A5077322642- Arctic and Antarctic ice dynamics
- Climate variability and models
- Oceanographic and Atmospheric Processes
- Cryospheric studies and observations
- Methane Hydrates and Related Phenomena
- Geology and Paleoclimatology Research
- Climate change and permafrost
- Geological Studies and Exploration
- Atmospheric and Environmental Gas Dynamics
- Meteorological Phenomena and Simulations
- Marine and coastal ecosystems
- Arctic and Russian Policy Studies
- Marine and environmental studies
- Hydrocarbon exploration and reservoir analysis
- Food Industry and Aquatic Biology
- Geological and Geophysical Studies
- Coastal and Marine Management
- Ocean Acidification Effects and Responses
- Geophysics and Gravity Measurements
- Underwater Acoustics Research
- Tropical and Extratropical Cyclones Research
- Polar Research and Ecology
- demographic modeling and climate adaptation
- Scientific Research and Discoveries
- Global Energy and Sustainability Research
GEOMAR Helmholtz Centre for Ocean Research Kiel
2012-2025
GEOMAR Technologie GmbH - GTG
2023
Johns Hopkins University Applied Physics Laboratory
2013-2015
University of Washington
2012-2015
Seattle University
2014
Ajanta Pharma (India)
2013
Princeton University
2010
NOAA Geophysical Fluid Dynamics Laboratory
2008
Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung
1999-2007
RTX (United States)
1999
A numerical ocean sea-ice model is used to demonstrate that Arctic sea ice retreat affects momentum transfer into the ocean. thinner and thus weaker cover more easily forced by wind, which increases flux. In contrast, increasing open water reduces because surface provides greater drag than surface. We introduce concept of optimal concentration: with concentration up a point, beyond frictional losses floe interaction damp transfer. For common internal stress formulation, 80–90% yields...
Abstract Evidence is presented for the notion that some contribution to recent decadal trends observed in Southern Hemisphere, including lack of a strong Ocean surface warming, may have originated from longer-term internal centennial variability originating Ocean. The existence such supported by instrumental sea temperatures (SSTs), multimillennial reconstruction Tasmanian summer tree rings, and millennial control integration Kiel Climate Model (KCM). model was previously shown be linked...
Abstract Arctic sea ice mediates atmosphere-ocean momentum transfer, which drives upper ocean circulation. How Ocean surface stress and velocity respond to decline changing winds under global warming is unclear. Here we show that state-of-the-art climate models consistently predict an increase in future (2015–2100) response increased wind speed, declining area, a weaker pack. While speeds most during fall (+2.2% per decade), rises winter (+5.1% decade) being amplified by reduced internal...
Abstract The Arctic sea ice cover is thinning and retreating, causing changes in surface roughness that turn modify the momentum flux from atmosphere through into ocean. New model simulations comprising variable drag coefficients for both air water interface demonstrate heterogeneity significantly impacts spatial distribution trends of ocean stress during last decades. Simulations with constant as used most climate models show an increase annual mean (0.003 N/m 2 per decade, 4.6%) due to...
Abstract Deep convection and associated deep water formation are key processes for climate variability, since they impact the oceanic uptake of heat trace gases alter structure strength global overturning circulation. For long, in subpolar North Atlantic was thought to be confined central Labrador Sea western gyre (SPG). However, there is increasing observational evidence that also has occurred eastern SPG south Cape Farewell Irminger Sea, particular, 2015–2018. Here we assess this recent...
Abstract. A hierarchy of global 1/4∘ (ORCA025) and Atlantic Ocean 1/20∘ nested (VIKING20X) ocean–sea-ice models is described. It shown that the eddy-rich configurations performed in hindcasts past 50–60 years under CORE JRA55-do atmospheric forcings realistically simulate large-scale horizontal circulation, distribution mesoscale, overflow convective processes, representation regional current systems North South Atlantic. The Meridional Overturning Circulation (AMOC), particular long-term...
Abstract Warming of the North Atlantic region in climate history often was associated with massive melting Greenland Ice Sheet. To identify meltwater's impacts and isolate these from internal variability other global warming factors, we run single‐forcing simulations including small ensembles using three complex models differing only their ocean components. In 200‐year‐long preindustrial simulations, robust consequences abruptly increasing runoff by 0.05 Sv: sea level rise 44 ± 10 cm,...
Abstract. Observations of the eastern subpolar North Atlantic in 2010s show exceptional freshening and cooling upper ocean, peaking 2016 with lowest salinities recorded for 120 years. Published theories mechanisms driving include: reduced transport saltier, warmer surface waters northwards from subtropics associated meridional overturning; shifts pathways fresher, cooler water Labrador Sea driven by changing patterns wind stress; eastward expansion gyre. Using output a high-resolution...
Abstract. Increasing Greenland Ice Sheet melting is anticipated to impact water mass transformation in the subpolar North Atlantic and ultimately meridional overturning circulation. Complex ocean climate models are widely applied estimate magnitude timing of related impacts under global warming. We discuss role mean state, transformation, mesoscale eddies, atmospheric coupling shaping response Ocean enhanced runoff. In a suite eight dedicated 60- 100-year-long model experiments with without...
