IOW Logo

PD Dr. Lars Umlauf

Image L. Umlauf

  Leibniz Institute for Baltic Sea Research Warnemünde (IOW)
  Seestrasse 15
  18119 Rostock
  Germany

  Email:      larsnull.umlauf@iow.de
  Phone: +49 (0)381 5197 223

 

Expertise

I am a physical oceanographer with a focus on turbulence, mixing, and small- to meso-scale processes in the ocean, in the Baltic Sea, and occasionally also in lakes.

Presently, my main working areas include the investigation of small-scale processes in the vicinity of surface-layer fronts, atmosphere-ocean feedbacks induced by diurnal warm layers and rain layers, the dynamics of rotating bottom gravity currents, internal-wave mixing, and boundary mixing processes in stratified basins.

I also collaborate with colleagues from other disciplines to understand how small-scale physical processes affect biogeoochemical interactions, e.g. in regions with large redox gradients.

In addition to theoretical, observational, and numerical methods used to understand these processes, I have a special interest in the development of marine turbulence models. Have a look at our public domain turbulence toolbox GOTM at www.gotm.net.

I am also involved in a number of scientific management and community services:

Curriculum Vitae

 

1991 - 1997

Department of Mechanics / Mechanical Engineering
TU Darmstadt (Germany) and UC Berkeley (USA)

1997 - 2001

PhD
TU Darmstadt (Germany)

2001 - 2003

Post-Doc
Ecole Polytechnique Fédéral de Lausanne (EPFL, Switzerland)

2003 - 2008

Post-Doc
Leibniz Institute for Baltic Sea Research Warnemünde

2013

Habilitation
Rostock University

2013

Jul-Dec: Guest Scientist at Oregon State University (USA)

2018

Apr-Jul: Guest Scientist at University of Victoria (Canada)

2026

Feb-Apr: Guest Scientist at Stanford University (USA)

Since 2008

Senior Researcher
Leibniz Institute for Baltic Sea Research Warnemünde

Since 2013

Lecturer ("Privatdozent")
Rostock University

Research

Frontal Dynamics and Water Mass Transformation

SkaMix field campaign
SkaMix field campaign in the Skagerrak

The ocean is in a perpetual motion that is enabled by Water Mass Transformation (WMT) processes, i.e., the mixing of different water masses and the exchange with the atmosphere that generates other water masses with different properties. Due to the vast size of the ocean basins, these WMT processes can hardly be observed and simulated in detail. Therefore, to address the WMT processes and their influence on the ocean dynamics, we study in this project the dynamics of a regional sea, the Skagerrak, that connects the North Sea and the Baltic Sea, using it as a natural laboratory for WMT processes. The circulation in the Skagerrak consists of three inflowing waters masses, the Jutland Current from the German Bight, the Baltic Outflow and the Atlantic Sea water. These water masses are then transformed into the outflowing waters of the Norwegian Coastal Current and the Baltic Inflow. The underlying WMT processes will be quantified by a suite of observational and numerical methods. We hypothesise that frontal dynamics in the surface waters are responsible for a large part of the WMT, but we will also aim to identify deep mixing processes. A ship campaign will be organised with two research vessels during spring / summer 2025, with synoptic observations concentrating on frontal dynamics. The ship time has been requested and is currently under review by the Review Panel German Research Vessels (GPF). During the cruise drifter experiments, microstructure observations and echo sounding surveys combined with remote sensing will be carried out. These observations will be augmented by existing long-term monitoring data from various sources. Swedish colleagues will support us by own cruises coordinated with us, deploying gliders and sail drones to provide detailed information on the vertical structure of the upper Skagerrak waters. A 15-year realistic numerical hindcast model simulation for the Skagerrak region will be set up to investigate the dynamics in the region. A nesting approach allows for resolving the eddy dynamics in the entire region, including foci on specific frontal regions that had been surveyed during the cruises. An existing Eulerian WMT framework will be further developed to quantify WMT processes in the region, including numerical truncation errors. A Lagrangian particle backtracking model will be integrated into the numerical model, to understand pathways of water masses, their residence times and mixing properties. In the end, we expect to have obtained a validated and complete assessment of the WMT processes in the Skagerrak that can be generalised and transferred to other regions. To internationally coordinate and carry out the WMT research in the Skagerrak, we have formed the SkaMix Consortium with a total of 20 members from Norway, Sweden, The Netherlands and Germany by signing a joint Memorandum of Understanding. For this project, we request one PhD student for the numerical modelling. One further PhD student for the field work will be paid by our institute.

Surface-Layer Dynamics

Surface-layer processes in the vicinity of a front
Surface-layer processes in the vicinity of a front

The surface mixing layer (SML) is the ocean side of the air-sea interface through which the fluxes of energy, momentum, and tracers have to pass in a coupled atmosphere-ocean system. Pathways and transformations of energy, momentum and tracers in the SML are complex, highly variable, and not suciently understood at the moment. Even in high-resolution ocean models, energy and momentum budgets for the surface layer are energetically inconsistent because the additional energy reservoirs and transformations due to unresolved processes (e.g., mesoscale/submesoscale motions, surface waves) are either ignored or not consistenty taken into account.

In our group, we currently focus on the dynamics and energetics of SML fronts and filaments. Different types of frontal instabilities may develop in the vicinity of such features, with important consequences for the transfer of energy among different processes and scales. We study these processes with the help of a high-resolution experimental approach, based on data from frontal regions in the Baltic Sea and the South Atlantic. The project is embeded in the large-scale research project on "Energy transfers in Atmosphere and Ocean" (TRR181), funded by the German Reseach Foundation (DFG). 

 

The role of intrusions

Intrusions
Sketch of small-scale interactions between intrusions and ambient waters with different biogeochemical composition. Arrows indicate solute exchange due to mixing of intrusions and adjacent water.

