A5087171675- Oceanographic and Atmospheric Processes
- Arctic and Antarctic ice dynamics
- Geology and Paleoclimatology Research
- Climate variability and models
- Methane Hydrates and Related Phenomena
- Maritime Navigation and Safety
- Marine and coastal ecosystems
- Arctic and Russian Policy Studies
- Tropical and Extratropical Cyclones Research
- Geological Studies and Exploration
- Atmospheric and Environmental Gas Dynamics
- Marine and environmental studies
- Climate change and permafrost
- Ocean Waves and Remote Sensing
- Environmental Monitoring and Data Management
- Offshore Engineering and Technologies
- Hydrology and Watershed Management Studies
- Geological formations and processes
- Aquatic and Environmental Studies
- Underwater Acoustics Research
- Geophysics and Gravity Measurements
- Meteorological Phenomena and Simulations
- Coastal and Marine Dynamics
- Underwater Vehicles and Communication Systems
- Marine and fisheries research
Federal Maritime and Hydrographic Agency of Germany
2019-2024
Universität Hamburg
2012-2020
University of Bremen
2010
The Denmark Strait overflow provides about half of the total dense water from Nordic Seas into North Atlantic Ocean. velocity has been monitored in with two moored Acoustic Doppler Current Profilers since 1996 several interruptions due to mooring losses or instrument failure. So far, transports were only calculated when data both moorings available. In this work, we introduce a linear model fill gaps time series one is mean transport 3.4 Sv and exhibits variance 2.0 2 . No significant trend...
Abstract. The Arctic Mediterranean (AM) is the collective name for Ocean, Nordic Seas, and their adjacent shelf seas. Water enters into this region through Bering Strait (Pacific inflow) passages across Greenland–Scotland Ridge (Atlantic modified within AM. waters leave AM in several flow branches which are grouped two different categories: (1) overflow of dense water deep Ridge, (2) outflow light – here termed surface on both sides Greenland. These exchanges transport heat salt out...
Abstract. From 1994 to 2011, instruments measuring ocean currents (Acoustic Doppler Current Profilers; ADCPs) have been moored on a section crossing the Faroe–Shetland Channel. Together with CTD (Conductivity Temperature Depth) measurements from regular research vessel occupations, they describe flow field and water mass structure in channel. Here, we use these data calculate average volume transport properties of warm through channel Atlantic towards Arctic, termed inflow. We find this be...
Abstract The major export route of dense water from the Nordic Seas into North Atlantic is in deep channel Denmark Strait. Here currents have been monitored with one or two moored Acoustic Doppler Current Profilers (ADCPs) since 1996. Volume transport estimates Strait Overflow Water (DSOW) so far were based on these data, which regressed to total a numerical model. resulting has used many publications. we present results an extended five‐mooring array deployed 2014/2015, included...
Key Points The AMOC is a system of ocean currents that move heat and carbon around the planet predicted to decline in future has been directly measured since 2000s, but we now have observation systems place can verify We look at how these might develop consider they fit an optimized Atlantic observing
Abstract Using 111 shipboard hydrographic sections across Denmark Strait occupied between 1990 and 2012, we characterize the mean conditions at sill, quantify water mass constituents, describe dominant features of Overflow Water (DSOW). The vertical temperature, salinity, density reveal presence circulation components found upstream in particular shelfbreak East Greenland Current (EGC) separated EGC. These correspond to fronts consistent with surface‐intensified southward flow. Deeper column...
Abstract Denmark Strait Overflow Water (DSOW) supplies the densest contribution to North Atlantic Deep and is monitored at several locations in subpolar Atlantic. Hydrographic (temperature salinity) velocity time series from three multiple‐mooring arrays sill, 180 km downstream (south of Dohrn Bank) a further 320 on east Greenland continental slope near Tasiilaq (formerly Angmagssalik), were analyzed quantify variability track anomalies DSOW period 2007–2012. No long‐term trends detected...
Near the western boundary of tropical North Atlantic, where Brazil Current (NBC) retroflects into Equatorial Countercurrent, large anticyclonic rings are shed. After separating from retroflection region, so‐called NBC travel northwestward along Brazilian coast, until they reach island chain Lesser Antilles and disintegrate. These contribute substantially to upper limb return flow Atlantic Meridional Overturning Circulation by carrying South Water northern subtropical gyre. Their relevance...
Abstract We examine the relative dispersion of surface drifters deployed in groups triplets at boundaries a filament upwelling region off Namibia for both entire ensemble and two main subgroups. For group released northern boundary filament, close to front, we find that mean-square pair separation 〈 s 2 ( t )〉 shows characteristic distinct regimes [nonlocal, local (Richardson), diffusive] an ocean mixed layer. confirm different by rescaled presentation moments n thereby also explain...
Abstract. The Iceland–Faroe Ridge (IFR) is considered to be the third most important passage for dense overflow water from Nordic Seas feeding into lower limb of Atlantic Meridional Overturning Circulation with a volume transport on order 1 Sv (106 m3 s−1). Western Valley, which northernmost deep across IFR, has been presumed supply strong and persistent (WV-overflow), contributing large fraction total IFR. However, prolonged measurements this are so far missing. In quantify flow by direct...
