A5015216269- Oceanographic and Atmospheric Processes
- Marine and coastal ecosystems
- Maritime Navigation and Safety
- Underwater Vehicles and Communication Systems
- Marine Biology and Ecology Research
- Climate variability and models
- Ocean Acidification Effects and Responses
- Seismic Imaging and Inversion Techniques
- Marine and fisheries research
- Atmospheric and Environmental Gas Dynamics
- Reservoir Engineering and Simulation Methods
- Methane Hydrates and Related Phenomena
- Geology and Paleoclimatology Research
- Ionosphere and magnetosphere dynamics
- Arctic and Antarctic ice dynamics
- Spacecraft Design and Technology
- Geological and Geophysical Studies
- Spacecraft and Cryogenic Technologies
- Ocean Waves and Remote Sensing
- Microbial Community Ecology and Physiology
- Geological formations and processes
- Meteorological Phenomena and Simulations
- Hydrocarbon exploration and reservoir analysis
- Seismic Waves and Analysis
- Underwater Acoustics Research
GEOMAR Helmholtz Centre for Ocean Research Kiel
2016-2025
Helmholtz-Zentrum Hereon
2019
Leibniz Institute for Neurobiology
2011
Kiel University
1998-2009
Lamont-Doherty Earth Observatory
1998-2003
Columbia University
1998-2003
Abstract. Ocean observations are analysed in the framework of Collaborative Research Center 754 (SFB 754) "Climate-Biogeochemistry Interactions Tropical Ocean" to study (1) structure tropical oxygen minimum zones (OMZs), (2) processes that contribute budget, and (3) long-term changes distribution. The OMZ eastern North Atlantic (ETNA), located between well-ventilated subtropical gyre equatorial maximum, is composed a deep at about 400 m depth with its core region centred 20° W, 10° N shallow...
The OceanGliders program started in 2016 to support active coordination and enhancement of global glider activity. contributes the international efforts Global Ocean Observation System (GOOS) for Climate, Health, Operational Services. It brings together marine scientists engineers operating gliders around world: (1) observe long-term physical, biogeochemical, biological ocean processes phenomena that are relevant societal applications; and, (2) contribute GOOS through real-time delayed mode...
Abstract The formation of a subsurface anticyclonic eddy in the Peru‐Chile Undercurrent (PCUC) January and February 2013 is investigated using multiplatform four‐dimensional observational approach. Research vessel, multiple glider, mooring‐based measurements were conducted Peruvian upwelling regime near 12°30'S. data set consists >10,000 glider profiles repeated vessel‐based hydrography velocity transects. It allows detailed description its impact on near‐coastal salinity, oxygen,...
Eastern boundary upwelling systems are hotspots of marine life and primary production. The strength seasonality in these usually related to local wind forcing. However, some tropical systems, seasonal maxima productivity occur when favorable winds weak. Here, we show that the Angolan system (tAUS), maximum is due combined effect coastal trapped waves (CTWs) elevated tidal mixing on shelf. During austral winter, passage an CTW displaces nitracline upward by more than 50 m. Thereby,...
Numerical experiments are performed to examine the causes of variability Atlantic Ocean SST during period covered by National Centers for Environmental Prediction–National Center Atmospheric Research (NCEP–NCAR) reanalysis (1958–98). Three ocean models used. Two mixed layer models: one with a 75-m-deep and other variable depth layer. For both heat transports assumed remain at their diagnosed climatological values. The third model is full dynamical general circulation (GCM). All coupled...
The response of the Atlantic Ocean to North Oscillation (NAO)‐like wind forcing was investigated using an ocean‐only general circulation model coupled atmospheric boundary layer model. A series idealized experiments performed investigate interannual multi‐decadal frequency ocean a winter anomaly pattern. Overall, strength SST increased slightly with longer periods. In subpolar gyre, however, showed broad maximum in decadal band (12–16 years).