Abstract. As the climate warms, grounded ice sheet and floating shelves surrounding Antarctica are melting releasing additional freshwater into Southern Ocean. Nonetheless, almost all existing coupled models have fixed sheets lack physics required to represent dominant sources of Antarctic melt. These missing dynamics a key uncertainty that is typically unaccounted for in current global change projections. Previous modelling studies imposed meltwater demonstrated regional impacts on Ocean...
Abstract The impact of a subgrid‐scale ice thickness distribution (ITD) and two standard strength formulations on simulated Arctic sea climate is investigated. To this end, different model configurations with without an ITD were tuned by minimizing the weighted mean error between observed concentration, thickness, drift speed semiautomatic parameter optimization routine. parameterization lead to larger errors when compared simple single‐category based thickness. Interestingly, simpler...
Abstract. A new Earth system model, the Flexible Ocean and Climate Infrastructure (FOCI), is introduced. first version of FOCI consists a global high-top atmosphere (European Centre Hamburg general circulation model; ECHAM6.3) an ocean model (Nucleus for European Modelling v3.6; NEMO3.6) as well sea-ice (Louvain-la-Neuve sea Ice Model 2; LIM2) land surface components (Jena Scheme Biosphere Atmosphere Coupling in Hamburg; JSBACH), which are coupled through OASIS3-MCT software package....
Abstract Simulations with a free‐running coupled climate model show that heat release associated Southern Ocean deep convection variability can drive centennial‐scale Antarctic temperature variations of up to 2.0°C. The mechanism involves three steps: Preconditioning : accumulates at depth in the Ocean; Convection onset wind and/or sea ice changes tip buoyantly unstable system into convective state; and warming fast ice‐albedo feedbacks (on annual‐decadal time scales) slow frontal surface...
Abstract We investigate the individual and joint decadal variability of Southern Ocean state quantities, such as strength Ross Weddell Gyres, Drake Passage transport, sea ice area, using National Institute Water Atmospheric Research UK Chemistry Aerosols (NIWA‐UKCA) model CMIP5 models. Variability in these quantities is stimulated by strong deep reaching convective events Ocean, which produce an Antarctic Bottom Water‐like water mass affect large‐scale meridional density structure Ocean. An...
The loss of Arctic sea ice is a conspicuous example climate change. Climate models project ice-free conditions during summer this century under realistic emission scenarios, reflecting the increase in seasonality cover. To quantify increased Arctic-Subarctic system, we define non-dimensional number for extent, area, and volume from satellite data coupled models. We show that Arctic-Subarctic, i.e. northern hemisphere, now exhibits similar levels to Antarctic, which seasonal regime without...
Marine Heatwaves (MHWs) are ocean extreme events, characterized by anomalously high temperatures, which can have significant ecological impacts. The Northeast U.S. continental shelf is of great economical importance as it home to a highly productive ecosystem. Local warming rates exceed the global average and region experienced multiple MHWs in last decade with severe consequences for regional fisheries. Due lack subsurface observations, depth-extent not well-known, hampers assessment...
Abstract. As the climate warms, grounded ice sheet and floating shelves surrounding Antarctica are losing mass at an increasing rate injecting resulting meltwater into Southern Ocean. This freshwater input could feed back onto change, particularly since Ocean is a key contributor to global heat carbon uptake. Nonetheless, almost all existing coupled models have fixed sheets, lack physics required represent dominant sources of Antarctic melt. These missing dynamics uncertainty that...
Abstract The additional water from the Antarctic ice sheet and shelves due to climate‐induced melt can impact ocean circulation global climate. However, major processes driving are not adequately represented in Coupled Model Intercomparison Project phase 6 (CMIP6) models. Here, we analyze a novel multi‐model ensemble of CMIP6 models with consistent meltwater addition examine robustness modeled response meltwater, which has been possible previous single‐model studies. induces substantial...
Drift is a prominent parameter characterizing the Arctic sea ice cover that has deep impact on climate system. Hence it key issue to both remote sensing as well modeling community, provide reliable drift fields. This study focuses comparison of results from different ice‐ocean coupled models and validation with observational data in period 1979–2001. The all take part Ocean Model Intercomparison Project (AOMIP) observations are mainly based satellite imagery. According speed distributions,...
Abstract Global climate models exhibit large biases in the Southern Ocean. For example, Antarctic bottom water is formed mostly through open‐ocean deep convection rather than shelf convection. Still, timescale, region, and intensity of deep‐convection variability vary widely among models. We investigate physical controls this Atlantic sector Ocean, where most simulate recurring events. analyzed output from 11 exemplary CMIP5 four versions Kiel Climate Model. Of several potential control...
Abstract Freshwater input from Greenland ice sheet melt has been increasing in the past decades warming temperatures. To identify impacts enhanced meltwater into subpolar North Atlantic 1997 to 2021, we use output two nearly identical simulations eddy‐rich model VIKING20X (1/20°) only differing freshwater Greenland: one with realistic interannually varying runoff early 2000s and other climatologically (1961–2000) continued runoff. The majority of additional remains within boundary current...
Large‐scale sea‐ice thickness and surface property data were obtained in three summers different regimes the Arctic Trans‐Polar Drift (TPD) by means of helicopter electromagnetic sounding. Distribution functions P height, spacing, density sails analyzed to characterize ice ages deformations. Results suggest that modal is affected age a regime degree deformation represented shape . Mean changes with both deformation. Standard error calculations showed representative mean could be transect...