In an interdisciplinary project, conducted in collaboration with colleages from IOW's departments of marine biology and marine chemistry, we are currently investigating the role of intermittent intrusions and mixing on the microbiology and biogeochemistry of pelagic redoxclines (oxic-anoxic interfaces) based on a purely experimental approach. One key component of the project is a moored autonomous profiling system in the central Baltic Sea, developed in collaboration with IOW’s chemistry department, in order to study the evolution of the Baltic Sea redoxcline over longer time scales. For the purpose of this project, this platform was extended by an autonomous turbulence microstructure package and a high-resolution current profiler (ADCP) for the observation of mixing rates and mixing processes in the vicinity of intrusions.

The evaluation of long-term records by Holtermann et al. (2019) showed that intrusions are ubiquitous features in the central Baltic Sea. Intrusions determine the depth of the redoxcline, and import, over decadal time scales, considerably more oxygen into the deep layers of the Baltic Sea than the more well-known Major Baltic Inflows (MBIs). The turbulence sensors mounted on the autonomous profiling platform provided a number of especially suprising results. Different from previous assumptions, they did not show any indications of enhanced shear-induced turbulence in the vicinity of intrusions or even during an MBI that occured during the measurements (Holtermann et al., 2017), supporting the view that most of the deep-water mixing occurs in the turbulent bottom boundary layers. Secondly, our moored turbulence observations also provided the first direct evidence for the important of diffusive convection (Holtermann et al., 2017; Umlauf et al., 2018). It has long been speculated that this particular mixing process, relevant especially in the Arctic Ocean, might also be relevant in the Baltic Sea. Our study has also shown that the mixing of intruding and ambient waters has an important effect on the abundance, activity, and gene expressions of microorganisms in the vicinity of redox interfaces (Schmale et al., 2016; Beier et al., 2019).

 

Turbulent Bottom Boundary Layers

Schematic view of the turbulent bottom boundary layer
Schematic view of the turbulent bottom boundary layer during different phases of an oscillating cross-slope flow. The gray-shaded areas near the bottom denote regions with suspended sediment. Modified figure from Schulz and Umlauf (2016).

Turbulent bottom boundary layers (BBLs) are important hotspots of energy dissipation, mixing, and transport processes in most marine and limnic systems. They often provide an essential contribution to basin-scale energy dissipation and mixing, determine the exchange of dissolved substances between the sediment and the water column, and control the transport of suspended material.

Our group has focused in the past in particular on stratification effects in oscillating boundary layers near topographic slopes, including those generated by barotropic and baroclinic tides, near-inertial waves, and so-scalled internal "seiches" (long standing internal waves) in lakes. Together with physical limnologists from the EAWAG (Switzerland), we investigated the basin-scale effects of periodically unstable boundary layers in small lakes with the help of a high-resolution numerical modeling study (Becherer and Umlauf, 2011; Lorrai et al., 2011). Using a simple one-dimensional theoretical framework, we showed how important BBL properties like the mixing effeciency and the residual transport changes as a function of forcing conditions, slope, stratification, rotation rate, and other relevant parameters (Umlauf and Burchard, 2011; Umlauf et al., 2015). As one result of this work, it turned out that oscillating boundary layers near sloping topography have many similarities with tidal straining processes in regions of fresh-water influence in estuaries and the coastal ocean. Schulz and Umlauf (2016) and Schulz et al. (2017) showed that asymmetries in turbulence in oscillating BBLs result in residual sediment transports, which are likely to occur everywhere in the ocean where a stratified oscillating flow occurs in the vicinity of sloping topography.

Dynamics of rotating gravity currents

Density and turbulence structure in a channelized gravity current
Turbulence dissipation rate and density structure (black contour lines) in a rotating gravity current in the western Baltic Sea (modified figure from Umlauf et al., 2007)

Gravity currents in rotating reference frames are a fascinating and, due to their importance for the ocean general circulation, intensively studied topic. Gravity currents in the virtually tideless Baltic Sea occur at much shallower depths and exhibit smaller spatial scales than their large-scale counterparts in the deep ocean. Nevertheless, they share many features with these large-scale overflows, e.g. the high Reynolds numbers, strong rotational effects, and subcritical Froude numbers. The smaller spatial scales make the gravity currents in the Baltic more easily accessible for high-resolution measurements of hydrographic and turbulence parameters. We exploit this advantage, and use the Baltic Sea as a natural laboratory for deriving generally applicable models of rotating bottom gravity currents (Umlauf and Arneborg 2009a,b; Arneborg et al., 2007; Umlauf et al., 2007).

As an example for the available data sets, the figure to the right shows a complete microstructure and CTD transect across a gravity current passing through an approximately 10 km wide channel in the Western Baltic. The high sampling density (more than 70 profiles for this figure) allowed us to compute detailed transects of turbulence parameters across the whole width of the gravity current, from which the essential non-dimensional numbers describing rotating gravity currents can be derived: the Froude number, the Ekman number, the entraiment rate, the drag coefficient, etc. We collaborate with colleagues from IOW's regional ocean modeling group to gain a better understanding of the physical processes in such flows (Umlauf et al., 2010), and with researchers from other disciplines to investigate the biogeochemical implications of mixing in gravity currents (Schmale et al., 2016).

 

Internal-Wave Mixing

Boundary Mixing (Baltic Sea)
Logarithm of (a) buoyancy frequency and (b) turbulence dissipation rate and density structure (black contour lines) from a transect across sloping topography in the Southern Baltic Sea. Adapted from Lappe and Umlauf (2016).

Internal waves are ubiquitous features in the ocean. They play an important role in the energy budget of the ocean due to their ability to distribute energy over large distances, both vertically and horizontally, and among a large range of scales by non-linear interactions and their ability to generate small-scale turbulence by breaking. The latter is believed to be an important energy source for diapycnal mixing of heat, salt, and dissolved substances.

