ICE (N-ICE2015) expedition, five-month-long (Jan-Jun) drifting ice station first and second year pack-ice north Svalbard, showcase how this region is frequently affected by passing storms. Here we synthesise interdisciplinary N-ICE2015 dataset, including independent observations atmosphere, snow,...
During two consecutive cruises to the Eastern Central Arctic in late summer 2012, we observed floating algal aggregates melt-water layer below and between melting ice floes of first-year pack ice. The macroscopic (1-15 cm diameter) had a mucous consistency were dominated by typical ice-associated pennate diatoms embedded within matrix. Aggregates maintained buoyancy accumulated just above strong pycnocline that separated meltwater seawater layers. We able, for first time, obtain quantitative...
Scientists embarked on a 6-month expedition in the Arctic Ocean to study thinning sea ice cover, improve our understanding of loss effects, and help predict future changes.
ABSTRACT The presence of leads with open water or thin ice is an important feature the Arctic sea cover. Leads regulate heat, gas and moisture fluxes between ocean atmosphere are areas high growth rates during periods freezing conditions. Here, algorithm providing automatic lead detection based on synthetic aperture radar images described that can be applied to a wide range Sentinel-1 scenes. By using both HH HV channels instead single co-polarised observations able classify more correctly....
Abstract The Fram Strait sea ice volume export 1992–2014 is derived by combining thickness from upward looking sonars (ULS) with satellite observations of drift and area. the main gate for Arctic. average yearly 2,400 ± 640 km 3 . mean modal ULS in decreased 15% 21% per decade, respectively, during 1990–2014. Combined area this leads to a decrease Arctic 27 2% decade between 1992 2014. Thus, given time period, changes do not drive Basin. However, individual years like 2007 2012 likely has...
We examine an extensive synthetic aperture radar (SAR) data set from the Arctic Ocean spanning a time period January to June 2015, with aim of identifying multi-polarization parameters that can be used accurately separate newly formed sea ice surroundings. Newly areas both provide favourable routing for ship traffic, and are key climate science because they enable heat exchange between ocean atmosphere. Our encompasses three different frequencies, X-, C- L-band, at range incidence angles,...
The Southern Ocean is disproportionately important in its effect on the Earth system, impacting climatic, biogeochemical and ecological systems, which makes recent observed changes to this system cause for global concern. enhanced understanding improvements predictive skill needed projecting future states of require sustained observations. Over last decade, Observing System (SOOS) has established networks enhancing regional coordination research community groups advance development observing...
Satellite-borne synthetic aperture radar has proven to be a valuable tool for sea ice monitoring more than two decades. In this study, we examine the performance of an automated classification algorithm based on polarimetric TerraSAR-X images. first step our approach, extract 12 features from HH-VV dualpol StripMap second step, train artificial neural network, and then, feed feature vectors into trained network classify each pixel type. The part analysis addresses predictive value different...
Abstract. We combine satellite data products to provide a first and general overview of the physical sea ice conditions along drift international Multidisciplinary drifting Observatory for Study Arctic Climate (MOSAiC) expedition comparison with previous years (2005–2006 2018–2019). find that MOSAiC was around 20 % faster than climatological mean drift, as consequence large-scale low-pressure anomalies prevailing Barents–Kara–Laptev region between January March. In winter (October–April),...
Specially equipped aircraft will follow air masses into and out of the Arctic, observing their transformations improving our knowledge Arctic climate its global influence.
Abstract Melt ponds forming on Arctic sea ice in summer significantly reduce the surface albedo and impact heat mass balance of ice. Therefore, their areal coverage, which can undergo rapid change, is crucial to monitor. We present a revised method extract melt pond fraction (MPF) from Sentinel‐2 satellite imagery, evaluated by MPF products higher‐resolution helicopter‐borne imagery. The analysis evolution during MOSAiC campaign 2020, shows split Central Observatory (CO) into level highly...