Abstract The Benguela upwelling system is one of the four strongest systems in world. Meso‐scale and submeso‐scale structures like eddies filaments build up at front between cold upwelled water warm surface offshore. From three a half years satellite data (MODIS) sea temperature (SST) more than 450 were identified used for extensive statistics scales, occurrence frequency location Lüderitz cell its vicinity. In situ SST, salinity profiles temperature, velocity collected during six cruises...
Abstract The descent of the Denmark Strait overflow plume is an important process in Atlantic Meridional Overturning Circulation. Downstream sill, entrains ambient water, increasing its volume transport. entrainment and related transfer energy can be driven by vertical or horizontal turbulent mixing, varies spatially, as descends, temporally, transport at sill changes. Using over 30 years profile data, this spatial temporal variability first 200 km downstream was investigated. Dissipation...
Abstract The dense outflow through Denmark Strait is the largest contributor to lower limb of Atlantic meridional overturning circulation, yet a description full velocity field across strait remains incomplete. Here we analyze set 22 shipboard hydrographic–velocity sections occupied along Látrabjarg transect at sill, obtained over time period 1993–2018. provide first complete view kinematic components sill: shelfbreak East Greenland Current (EGC), combined flow separated EGC, and North...
Abstract Just before Christmas 2023, the low-pressure system storm “Zoltan” struck Germany, resulting in widespread damage and two consecutive large surges on North Sea coast night from Thursday 21 December 2023 to Friday 22 2023. Storm Zoltan brought heavy rainfall, accompanied by thunderstorms winds ranging between 90 115 $$\mathrm {km\,h^{-1}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>km</mml:mi> <mml:mspace/> <mml:msup> <mml:mi>h</mml:mi>...
Abstract Flemish Pass, located at the western subpolar margin, is a passage (sill depth 1200 m) that constrained by Grand Banks and underwater plateau Cap. In addition to Deep Western Boundary Current (DWBC) pathway offshore of Cap, Pass represents another southward transport for two modes Labrador Sea Water (LSW), lightest component North Atlantic carried with DWBC. This avoids potential stirring regions east Cap deflection into interior Atlantic. Ship‐based velocity measurements between...
© 2017 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).CORRESPONDING AUTHOR: Dr. Chris Hewitt, chris.hewitt@metoffice.gov.uk
Abstract. Through the Faroese Channels – collective name for a system of channels linking Faroe–Shetland Channel, Wyville Thomson Basin, and Faroe Bank Channel there is deep flow cold waters from Arctic regions that exit as overflow through across Ridge. The upper layers, in contrast, are dominated by warm, saline water masses southwest, termed Atlantic water. In spite intensive research over more than century, still open questions on passage these with conflicting views recent literature....
Abstract The Denmark Strait Overflow (DSO) contributes roughly half to the total volume transport of Nordic overflows. overflow increases its by entraining ambient water as it descends into subpolar North Atlantic, feeding deep branch Atlantic Meridional Overturning Circulation. In June 2012, a multiplatform experiment was carried out in DSO plume on continental slope off Greenland (180 km downstream sill Strait), observe variability associated with entrainment waters plume. this study, we...
Abstract. From 1994 to 2011, instruments measuring ocean currents (ADCPs) have been moored on a section crossing the Faroe-Shetland Channel. Together with CTD (Conductivity Temperature Depth) measurements from regular research vessel occupations, they describe flow field and water mass structure in channel. Here, we use these data calculate average volume transport properties of warm through channel Atlantic towards Arctic, termed inflow. We find this be 2.7 ± 0.5 Sv (1 = 106 m3 s−1) between...
The transport of Upper Labrador Sea Water (ULSW) at Flemish Cap (47°N/45°W) is investigated in the period 1960–2009 using output from an 8 km resolution numerical ocean model. average model ULSW decreases southward 6.7 Sv 53°N to 4.5 45°N due interior pathways. largest fraction total volume goes around within Deep Western Boundary Current (DWBC, 72%) but a significant part through Pass (20%). At interannual timescales, variability shows distinct behavior when compared DWBC and upstream...
Abstract The Eastern Boundary Current is an essential part of the water mass exchange between subtropical and subpolar North Atlantic. Here, we study offshore branch European Shelf (ESC) over Goban Spur slope area off Ireland. Our analysis based on current measurements obtained from a multiyear mooring effort, complemented by ship‐board observations along hydrographic section, satellite‐derived estimates absolute dynamic topography with geostrophic currents, float trajectories. These data...
Abstract The Denmark Strait overflow is the major export route of dense water from Arctic Mediterranean into North Atlantic. At Strait's shallow sill, a bottom‐intensified cold and plume, bound to east by thermal front formed with warmer, northward flowing Icelandic Irminger Current. More than two decades observations at sill show strong fluctuations volume flux on daily time scales. To better understand source this variability, five‐mooring array was installed capturing nearly 1 year...