In our group, we use the Baltic Sea as a natural laboratory to study these processes with focus on wind-generated near-inertial waves. These waves with a period of approximately 14 h often form the strongest signal in measured and modeled currents. We showed that the vertical shear associated with the near-inertial waves triggers shear instabilities, and thus mixing, in the strongly stratified interior region of the deep basins of the Baltic Sea (van der Lee and Umlauf, 2011). More recently, measurements near one of the slopes of the Bornholm Basin (see figure to the right) showed that near-inertial waves are also one of the most important energy sources for boundary mixing (Lappe and Umlauf, 2016). This is in line with results from the Baltic Sea Tracer Releaser Experiment (Holtermann et al., 2012; Holtermann and Umlauf, 2012; Holtermann et al., 2014), suggesting that boundary mixing processes dominate net vertical mixing in the deep layers of the Baltic Sea.

 

Turbulence Modeling

GOTM - The General Ocean Turbulence Model
GOTM - The General Ocean Turbulence Model

The focus of this area of research is the development and testing of turbulence models for stratified turbulent flows. The class of models we are mainly interested in are so-called one-point turbulence closure models, in particular second-moment closures.

Among the models developed by our group is a version of the k-ω model for stratified flows (Umlauf et al., 2003), and a generic length scale model (GLM) from which almost all traditional models (e.g. the k-ε model and the Mellor-Yamada model) can be recovered as special cases (Umlauf and Burchard, 2003). More information about these and related models can be found in the review article by Umlauf and Burchard (2005).

The turbulence models developed by us and other groups are implemented in our public domain turbulence library GOTM (Umlauf et al, 2005). Either via an interface to GOTM or as stand-alone versions, these turbulence models have been implemented in a number of three-dimensional ocean models (ROMS, OPA, MOM4, POLCOMS, GETM, etc.). 

For more information about GOTM and our three-dimensional circulation model GETM, check out our web sites at www.gotm.net and www.getm.eu.

 

 

Baltic Sea Tracer Experiment

Image of Gotland Basin and tracer distribution
Eastern Gotland Basin (left) with tracer and CTD profiles

One of the outstanding questions for the Baltic Sea ecosystem is how physical and bio-geochemical properties of the deep layers communicate with the surface mixed layer where production takes place. In a joint project of IOW and GEOMAR (Kiel), we investigated these mixing processes in the framework of the Baltic Sea Tracer Release Experiment (BaTRE), conducted in the years 2007-2010.

In collaboration with the tracer research group of Jim Ledwell (WHOI), a new type of tracer, CF3SF5, was injected in September 2007 into the deep waters of the Eastern Gotland Basin with the help of the new Oceanic Tracer Injection System (OTIS) built for this project (see Umlauf et al. 2008). The figure to the right shows the study area, the vertical distribution of the tracer (markers in highlighted area), and some hydrographic parameters as measured approximately two weeks after the injection.

The experiment was accompanied by extensive turbulence measurments in order to obtain direct mixing estimates for comparision with the basin-scale mixing inferred from the vertical spreading of the tracer cloud. Combined with additional moored instrumentation (ADCPs, current meters, CTD loggers), a coherent data set could be obtained. A key result of this project was the observation that deep-water mixing in the central Baltic Sea occurs almost exclusively in the turbulent boundary layers on the topographic slopes of the basin (Holtermann et al., 2012; Holtermann and Umlauf, 2012). This finding challenged the traditional view about how mixing works in the Baltic Sea, and how it should be parameterized in numerical models (Holtermann et al., 2014).

Projects

Teaching

Hydrodynamics (Physics BSc and MSc)

This course contains an introduction to modern fluid mechanics, based on the first principles of classical mechanics and thermodynamics (conservation of mass, momentum, energy, etc.). There are no special prerequisites except some basic knowledge in calculus, linear algebra, and simple differential equations. "Hydrodynamics" is part of the Physics BSc and MSc programs but is equally suited and understandable for students from mathematics and engineering. This lecture should be particularly intersting for students planning to specialize in the Physics of the Ocean, Atmosphere, and Space in the Physics MSc program, for which this course is obligatory. The focus of the lecture is a carefully and mathematically sound derivation of the equations describing the motion of Newtonian fluids (Navier-Stokes Equations), and the discussion of simplifications leading to the famous Euler and Bernoulli equations. Special solutions of these equations will be discussed. The lecture is accompanied by bi-weekly excercise sessions with hands-on training and practical examples.

Turbulence in Fluids (Physics MSc)

This class provides a basic introduction into the fascinating world of turbulence in fluids, including a discussion of the basic equations of fluid motion, flow instability and chaos, statistical methods, spectral theory of turbulence, and state-of-the-art techniques to observe fluid turbulence. The lectures will be accompanied by a series of bi-weekly exercise sessions, allowing students to work with real data sets, and deepen their understanding of the material treated during the lectures. We will also conduct and analyze a laboratory experiment. This class is part of the Physics MSc program but is equally recommended for students from neighboring discplines like mathematics and engineering. Basic knowledge in fluid mechanics (Navier-Stokes equations) is advantageous but not strictly required. It is especially recommended for Physics students following the study track Physics of Ocean, Atmosphere, and Space.

Fourier Series and Spectral Analysis

Here, you find some supplementary material describing the basic spectral techniques required in turbulence theory and other applications in geophysics.These notes contain a brief introduction on Fourier series and transforms, spectra and co-spectra, filtering, and discrete Fourier transforms (DFT). Some MATLAB routines are provided were these things can be conveniently explored (using the same notation as in the notes).

