The University of Melbourne is pleased to host the next

AIR-SEA INTERFACE Wave Dynamics, Turbulence, Acoustics, Remote Sensing

incorporating the 6th Workshop on Waves and Wave-Coupled Processes

Air-Sea-Interface meetings were a series of symposia in the late 20th century, an undisputed success among metocean researchers. They brought together wave, oceanographic and meteorological communities, experts in radio and acoustic remote sensing of interface, but were discontinued after the 1999 ASI in Sydney.

The 2025 ASI Symposium aims to restart the convention. In addition to the traditional topics, it will accommodate 21st century new fields in the ASI research: coupled air-wave-sea-ice systems, metocean climatology, satellite remote sensing of the ocean interface.

Keynote Speakers:

AL OSBORNE, Nonlinear Wave Research Corp.

Scientific contributions of Vladimir Zakharov: From the Past to the Future

Vladimir Zakharov was one the greatest mathematical physicists of the 20th and early 21st centuries. He developed the Zakharov equation for the nonlinear evolution of water waves, based primarily on the modulational instability band of the Euler equations. He was an early pioneer of the inverse scattering transform which eventually allowed the analytical integration of an entire infinite class of nonlinear wave (soliton) equations. He developed the field of weak wave turbulence which has allowed the study of random waves to a depth never before imagined. He also did work in general relativity, in quantum mechanics and other areas of mathematical physics. We shall in this talk discuss the major accomplishments in water waves and the solution of nonlinear partial differential equations. Given enough time I will also discuss some of his work on quasiperiodic and almost periodic solutions of nonlinear pdes, which portends an exciting future for the study of nonlinear waves: Our understanding of water waves will be hugely enhanced in our lifetimes and beyond.

MILAN CURCIC, University of Miami, USA.

Everything you wanted to know about spectral wave models but were afraid to ask

Phase-averaged spectral wave models are modern, computationally efficient methods for predicting the distribution of ocean surface waves across scales—from lakes and estuaries to global swell patterns. Rather than solving for the elevation at scales smaller than individual waves, as phase-resolved models do, spectral wave models predict a probability distribution of wave action in frequency-direction space at each geographical location. These models are run operationally by national centers around the world in support of marine safety and operations, coastal infrastructure, remote sensing interpretation, and more.

In this talk, we will review (a) the history behind modern third-generation wave models; (b) how they work under the hood; and (c) the state-of-the-art of wave model source functions, which continue to improve to this day. After the review, we will explore practical applications of the University of Miami Wave Model, designed for easy coupling with weather and ocean circulation models. I will conclude with a personal outlook on spectral wave models in the context of current scientific and technological frontiers: (1) momentum-conserving wind-wave-current coupling; (2) emerging heterogeneous hardware architectures; and (3) machine learning methods to emulate and accelerate spectral.

MARC BUCKLEY, Helmholtz Zentrum Hereon, Germany
Influence of wind-wave interactions on air-sea fluxes of momentum and energy

The exchanges of momentum and scalars across the ocean surface are controlled by small-scale dynamics within the first millimeters to meters of the coupled atmospheric and oceanic wave boundary layers. While several theories and parametrizations exist, our understanding of the exact role of waves in air-sea exchanges of momentum and energy remains incomplete. This is, to a large degree, due to the technical difficulty in achieving direct observations of turbulent airflow dynamics within the marine atmospheric wave boundary layer, especially in the immediate vicinity of the highly dynamic, wavy ocean surface. Theoretical and computational approaches are equally challenging, due to the complexity of this multiphase, turbulent flow problem, that involves complex feedback mechanisms in a range of spatial and temporal scales. After providing a brief overview of existing theories and parametrizations of wave-mediated energy and momentum fluxes, we will review recent advances and challenges in the observation of airflow dynamics above water surface waves, in the field and in the laboratory. Attention will be given to the influence of waves on the partitioning of momentum and energy budgets between turbulent and wave-growth contributions. These budgets are strongly affected by several wind-wave parameters, including wind speed, atmospheric stability, wave age, slope, wind-wave alignment, to name a few. For example, slow, strongly wind-forced, steep waves will lead to airflow separation (sheltering), while waves that travel faster than the near surface wind, may induce orbital motions in the airflow. Finally, implications for wind-wave energy exchange mechanisms, as well as for bulk drag law parameters (e.g., drag coefficient, aerodynamic roughness) will be discussed.

