A5048381171- Oceanographic and Atmospheric Processes
- Marine and coastal ecosystems
- Climate variability and models
- Geology and Paleoclimatology Research
- Solar and Space Plasma Dynamics
- Ocean Waves and Remote Sensing
- Ocean Acidification Effects and Responses
- Atmospheric and Environmental Gas Dynamics
- Methane Hydrates and Related Phenomena
- Tropical and Extratropical Cyclones Research
- Arctic and Antarctic ice dynamics
- Solar Radiation and Photovoltaics
- Marine Biology and Ecology Research
- Geophysics and Gravity Measurements
- Marine and fisheries research
- Geological formations and processes
- Astro and Planetary Science
- Geological and Geophysical Studies
- Coastal and Marine Management
- Meteorological Phenomena and Simulations
- Geomagnetism and Paleomagnetism Studies
- Medical and Health Sciences Research
- Geological Studies and Exploration
- Marine and environmental studies
- Stellar, planetary, and galactic studies
GEOMAR Helmholtz Centre for Ocean Research Kiel
2016-2025
Kiel University
2016-2025
GEOMAR Technologie GmbH - GTG
2016-2024
Oregon State University
2023
Laboratoire d’Études en Géophysique et Océanographie Spatiales
2022
University of North Dakota
2019
Leibniz Institute for Neurobiology
2004-2011
Federal Office of Consumer Protection and Food Safety
2010
Institut für Sonnenphysik
1998-2008
Universität Hamburg
1997-2005
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...
Abstract Well-known problems trouble coupled general circulation models of the eastern Atlantic and Pacific Ocean basins. Model climates are significantly more symmetric about equator than is observed. sea surface temperatures biased warm south southeast equator, atmosphere too rainy within a band equator. Near-coastal equatorial SSTs warm, producing zonal SST gradient in opposite sign to that The U.S. Climate Variability Predictability Program (CLIVAR) Eastern Tropical Synthesis Working...
The Mauritanian coastal area is one of the most biologically productive upwelling regions in world ocean. Shipboard observations carried out during maximum season and short‐term moored are used to investigate diapycnal mixing processes quantify fluxes nutrients. indicate strong tide‐topography interactions that favored by near‐critical angles occurring on large parts continental slope. Moored velocity reveal existence highly nonlinear internal waves bores levels wave spectra strongly...
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. We propose a satellite mission that uses near-nadir Ka-band Doppler radar to measure surface currents, ice drift and ocean waves at spatial scales of 40 km more, with snapshots least every day for latitudes 75 82°, few days other latitudes. The use incidence angles 6 12° allows measurement the directional wave spectrum, which yields accurate corrections wave-induced bias in current measurements. instrument's design, an algorithm vector retrieval expected performance are presented...
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)...
Ocean surface winds, currents, and waves play a crucial role in exchanges of momentum, energy, heat, freshwater, gases, other tracers between the ocean, atmosphere, ice. Despite being strongly coupled to upper ocean circulation overlying efforts improve atmospheric, wave observations models have evolved somewhat independently. From an observational point view, community bridge this gap led proposals for satellite Doppler oceanography mission concepts, which could provide unprecedented...
Abstract Prediction and Research Moored Array in the Tropical Atlantic (PIRATA) is a multinational program initiated 1997 tropical to improve our understanding ability predict ocean‐atmosphere variability. PIRATA consists of network moored buoys providing meteorological oceanographic data transmitted real time address fundamental scientific questions as well societal needs. The maintained through dedicated yearly cruises, which allow for extensive complementary shipboard measurements provide...
The Sea surface KInematics Multiscale monitoring (SKIM) satellite mission is designed to explore ocean current and waves. This includes tropical currents, notably the unknown patterns of divergence their impact on heat budget near Equator, emerging Arctic up 82.5$^{\circ}$N. SKIM will also make unprecedented direct measurements strong from boundary currents Antarctic circumpolar current, interaction with waves expected impacts air-sea fluxes extreme For first time, directly measure vector...
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,...
A weakly nonhydrostatic, two‐layer numerical model based on the Boussinesq equations is presented which capable of describing, among others, generation and propagation nonlinear dispersive internal waves in Strait Gibraltar. The depends one space coordinate only, but it retains several features a fully three‐dimensional by including realistic bottom profile, variable channel width, trapezoidal cross section. primitive include horizontal diffusion, friction, friction between two water layers....
Abstract Repeated shipboard observation sections across the boundary flow off northeastern Brazil as well acoustic Doppler current profiler (ADCP) and current-meter records from a moored array deployed during 2000–04 near 11°S are analyzed here for both northward warm water by North Undercurrent (NBUC) above approximately 1100 m southward of Atlantic Deep Water (NADW) underneath. At 5°S, mean nine yields an NBUC transport 26.5 ± 3.7 Sv (Sv ≡ 106 m3 s−1) along boundary; at five is 25.4 7.4...
The open‐ocean oxygen minimum zone (OMZ) south and east of the Cape Verde Islands is studied from CTD hydrography, ADCP velocities, Argo float trajectories, historical data, with a focus on zonal supply drainage paths. strongest located north North Equatorial Countercurrent (NECC) at about 400 to 500‐m depth just above boundary between Central Water Antarctic Intermediate (AAIW). It shown that NECC, Undercurrent 4 6°N, northern branch NECC 8 10°N are sources for oxygen‐rich water supplied...
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...
Abstract Zonal wind anomalies in the western equatorial Atlantic during late boreal winter to early summer precondition cold/warm events eastern (EEA) that manifest a strong interannual cold tongue (ACT) variability. Local intraseasonal fluctuations, linked St. Helena anticyclone, contribute variability of onset and strength, particularly years with preconditioned shallow thermoclines. The impact sea surface temperature (SST) on field Gulf Guinea is assessed. It contributes northward...
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)...
The eastern boundary circulation off the coast of Angola has been described only sparsely to date, although it is a key element in understanding highly productive tropical marine ecosystem Angola. Here, we report for first time direct velocity observations Current (AC) at ∼11°S collected between July 2013 and October 2015 depth range from 45 450 m. measurements reveal an alongshore flow that dominated by intraseasonal seasonal variability with periodically alternating southward northward...