Download material:

Notes on spectral analysis

MATLAB tools for spectral analysis and filtering

Publications

2026

  • Beal, L. M., L. Chafik, K. Chakraborty, S. Fawcett, X. Wang, B. Fernández Castro, M. Flexas, N. F. Goodkin, Z. Lachkar, Y. Li, A. Meyer, R. P. Mulligan, T. Nagai, P. N. Vinayachandran, H. E. Power, G. Saldías, C. Sherwood, A. Singh, L. Umlauf, M. Vancoppenolle, A. Wahlin and F. Xu (2026). A Special Thank You to Our 2025 Reviewers [Editorial]. J. Geophys. Res. Oceans 131: e2026JC024338, doi: 10.1029/2026JC024338
  • Kuss, J., P. Holtermann, L. Umlauf, O. Dellwig, R. D. Prien and J. J. Waniek (2026). The Changing Baltic Sea: Between Nutrient Load Reduction and a Warming Climate. Annu. Rev. Mar. Sci. 18: 219–244, doi: 10.1146/annurev-marine-040324-020707

2025

  • Henell, E., H. Burchard, U. Gräwe, P. Holtermann, M. Naumann, L. Umlauf and K. Klingbeil (2025). Exploring the variability of a non-tidal marginal sea with a single-model ensemble. Ocean Model. 198: 102615, doi: 10.1016/j.ocemod.2025.102615
  • Miracca-Lage, M., C. Ménesguen, M. Schmitt, L. Umlauf, L. Merckelbach and J. R. Carpenter (2025). Turbulence Observations and Energetics of Diurnal Warm Layers. J. Phys. Oceanogr. 55: 2141–2158, doi: 10.1175/JPO-D-25-0026.1
  • Peng, J.-P., N. L. Jones, M. D. Rayson, M. Schmitt, L. Umlauf, C. Whitwell, S. R. Keating, C. J. Shakespeare and G. N. Ivey (2025). Interactions Between Diurnal Warm Layers and Surface-Layer Fronts. J. Geophys. Res. Oceans 130: e2024JC021380, doi: 10.1029/2024JC021380
  • Schmale, O., V. Mohrholz, S. Papenmeier, K. Jürgens, M. Blumenberg, P. Feldens, S. Jordan, P. Ruiz-Fernández, C. Meeske, J. Fabian, S. Iwe and L. Umlauf (2025). The control of physical and biological drivers on pelagic methane fluxes in a Patagonian fjord (Golfo Almirante Montt, Chile). Sci. Total Environ. 982: 179584, doi: 10.1016/j.scitotenv.2025.179584
  • Schmitt, M., K. Klingbeil, R. Shevchenko and L. Umlauf (2025). Three-Dimensional Ocean Surface Layer Response to Atmospheric Cold Pools and Diurnal Heating in the Trade Wind Regime. J. Geophys. Res. Oceans 130: e2024JC022129, doi: 10.1029/2024JC022129

2024

  • Burchard, H., M. Alford, M. Chouksey, G. Dematteis, C. Eden, I. Giddy, K. Klingbeil, A. Le Boyer, D. Olbers, J. Pietrzak, F. Pollmann, K. Polzin, F. Roquet, P. S. Saez, S. Swart, L. Umlauf, G. Voet and B. Wynne-Cattanach (2024). Linking ocean mixing and overturning circulation. Bull. Amer. Meteorol. Soc. 105: E1265-E1274, doi: 10.1175/BAMS-D-24-0082.1
  • Naumann, M., U. Gräwe, L. Umlauf, H. Burchard, V. Mohrholz, J. Kuss, M. Kanwischer, H. Osterholz, S. Feistel, I. Hand, J. J. Waniek and D. E. Schulz-Bull (2024). Hydrographic-hydrochemical assessment of the Baltic Sea 2022. Warnemünde: Leibniz Institute for Baltic Sea Research. (Meereswissenschaftliche Berichte), doi: 10.12754/msr-2024-0127
  • Schmitt, M., H. T. Pham, S. Sarkar, K. Klingbeil and L. Umlauf (2024). Diurnal Warm Layers in the ocean: Energetics, non-dimensional scaling, and parameterization. J. Phys. Oceanogr. 54: 1037–1055, doi: 10.1175/JPO-D-23-0129.1

2023

  • Muchowski, J., L. Arneborg, L. Umlauf, P. Holtermann, E. Eisbrenner, C. Humborg, M. Jakobsson and C. Stranne (2023). Diapycnal mixing induced by rough small-scale bathymetry. Geophys. Res. Lett. 50: e2023GL103514, doi: 10.1029/2023GL103514
  • Muchowski, J., M. Jakobsson, L. Umlauf, L. Arneborg, B. Gustafsson, P. Holtermann, C. Humborg and C. Stranne (2023). Observations of strong turbulence and mixing impacting water exchange between two basins in the Baltic Sea. Ocean Sci. 19: 1809-1825, doi: 10.5194/os-19-1809-2023
  • Umlauf, L., K. Klingbeil, H. Radtke, R. Schwefel, J. Bruggeman and P. Holtermann (2023). Hydrodynamic control of sediment-water fluxes: Consistent parameterization and impact in coupled benthic-pelagic models. J. Geophys. Res. Oceans 128: e2023JC019651, doi: 10.1029/2023JC019651