CHRIS ZAPPA, Colombia University, USA

Surface Waves and Dynamics of the Upper Ocean

The exchanges of momentum and scalars across the ocean surface are controlled by small-scale dynamics within the first millimeters to meters of the coupled atmospheric and oceanic wave boundary layers. While several theories and parametrizations exist, our understanding of the exact role of waves in air-sea exchanges of momentum and energy remains incomplete. This is, to a large degree, due to the technical difficulty in achieving direct observations of turbulent airflow dynamics within the marine atmospheric wave boundary layer, especially in the immediate vicinity of the highly dynamic, wavy ocean surface. Theoretical and computational approaches are equally challenging, due to the complexity of this multiphase, turbulent flow problem, that involves complex feedback mechanisms in a range of spatial and temporal scales. After providing a brief overview of existing theories and parametrizations of wave-mediated energy and momentum fluxes, we will review recent advances and challenges in the observation of airflow dynamics above water surface waves, in the field and in the laboratory. Attention will be given to the influence of waves on the partitioning of momentum and energy budgets between turbulent and wave-growth contributions. These budgets are strongly affected by several wind-wave parameters, including wind speed, atmospheric stability, wave age, slope, wind-wave alignment, to name a few. For example, slow, strongly wind-forced, steep waves will lead to airflow separation (sheltering), while waves that travel faster than the near surface wind, may induce orbital motions in the airflow. Finally, implications for wind-wave energy exchange mechanisms, as well as for bulk drag law parameters (e.g., drag coefficient, aerodynamic roughness) will be discussed.

ZHENYA SONG, First Institute of Oceanography, China.

Effects of ocean surface waves in the large-scale air-sea-wave-ice coupled system

Although ocean surface waves constitute an important part of the Earth climate system proposed by Hasselmann in 1991, the role of waves has not been considered because it is believed that waves are small-scale motions and do not play a significant role in the large-scale air‒sea‒wave‒ice coupled system. Recently, the critical roles of waves in the ocean, air‒sea interactions, and climate systems have received increasing attention. By incorporating the ocean surface wave model into the Earth system model (ESM) through the role of waves in ocean vertical mixing and air–sea fluxes, two generations of FIO-ESM were innovatively developed by the First Institute of Oceanography (FIO), which can effectively reduce simulation biases. Focusing on the effects of waves on the climate system, this review focuses on the background and history of two-generation FIO-ESM development by introducing four distinctive physical processes, including wave-induced vertical mixing, the air‒sea flux induced by Stokes drift, the heat flux associated with sea spray, and the sea surface temperature (SST) diurnal cycle scheme. Moreover, the future development and suggestions of the ESM are also discussed from the perspective of the role of ocean surface waves on the ESM.

Program themes:

1. Nonlinear Dynamics of Surface Waves (in name of Vladimir Zakharov)

Understanding the nonlinear dynamics of the surface waves links fundamental fluid mechanics and geophysical applications of the other sections in the Program. Papers are encouraged on the full spectrum of phase-resolving research of surface waves: analytical theory, direct wave modelling, including wave-turbulence, wave-current, wave-ice, wind-wave interaction models, laboratory studies and field observations of the ocean waves. Specific topic of interest, gaining momentum and significance lately, is the research of infragravity waves.

The Session also intends to commemorate Vladimir Zakharov who was one of the greatest wave scientists of the last 50 years. Unfortunately, he died last year and it is with great sadness that we are unable to have him attend and speak at the meeting in Melbourne. For this and many other reasons we have decided to celebrate his life’s work and its impact on our field and to make attempts to extrapolate his work into the future. Particular aspects of this Session will address the original work to derive the Zakharov equation and the associated kinetic equation. The solutions of the equation will also be addressed, including weak wave turbulence that have been discovered theoretically, found numerically and verified experimentally. Many other aspects of Zakharov’s work will be addressed in the experimental domain, where methods for the discovery of coherent structures in the wind and waves in the air-sea-interface will be welcome. Connection of the Zakharov equation to the wind for phase resolving models will also be a topic of importance.

