A5014068393- Oceanographic and Atmospheric Processes
- Marine and coastal ecosystems
- Marine Biology and Ecology Research
- Ocean Waves and Remote Sensing
- Climate variability and models
- Marine and fisheries research
- Atmospheric and Environmental Gas Dynamics
- Isotope Analysis in Ecology
- Tropical and Extratropical Cyclones Research
- Ocean Acidification Effects and Responses
- Geology and Paleoclimatology Research
- Coastal and Marine Management
- Microbial Community Ecology and Physiology
- Methane Hydrates and Related Phenomena
- Meteorological Phenomena and Simulations
- Reservoir Engineering and Simulation Methods
- Geophysics and Gravity Measurements
- Marine and environmental studies
- Cruise Tourism Development and Management
- International Maritime Law Issues
- Cardiovascular and Diving-Related Complications
- Global Energy and Sustainability Research
- Geochemistry and Geologic Mapping
- Marine Bivalve and Aquaculture Studies
- Solar and Space Plasma Dynamics
GEOMAR Helmholtz Centre for Ocean Research Kiel
2014-2024
Max Planck Institute for Meteorology
2022-2023
Humboldt-Universität zu Berlin
2018
Kiel University
2015
Abstract. State-of-the-art Earth system models typically employ grid spacings of O(100 km), which is too coarse to explicitly resolve main drivers the flow energy and matter across system. In this paper, we present new ICON-Sapphire model configuration, targets a representation components their interactions with spacing 10 km finer. Through use selected simulation examples, demonstrate that can (i) be run coupled globally on seasonal timescales 5 km, monthly 2.5 daily 1.25 km; (ii) large...
Abstract. Here we present first observations, from instrumentation installed on moorings and a float, of unexpectedly low (<2 μmol kg−1) oxygen environments in the open waters tropical North Atlantic, region where concentration does normally not fall much below 40 kg−1. The low-oxygen zones are created at shallow depth, just mixed layer, euphotic zone cyclonic eddies anticyclonic-modewater eddies. Both types prone to high surface productivity. Net respiration rates for found be 3 5 times...
Abstract. Coherent mesoscale features (referred to here as eddies) in the tropical northeastern Atlantic Ocean (between 12–22° N and 15–26° W) are examined characterized. The eddies' surface signatures investigated using 19 years of satellite-derived sea level anomaly (SLA) data. Two automated detection methods applied, geometrical method based on closed streamlines around eddy cores, Okubo–Weiß relation between vorticity strain. Both give similar results. Mean SLA, temperature (SST)...
Subsurface eddies are known features of ocean circulation, but the sparsity observations prevents an assessment their importance for biogeochemistry. Here we use a global eddying (0.1°) ocean‐biogeochemical model to carry out census subsurface coherent originating from eastern boundary upwelling systems (EBUS) and quantify biogeochemical effects as they propagate westward into subtropical gyres. While most exist few months, moving over distances hundreds kilometers, small fraction (<5%)...
Abstract The region encompassing the Kuroshio Extension (KE) in Northwestern Pacific Ocean (25°N–45°N and 130°E–180°E) is one of most eddy‐energetic regions global ocean. three‐dimensional structures transports mesoscale eddies this are comprehensively investigated by combined use satellite data Argo profiles. With allocation profiles inside detected eddies, spatial variations eddy temperature salinity anomalies analyzed. results show that predominantly have subsurface (near‐surface)...
Abstract. The eastern tropical North Atlantic (ETNA) features a mesopelagic oxygen minimum zone (OMZ) at approximately 300–600 m depth. Here, concentrations rarely fall below 40 µmol O2 kg−1, but are expected to decline under future projections of global warming. recent discovery mesoscale eddies that harbour shallow suboxic (< 5 kg−1) OMZ just the mixed layer could serve identify zooplankton groups may be negatively or positively affected by ongoing ocean deoxygenation. In spring 2014,...