2022

  • Beal, L. M., L. Padman, L. Zhou, A. Singh, D. Chambers, M. Friedrichs, C. Gnanaseelan, N. Goodkin, R. Hetland, R. Mulligan, T. Nagai, J. O'Callaghan, N. Pinardi, H. Power, L. Umlauf, A. Wahlin and F. Xu (2022). What's new at JGR-Oceans? Confronting bias, burn out, and big data. J. Geophys. Res. Oceans 127: e2022JC019539, doi: 10.1029/2022JC019539
  • Burchard, H., K. Bolding, A. Jenkins, M. Losch, M. Reinert and L. Umlauf (2022). The vertical structure and entrainment of subglacial melt water plumes. J. Adv. Model. Earth Syst. 14: e2021MS002925, doi: 10.1029/2021MS002925
  • Chrysagi, E., N. B. Basdurak, L. Umlauf, U. Gräwe and H. Burchard (2022). Thermocline salinity minima due to wind-driven differential advection. J. Geophys. Res. Oceans 127: e2022JC018904, doi: 10.1029/2022JC018904
  • Holtermann, P., O. Pinner, R. Schwefel and L. Umlauf (2022). The role of boundary mixing for diapycnal oxygen fluxes in a stratified marine system. Geophys. Res. Lett. 49: e2022GL098917, doi: 10.1029/2022GL098917
  • Klingbeil, K., E. Deleersnijder, O. Fringer and L. Umlauf (2022). Basic equations of marine flows. In: The Mathematics of Marine Modelling: Water, Solute and Particle Dynamics in Estuaries and Shallow Seas. Ed. by H. Schuttelaars, A. Heemink and E. Deleersnijder. Cham: Springer International Publishing: 1-9, 978-3-031-09559-7, doi: 10.1007/978-3-031-09559-7_1
  • Muchowski, J., L. Umlauf, L. Arneborg, P. Holtermann, E. Weidner, C. Humborg and C. Stranne (2022). Potential and limitations of a commercial broadband echo sounder for remote observations of turbulent mixing. J. Atmos. Ocean. Technol. 39: 1985-2003, doi: 10.1175/jtech-d-21-0169.1

2021

  • Chrysagi, E., L. Umlauf, P. Holtermann, K. Klingbeil and H. Burchard (2021). High-resolution simulations of submesoscale processes in the Baltic Sea: The role of storm events. J. Geophys. Res. Oceans 126: e2020JC016411, doi: 10.1029/2020JC016411
  • Li, Q., J. Bruggeman, H. Burchard, K. Klingbeil, L. Umlauf and K. Bolding (2021). Integrating cvmix into gotm (v6.0): A consistent framework for testing, comparing, and applying ocean mixing schemes. Geosci. Model Dev. 14: 4261-4282, doi: 10.5194/gmd-14-4261-2021
  • Peng, J.-P., J. Dräger-Dietel, R. P. North and L. Umlauf (2021). Diurnal variability of frontal dynamics, instability, and turbulence in a submesoscale upwelling filament. J. Phys. Oceanogr. 51: 2825-2843, doi: 10.1175/jpo-d-21-0033.1

2020

  • Carpenter, J. R., A. Rodrigues, L. K. P. Schultze, L. M. Merckelbach, N. Suzuki, B. Baschek and L. Umlauf (2020). Shear instability and turbulence within a submesoscale front following a storm. Geophys. Res. Lett. 47: e2020GL090365, doi: 10.1029/2020GL090365
  • Holtermann, P., R. Prien, M. Naumann and L. Umlauf (2020). Interleaving of oxygenized intrusions into the Baltic Sea redoxcline. Limnol. Oceanogr. 65: 482-503, doi: 10.1002/lno.11317
  • Peng, J.-P., P. Holtermann and L. Umlauf (2020). Frontal instability and energy dissipation in a submesoscale upwelling filament. J. Phys. Oceanogr. 50: 2017-2035, doi: 10.1175/jpo-d-19-0270.1

2019

  • Beier, S., P. Holtermann, D. Numberger, T. Schott, L. Umlauf and K. Jürgens (2019). A metatranscriptomics-based assessment of small-scale mixing of sulfidic and oxic waters on redoxcline prokaryotic communities. Environ. Microbiol. 21: 584-602, doi: doi:10.1111/1462-2920.14499

2018

  • Bartl, I., I. Liskow, K. Schulz, L. Umlauf and M. Voss (2018). River plume and bottom boundary layer - Hotspots for nitrification in a coastal bay? Estuar. Coast. Shelf Sci. 208: 70-82, doi: 10.1016/j.ecss.2018.04.023
  • Burchard, H., K. Bolding, R. Feistel, U. Gräwe, K. Klingbeil, P. MacCready, V. Mohrholz, L. Umlauf and E. M. v. d. Lee (2018). The Knudsen theorem and the Total Exchange Flow analysis framework applied to the Baltic Sea. Prog. Oceanogr. 165: 268-286, doi: 10.1016/j.pocean.2018.04.004
  • Naumann, M., L. Umlauf, V. Mohrholz, J. Kuss, H. Siegel, J. J. Waniek and D. E. Schulz-Bull (2018). Hydrographic-hydrochemical assessment of the Baltic Sea 2017. Rostock: Leibniz Institute for Baltic Sea Research Warnemünde. 97 S. (Meereswissenschaftliche Berichte = Marine Science Reports ; 107), doi: 10.12754/msr-2018-0107
  • Umlauf, L., P. L. Holtermann, C. A. Gillner, R. D. Prien, L. Merckelbach and J. R. Carpenter (2018). Diffusive convection under rapidly varying conditions. J. Phys. Oceanogr. 48: 1731-1747, doi: 10.1175/jpo-d-18-0018.1