Abstract Changes in the ventilation of oxygen minimum zone (OMZ) tropical North Atlantic are studied using oceanographic data from 18 research cruises carried out between 28.5° and 23°W during 1999–2008 as well historical referring to period 1972–85. In core OMZ at about 400-m depth, a highly significant decrease 15 μmol kg−1 is found two periods. During same time interval, salinity increased by 0.1. Above OMZ, within central water layer, decreased too, but changed only slightly or even...
The time response behavior of Aanderaa optodes model 3830, 4330, and 4330F, as well a Sea‐Bird SBE63 optode JFE Alec Co. Rinko dissolved oxygen sensor was analyzed both in the laboratory field. main factor for is dynamic regime, i.e., water flow around that influences boundary layer's dynamics. Response times can be drastically reduced if sensors are pumped. Laboratory experiments under different conditions showed close to linear relation between temperature. Application diffusion including...
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. A strong El Niño developed in early 2015. Measurements from a research cruise on the R/V Sonne October 2015 near Equator east of Galapagos Islands and off shelf Peru are used to investigate changes related upper ocean comparison with earlier cruises this region. At at 85°30′ W, clear temperature increase leading lower densities 350 m had 2015, despite concurrent salinity 40 m. Lower nutrient concentrations were also present 200 m, higher oxygen observed between 130 In equatorial...
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...
Recently seismic reflection methods have been successfully applied to oceanographic issues. Here, we present a new approach, combining XBT and CTD surveys with observations, visualize long sections resolution down few meters. The challenge full investigation of mixing processes has the tremendous span spatial scales ranging from hundreds kilometers centimeters. Traditional hydrographic observations could only resolve large scale effects by measuring temperature salinity profiles at discrete...
Abstract The Peruvian upwelling system encompasses the most intense and shallowest oxygen minimum zone (OMZ) in ocean. This shows pronounced submesoscale activity like filaments fronts. We carried out glider‐based observations off Peru during austral summer 2013 to investigate whether frontal processes ventilate OMZ. present observational evidence for subduction of highly oxygenated surface water a cold filament. event ventilates oxycline but does not reach OMZ core waters. In regional...
The deep water of the western Mediterranean Sea is known to have become warmer and saltier since about 1950s. causes these changes have, however, not yet been sactisfactorily determined. Previous studies speculated on decreasing precipitation, greenhouse warming and/or anthropogenic reduction freshwater flux into eastern Mediterranean. Here we report results from a new oceanographic database together with determinations longterm fresh budget. We analyzed temperature salinity data past 40...
Equatorial deep jets (EDJs) are a prominent flow feature of the equatorial Atlantic below Undercurrent down to about 3000 m. Here we analyze long‐term moored velocity and oxygen observations, as well shipboard hydrographic current sections acquired along 23°W covering depth range minimum zones eastern tropical North South Atlantic. The zonal data show high‐baroclinic mode EDJ oscillations at period 4.5 years. observations which do not resolve or cover full 4.5‐yr cycle nevertheless reveal...
Abstract. The replenishment of consumed oxygen in the open ocean minimum zone (OMZ) off northwest Africa is accomplished by transport across and along density surfaces, i.e. diapycnal isopycnal supply. Here supply investigated using a large observational set profiles mixing data from years 2008 to 2010. Diapycnal inferred different sources: (i) large-scale tracer release experiment, (ii) microstructure profiles, (iii) shipboard acoustic current measurements plus profiles. From these...
Abstract The turbulent dissipation rate ε is a key parameter to many oceanographic processes. Recently, gliders have been increasingly used as carrier for microstructure sensors. Compared conventional ship-based methods, glider-based observations allow long-duration measurements under adverse weather conditions and at lower costs. incident water velocity U an input the calculation of rate. Since cannot be measured using standard glider sensor setup, normally computed from steady-state flight...
Energy levels of internal waves are estimated from seismic reflection data. Three legacy sections 1993 and 1997 obtained off the Iberian Peninsula have been analyzed for acoustic reflections within water column. The aligned continuously up to several kilometers over large parts in depth interval 200 2000 m. Depth variations these thought be caused by background wave field. From we derive horizontal number spectra normalized displacement. general slope power density is remarkably consistent...