Zooplankton organisms are a central part of pelagic ecosystems. They feed on all kinds particulate matter and their egested fecal pellets contribute substantially to the passive sinking flux depth. Some zooplankton species also conduct diel vertical migrations (DVMs) between surface layer (where they at nighttime) midwater depth hide daytime from predation). These DVMs cause active export organic inorganic as excrete, defecate, respire, die preyed upon In Eastern Tropical North Atlantic...
Abstract. The temporal evolution of the physical and biogeochemical structure an oxygen-depleted anticyclonic modewater eddy is investigated over a 2-month period using high-resolution glider ship data. A weakly stratified core (squared buoyancy frequency N2 ∼ 0.1 × 10−4 s−2) at shallow depth identified with horizontal extent about 70 km bounded by maxima in N2. upper maximum (3–5 coincides mixed layer base lower (0.4 found 200 m centre. shows constant slope temperature/salinity (T∕S)...
Abstract. Ocean general circulation models still have large upper-ocean biases, including in tropical sea surface temperature, that are possibly connected to the representation of vertical mixing. In earlier studies, ocean mixing parameterization has usually been tuned for a specific site or only within model. We present here systematic comparison effects changes scheme two different global models, ICON-O and FESOM, run at horizontal resolution 10 km Atlantic. test commonly used schemes:...
Submesoscale coherent vortices (SCVs) have been frequently observed in the eastern tropical Atlantic (between 12&#176;S and 12&#176;N) based on moored shipboard observations. They are located well below mixed layer with no surface signature and, thus, undetectable by remote sensing making in-situ observations modeling indispensable. The SCVs persist relatively long-lived coherent, despite increasing suppression of geostrophic balance rapid change Coriolis parameter...
Abstract. Localized open-ocean low-oxygen “dead zones” in the eastern tropical North Atlantic are recently discovered ocean features that can develop dynamically isolated water masses within cyclonic eddies (CE) and anticyclonic mode-water (ACME). Analysis of a comprehensive oxygen dataset obtained from gliders, moorings, research vessels Argo floats reveals “dead-zone” found surprisingly high numbers large area about 4 to 22° N, shelf at boundary 38° W. In total, 173 profiles with...
Abstract Gelatinous zooplankton hold key functions in the ocean and have been shown to significantly influence transport of organic carbon deep sea. We discovered a gelatinous, flux‐feeding polychaete genus Poeobius very high abundances mesoscale eddy tropical Atlantic Ocean, where it co‐occurred with extremely low particle concentrations. Subsequent analysis an extensive situ imaging dataset revealed that sp. occurred sporadically between 5°S–20°N 16°W–46°W upper 1000 m. Abundances were...
Abstract. State-of-the-art Earth System models typically employ grid spacings of O(100 km), too coarse to explicitly resolve main drivers the flow energy and matter across System. In this paper, we present new ICON-Sapphire model configuration, which targets a representation components their interactions with spacing 10 km finer. Through use selected simulation examples, demonstrate that can already now (i) be run coupled globally on seasonal time scales 5 monthly 2.5 km, (ii) large eddies...
Based on a combination of over 20 years satellite data with extensive in situ measurements from previous research expeditions, an initial step is taken to differentiate the impact submesoscale processes and turbulent mixing Eastern Boundary Upwelling System (EBUS) off Senegal Mauritania. EBUS are essential part global carbon cycle central importance for sustainability economic food resources. In tropical Senegalo-Mauritanian EBUS, sea surface temperatures net primary production exhibits...
Continuous high-resolution underway measurements of dimethyl sulfide (DMS) and isoprene in the ocean surface were conducted from Germany to South Africa November 2008. DMS, total dimethylsulfoniopropionate (DMSPt), 19′-hexanoyloxyfucoxanthin (19′-hex) correlated nitrogen-depleted regions when they clustered by nitrogen phosphorous ratio (N:P). The 19′-hex-containing algae groups might be a common source DMSPt, low N:P regions. Additionally, DMS nitrate-depleted against nitrate...
Abstract. The eastern tropical North Atlantic (ETNA) is characterized by a highly productive coastal upwelling system and moderate oxygen minimum zone with lowest open-ocean (O2) concentrations of approximately 40 μmol kg−1. recent discovery re-occurring mesoscale eddies close to anoxic O2 (< 1 kg−1) located just below the mixed layer has challenged our understanding distribution biogeochemical processes in this area. Here, we present first microbial community study from deoxygenated...