2017

  • Holtermann, P. L., R. Prien, M. Naumann, V. Mohrholz and L. Umlauf (2017). Deepwater dynamics and mixing processes during a major inflow event in the central Baltic Sea. J. Geophys. Res. Oceans: online, doi: 10.1002/2017JC013050
  • Naumann, M., L. Umlauf, V. Mohrholz, J. Kuss, H. Siegel, J. Waniek and D. Schulz-Bull (2017). Hydrographic-hydrochemical assessment of the Baltic Sea 2016. Rostock: Leibniz Institute for Baltic Sea Research Warnemünde. 94 S. (Meereswissenschaftliche Berichte = Marine Science Reports ; 104), doi: 10.12754/msr-2016-0101
  • Schulz, K., T. Endoh and L. Umlauf (2017). Slope-induced tidal straining: Analysis of rotational effects. J. Geophys. Res. Oceans 122: 2069-2089, doi: 10.1002/2016JC012448
  • Umlauf, L., and C. Lappe: Randmischungsprozesse bestimmen den vertikalen Transport im Tiefenwasser der Ostsee. Article in the Annual Report 2016, Leibniz-Institut for Baltic Sea Research Warnemünde

2016

  • Becherer, J., G. Flöser, L. Umlauf and H. Burchard (2016). Estuarine circulation versus tidal pumping: sediment transport in a well-mixed tidal inlet. J. Geophys. Res. Oceans 121: 6251-6270, doi: 10.1002/2016JC011640
  • Endoh, T., Y. Yoshikawa, T. Matsuno, Y. Wakata, K.-J. Lee and L. Umlauf (2016). Observational evidence for tidal straining over a sloping continental shelf. Cont. Shelf Res. 117: 12-19, doi: 10.1016/j.csr.2016.01.018
  • Lappe, C. and L. Umlauf (2016). Efficient boundary mixing due to near-inertial waves in a nontidal basin: observations from the Baltic Sea. J. Geophys. Res. Oceans 121: 8287-8304, doi: 10.1002/2016JC011985
  • Moghimi, S., J. Thomson, T. Özkan-Haller, L. Umlauf and S. Zippel (2016). On the modeling of wave-enhanced turbulence nearshore. Ocean Model. 103: 118-132, doi: 10.1016/j.ocemod.2015.11.004
  • Schmale, O., S. Krause, P. Holtermann, N. C. Power Guerra and L. Umlauf (2016). Dense bottom gravity currents and their impact on pelagic methanotrophy at oxic/anoxic transition zones. Geophys. Res. Lett. 43: 5225-5232, doi: 10.1002/2016GL069032
  • Schulz, K. and L. Umlauf (2016). Residual transport of suspended material by tidal straining near sloping topography. J. Phys. Oceanogr. 46: 2083-2102, doi: 10.1175/JPO-D-15-0218.1

2015

  • Becherer, J., M. T. Stacey, L. Umlauf and H. Burchard (2015). Lateral circulation generates flood tide stratification and estuarine exchange flow in a curved tidal inlet. J. Phys. Oceanogr. 45: 638-656, doi: 10.1175/JPO-D-14-0001.1
  • Nausch, G., M. Naumann, L. Umlauf, V. Mohrholz and H. Siegel (2015). Hydrographic-hydrochemical assessment of the Baltic Sea 2014. Rostock: Leibniz Institute for Baltic Sea Research Warnemünde. 91 S. (Meereswissenschaftliche Berichte = Marine Science Reports ; 96), doi: 10.12754/msr-2015-0096
  • Umlauf, L., W. D. Smyth and J. N. Moum (2015). Energetics of bottom Ekman layers during buoyancy arrest. J. Phys. Oceanogr. 45: 3099-3117, doi: 10.1175/JPO-D-15-0041.1

2014

  • Burchard, H., U. Gräwe, P. Holtermann, K. Klingbeil and L. Umlauf (2014). Turbulence closure modelling in coastal waters. Küste, 81: 69-87
  • Holtermann, P. L., H. Burchard, U. Gräwe, K. Klingbeil and L. Umlauf (2014). Deep-water dynamics and boundary mixing in a nontidal stratified basin: a modeling study of the Baltic Sea. J. geophys. res. oceans 119: 1465-1487, doi:10.1002/2013JC009483
  • Nausch, G., M. Naumann, L. Umlauf, V. Mohrholz and H. Siegel (2014). Hydrographisch-hydrochemische Zustandseinschätzung der Ostsee 2013. [Electronic Book] Warnemünde: Leibniz-Institut für Ostseeforschung Warnemünde. 104 S. (Meereswissenschaftliche Berichte = Marine Science Reports ; 93), doi:10.12754/msr-2014-0093
  • Yamazaki, H., C. Locke, L. Umlauf, H. Burchard, T. Ishimaru and D. Kamykowski (2014). A Lagrangian model for phototaxis-induced thin layer formation. Deep-sea res. Pt. 2. 101: 193-206, doi:10.1016/j.dsr2.2012.12.010

2013

2012

  • Dellwig, O., B. Schnetger, H.-J. Brumsack, H.-P. Grossart and L. Umlauf (2012). Dissolved reactive manganese at pelagic redoxclines (part II): hydrodynamic conditions for accumulation. J. mar. syst. 90: 31-41, doi:10.1016/j.jmarsys.2011.08.007
  • Holtermann, P. L. and L. Umlauf (2012). The Baltic Sea tracer release experiment: 2. mixing processes. J. geophys. res. 117: C01022, doi:10.1029/2011jc007445
  • Holtermann, P. L., L. Umlauf, T. Tanhua, O. Schmale, G. Rehder and J. J. Waniek (2012). The Baltic Sea tracer release experiment: 1. mixing rates. J. geophys. res. 117: C01021, doi:10.1029/2011JC007439
  • Nausch, G., R. Feistel, L. Umlauf, V. Mohrholz, K. Nagel and H. Siegel (2012). Hydrographisch-hydrochemische Zustandseinschätzung der Ostsee 2011. Warnemünde: Leibniz-Institut für Ostseeforschung Warnemünde. 121 S. (Meereswissenschaftliche Berichte; 86) http://www.io-warnemuende.de/tl_files/forschung/meereswissenschaftliche-berichte/mebe86_2012-zustand-hc.pdf
  • Smyth, W. D., H. Burchard and L. Umlauf (2012). Baroclinic interleaving instability: a second-moment closure approach. J. phys. oceanogr. 42: 764-784, doi:10.1175/JPO-D-11-066.1

2011

  • Becherer, J. K. and L. Umlauf (2011). Boundary mixing in lakes: 1. Modeling the effect of shear-induced convection. J. geophys. res. 116: C10017, doi:10.1029/2011jc007119
  • Becherer, J., H. Burchard, G. Flöser, V. Mohrholz and L. Umlauf (2011). Evidence of tidal straining in well-mixed channel flow from micro-structure observations. Geophys. res. lett. 38, 1: L17611, doi:10.1029/2011gl049005
  • König, J., W. Fennel, T. Seifert, G. Nausch, S. Sagert, L. Umlauf, V. Mohrholz, T. Neumann and F. G. Jakobsen (2011). Fehmarnbelt Fixed Link Hydrographic Services (FEHY): marine water baseline, hydrography, water quality and plankton of the Baltic Sea - baseline. Vol. I. Prepared for: Femern A/S. [Report] E1TR0057, proprietary report. Hørsholm: DHI / IOW Consortium in association with LICengineering, Bolding & Burchard and Risø DTU. 210 S.
  • Lorrai, C., L. Umlauf, J. K. Becherer, A. Lorke and A. Wüest (2011). Boundary mixing in lakes: 2. Combined effects of shear- and convectively induced turbulence on basin-scale mixing. J. geophys. res. 116: C10018, doi:10.1029/2011jc007121
  • Nausch, G., R. Feistel, L. Umlauf, V. Mohrholz and H. Siegel (2011). Hydrographisch-chemische Bedingungen in der deutschen ausschließlichen Wirtschaftszone der Ostsee (AWZ) im Jahr 2010. [Report] Warnemünde: Leibniz-Institut für Ostseeforschung Warnemünde, im Auftrag des Bundesamtes für Seeschifffahrt und Hydrographie Hamburg und Rostock. 68 S.
  • Umlauf, L. and H. Burchard (2011). Diapycnal transport and mixing efficiency in stratified boundary layers near sloping topography. J. phys. oceanogr. 41: 329-345, doi:10.1175/2010JPO4438.1
  • van der Lee, E. M. and L. Umlauf (2011). Internal wave mixing in the Baltic Sea: near-inertial waves in the absence of tides. J. geophys. res. 116: C10016, doi:10.1029/2011jc007072

2010

  • Nausch, G., R. Feistel, L. Umlauf, K. Nagel and H. Siegel (2010). Hydrographisch-chemische Bedingungen in der deutschen ausschließlichen Wirtschaftszone (AWZ) im Jahr 2009. Warnemünde: Leibniz-Institut für Ostseeforschung Warnemünde, im Auftrag des Bundesamtes für Seeschifffahrt und Hydrographie Hamburg und Rostock. 73 S.
  • Nausch, G., R. Feistel, L. Umlauf, K. Nagel and H. Siegel (2010). Hydrographisch-chemische Zustandseinschätzung der Ostsee 2009. Meereswiss. Ber. 80: 3-107
  • Umlauf, L., L. Arneborg, R. Hofmeister and H. Burchard (2010). Entrainment in shallow rotating gravity currents: a modeling study. J. phys. oceanogr. 40: 1819-1834, doi:doi:10.1175/2010JPO4367.1

2009

  • Burchard, H., F. Janssen, K. Bolding, L. Umlauf and H. Rennau (2009). Model simulations of dense bottom currents in the Western Baltic Sea. Cont. shelf res. 29: 205-220, doi:10.1016/j.csr.2007.09.010
  • Nausch, G., R. Feistel, L. Umlauf, K. Nagel and H. Siegel (2009). Hydrographisch-chemische Bedingungen in der deutschen ausschließlichen Wirtschaftszone (AWZ) im Jahr 2008. Warnemünde: Leibniz-Institut für Ostseeforschung Warnemünde, im Auftrag des Bundesamtes für Seeschifffahrt und Hydrographie Hamburg und Rostock. 61 S.
  • Nausch, G., R. Feistel, L. Umlauf, K. Nagel and H. Siegel (2009). Hydrographisch-chemische Zustandseinschätzung der Ostsee 2008. Meereswiss. Ber. 77: 3-99
  • Reissmann, J. H., H. Burchard, R. Feistel, E. Hagen, H. U. Lass, V. Mohrholz, G. Nausch, L. Umlauf and G. Wieczorek (2009). Vertical mixing in the Baltic Sea and consequences for eutrophication – a review. Prog. oceanogr. 82: 47-80, doi:10.1016/j.pocean.2007.10.004
  • Umlauf, L. (2009). The description of mixing in stratified layers without shear in large-scale ocean models. J. phys. oceanogr. 39: 3032-3039, doi:10.1175/2009jpo4006.1
  • Umlauf, L. and L. Arneborg (2009). Dynamics of rotating shallow gravity currents passing through a channel : Part I: Observation of transverse structure. J. phys. oceanogr. 39: 2385-2401, doi:10.1175/2009JPO4159.1
  • Umlauf, L. and L. Arneborg (2009). Dynamics of rotating shallow gravity currents passing through a channel : Part II: Analysis. J. phys. oceanogr. 39: 2402-2416, doi:10.1175/2009JPO4164.1