Abstract. The occurrence of mesoscale eddies that develop suboxic environments at shallow depth (about 40–100 m) has recently been reported for the eastern tropical North Atlantic (ETNA). Their hydrographic structure suggests water mass inside eddy is well isolated from ambient waters supporting development severe near-surface oxygen deficits. So far, and biogeochemical characterization these was limited to a few autonomous surveys, with use moorings, underwater gliders profiling floats. In...
Abstract. The influence of mesoscale eddies on the flow field and water masses, especially oxygen distribution eastern tropical South Pacific, is investigated from a mooring, float, satellite data set. Two anticyclonic (ACE1/2), one mode-water (MWE), cyclonic eddy (CE) are identified followed in detail with their westward transition velocities 3.2 to 6.0 cm s−1 generation region, shelf Peruvian Chilean upwelling regime, across Stratus Ocean Reference Station (ORS; ∼20∘ S, 85∘ W) decaying...
Major uncertainties in air-sea gas flux parameterizations may arise from a yet unpredictable sea surface microlayer (SML). Its influence on exchange is twofold as organic matter, particular surfactants, one side and organisms enriched the SML other can alter fluxes. However, spatial heterogeneity of its potential consequences for are not well understood. This study examines SML’s surfactant pool dynamics microbial enrichment across sharp hydrological front newly upwelled filament off...
Abstract. The northwestern Tropical Atlantic Ocean is a turbulent region, filled with mesoscale eddies and regional currents. In this intense dynamical context, several water masses thermohaline characteristics of different origins are advected, mixed, stirred at the surface depth. EUREC4A-OA/ATOMIC experiment that took place in January February 2020 was dedicated to assessing processes play especially interaction between ocean atmosphere. For reason, four oceanographic vessels autonomous...
Abstract The direct response of the tropical mixed layer to near-inertial waves (NIWs) has only rarely been observed. Here, we present upper-ocean turbulence data that provide evidence for a strongly elevated vertical diffusive heat flux across base in presence NIW, thereby cooling at rate 244 W m −2 over 20 h continuous measurements. We investigate seasonal cycle strong NIW events and find despite their local intermittent nature, they occur preferentially during boreal summer, presumably...
Abstract. Ocean General Circulation Models still have large upper-ocean biases e.g. in tropical sea surface temperature, possibly connected to the representation of vertical mixing. In earlier studies, ocean mixing parameterisation has usually been tuned for a specific site or only within model. We present here systematic comparison effects changes scheme two different global models, ICON-O and FESOM, run at horizontal resolution 10 km Atlantic. test commonly used schemes; K-Profile...
Abstract. Coherent mesoscale features (referred to here as eddies) in the tropical northeast Atlantic (between 12–22° N and 15–26° W) are examined characterised. The eddies' surface signatures investigated using 19 years of satellite derived sea level anomaly (SLA) data. Two automated detection methods applied, geometrical method based on closed streamlines around eddy cores, Okubo–Weiß relation between vorticity strain. Both give similar results. Mean SLA, temperature (SST) salinity (SSS)...
Abstract. The physical (temperature, salinity, velocity) and biogeochemical (oxygen, nitrate) structure of an oxygen depleted coherent, baroclinic, anticyclonic mode-water eddy (ACME) is investigated using high-resolution autonomous glider ship data. A distinct core with a diameter about 70 km found in the eddy, extending from 60 to 200 m depth and. occupied by fresh cold water low high nitrate concentrations, bordered local maxima buoyancy frequency. Velocity property gradient sections show...
Abstract. Localized open-ocean low–oxygen dead-zones in the tropical Northeast Atlantic are recently discovered ocean features that can develop dynamically isolated water masses within cyclonic eddies (CE) and anticyclonic modewater (ACME). Analysis of a comprehensive oxygen dataset obtained from gliders, moorings, research vessels Argo floats revealed with low concentrations at 50–150 m depths be found surprisingly high numbers large area (from about 4°N to 22°N, shelf eastern boundary...