2008

  • Burchard, H., L. Umlauf and F. Peters (2008). Impact of small-scale physics on marine biology. J. mar. syst. 70: 215-308 [Editorial]
  • Burchard, H., L. Umlauf and F. Peters, Eds. (2008). Impact of small-scale physics on marine biology : selected papers from the 2nd Warnemünde Turbulence Days, 28-30 September 2005, Rostock, Germany. Amsterdam: Elsevier. 215-308 S. (Journal of marine systems, special issue, vol. 70, no. 3/4)
  • Holt, J. and L. Umlauf (2008). Modelling the tidal mixing fronts and seasonal stratification of the Northwest European continental shelf. Cont. shelf res. 28: 887-903
  • Lorke, A., L. Umlauf and V. Mohrholz (2008). Stratification and mixing on sloping boundaries. Geophys. res. lett. 35: L14610, doi:10.1029/2008GL034607
  • Nausch, G., R. Feistel, L. Umlauf, K. Nagel and H. Siegel (2008). Hydrographisch-chemische Zustandseinschätzung der Ostsee 2007. Meereswiss. Ber. 72: 3-93
  • Umlauf, L., T. Tanhua, J. J. Waniek, O. Schmale, P. Holtermann and G. Rehder (2008). Hunting a new oceanic tracer. 89, 43: 419-420
  • Wieczorek, G., E. Hagen and L. Umlauf (2008). Eastern Gotland Basin case study of thermal variability in the wake of deep water intrusions. J. mar. syst. 74: S65-S79

2007

  • Arneborg, L., V. Fiekas, L. Umlauf and H. Burchard (2007). Gravity current dynamics and entrainment - A process study based on observations in the Arkona Basin. J. phys. oceanogr. 37: 2094-2113
  • Umlauf, L. and G. Kirillin, Eds. (2007). Proceedings of the 11th workshop on Physical Processes in Natural Waters, Warnemünde, Germany, 3-6 September, 2007. Berlin: Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB). 197 S. (Berichte des IGB ; 25)
  • Umlauf, L., L. Arneborg, H. Burchard, V. Fiekas, H. U. Lass, V. Mohrholz and H. Prandke (2007). Transverse structure of turbulence in a rotating gravity current. Geophys. res. lett. 34: L 08601, doi:10.1029/2007GL029521, (1-5)
  • Yakushev, E. V., F. Pollehne, G. Jost, I. Kuznetsov, B. Schneider and L. Umlauf (2007). Analysis of the water column oxic/anoxic interface in the Black and Baltic Seas with a numerical model. Mar. chem. 107: 388-410

2006

  • Burchard, H., K. Bolding, W. Kühn, A. Meister, T. Neumann and L. Umlauf (2006). Description of a flexible and extendable physical-biogeochemical model system for the water column. J. mar. syst. 61: 180-211
  • Sellschopp, J., L. Arneborg, M. Knoll, V. Fiekas, F. Gerdes, H. Burchard, H. U. Lass, V. Mohrholz and L. Umlauf (2006). Direct observations of a medium-intensity inflow into the Baltic Sea. Cont. shelf res. 26: 2393-2414
  • Yakushev, E. V., F. Pollehne, G. Jost, I. Kuznetsov, B. Schneider and L. Umlauf (2006). Redox Layer Model (ROLM): a tool for analysis of the water column oxic/anoxic interface processes. Warnemünde: Institut für Ostseeforschung. 54 S. (Meereswissenschaftliche Berichte; 68)

2005

  • Burchard, H. and L. Umlauf (2005). Observations and numerical modelling of mixed layer turbulence: do the represent the same statistical quantities? Deep-sea res. Pt. 2. 52: 1069-1074 [Editorial]
  • Burchard, H. and L. Umlauf, Eds. (2005). Observations and modelling of mixed layer turbulence: do the represent the same statistical quantities? (Special issue from the First Warnemünde Turbulence Days, sept. 17-19, 2003). 1069-1357 S. (Deep-Sea research Part 2. vol. 52, no.9-10)
  • Burchard, H., H. U. Lass, V. Mohrholz, L. Umlauf, J. Sellschopp, V. Fiekas, K. Bolding and L. Arneborg (2005). Dynamics of medium-intensity dense water plumes in the Arkona Sea, Western Baltic Sea. Ocean dyn. 55: 391-402
  • Umlauf, L. (2005). Modelling the effects of horizontal and vertical shear in stratified turbulent flows. Deep-sea res. Pt. 2. 52: 1181-1201
  • Umlauf, L. and H. Burchard (2005). A generic transport equation for the lenght scale in turbulent flows. In: Marine turbulence : theories, observations and models. Ed. by H. Z. Baumert, J. H. Simpson and J. Sündermann. Cambrigde: Cambrigde Univ. Press: 188-196
  • Umlauf, L. and H. Burchard (2005). Second-order turbulence closure models for geophysical boundary layers. A review of recent work. Cont. shelf res. 25: 795-827
  • Umlauf, L. and U. Lemmin (2005). Inter-basin exchange and mixing in the hypolimnion of a large lake: the role of long internal waves. Limnol. oceanogr. 50: 1601-1611
  • Umlauf, L., H. Burchard and K. Bolding (2005). GOTM - Scientific documentation, version 3.2. Warnemünde: Institut für Ostseeforschung. 274 S. (Meereswissenschaftliche Berichte; 63)

2003

  • Umlauf, L. and H. Burchard (2003). A generic length-scale equation for geophysical turbulence models. J. mar. res. 61: 235-265
  • Umlauf, L. and H. Burchard (2003). Reply to "Comments on 'A generic length-scale equation for geophysical turbulence models' " by L. Kantha and S. Carniel. J. mar. res. 61: 703-706
  • Umlauf, L., H. Burchard and K. Hutter (2003). Extending the k-omega turbulence model towards oceanic applications. Ocean model. 5: 195-218

Expertise

Curriculum Vitae

Research

Projects

Teaching

Publications

 

 

Department:

Physical Oceanography

 

working group:

Turbulence and Small-Scale Processes

 

research area:

RA1 (Key Processes Across Scales and Boundaries)

 

Go back