2. Spectral Wave Modelling

This section aims at advancement of phase-average models, particularly those used for wave forecast (such as WW3, WAM, SWAN), research and in air-sea-ice coupled systems. Encouraged are presentation of the main missing or poorly understood physics for such models: directional spread of main source functions, i.e. wind input and dissipation terms, prediction of amplitude and arrival time of swell, wave-current interactions, diffraction. Main numerical outstanding issues are the explicit computations of full nonlinear integral and other advances of the nonlinear source terms, and overall reduction of computational time needed for coupling wave models with large scale earth systems, including climate models. With respect to the coupling efforts, the critical outputs by the wave models is the dynamic fluxes of energy and momentum, supported by waves on both sides of the interface, as well as in the marginal ice zone.

3. Air-Sea Fluxes in the Atmospheric Boundary Layer (incorporating the 6th Workshop on Wave-Coupled Processes)

This session aims at the full spectrum of wave-coupled effects on the atmospheric side of the interface, including extreme conditions. These involve wave-supported dynamic fluxes of energy and momentum (including the problems of drag coefficient and surface roughness, misalignment of wind and wave stresses in developing and developed seas, tropical and extratropical cyclones, swell conditions), moisture and gas fluxes, latent and heat fluxes, including the spray and aerosol production. Important topic is the ability of wave-coupled environments to describe Wave Boundary Layer and three-dimensional wind profile near the surface in swell and regular conditions, and in extreme metocean conditions.

4. AS Fluxes and Metocean dynamics in the upper ocean (incorporating the 6th Workshop on Wave-Coupled Processes)

The wave-coupled effects on the ocean side have been overlooked for decades and are now a subject of close attention of the metocean community and rapid developments from theoretical and experimental perspectives, including phase-resolving and phase-average numerical modelling, laboratory and in situ observations. Encouraged are presentations on wave-induced turbulence and mixing, including wave-breaking turbulence and depth-distributed turbulence due to wave orbital motion, wave stresses on the ocean side and air-sea momentum/energy flux balance in presence of waves, wave-induced three-dimensional dynamics (Stokes drift, radiation stress, wave-breaking scattering), and their proportion and misalignment with respect to the wind stress and wind drift.

5. Coupled Air-Wave-Sea-Ice Systems and Wave Climatology (incorporating the 6th Workshop on Wave-Coupled Processes)

While in the recent past marine geophysical phenomena were subdivided into separate groups according to their scales, i.e. turbulence, wind waves, weather, ocean circulation, climate, it is rapidly becoming clear that many large-scale geophysical processes are essentially coupled with the surface waves, and those include climate, marine weather, tropical cyclones, marginal ice zone and other phenomena in the atmosphere and many issues of the upper-ocean physics and chemistry below the interface. Understanding of the complex dynamics and thermodynamics of such coupled systems is greatly facilitated by the accelerating advances of computing capabilities which allow us to employ coupled systems of models for very different geophysical scales. Contributions are encouraged on wave-coupled effects in the lower atmosphere, and upper ocean, including topics of internal waves, sea ice, CO2 and other gas exchanges, biogeochemistry.

6. Turbulence, Bubbles, Acoustics, and Sea Surface Remote Sensing

We encourage submissions which address at least one of four possible topics:

Turbulence: Topics include atmospheric and ocean turbulence, its role in air-sea interactions and fluxes, ocean mixing, transport of admixtures such as nutrients in the water or aerosols in the air, among others.

Bubbles: This includes bubble generation studies, prediction or measurement of bubble plumes or bubble size distributions, and practical effects of bubbles, such as acoustic propagation losses.

Acoustics: Possible topics include any acoustic processes which are clearly connected to air-sea interactions, such as ambient noise from breaking waves, or microseisms generated by surface waves.

Remote sensing: Submissions may discuss uses of remote sensing relevant to ocean waves and air-sea interaction, broadly including ship or ground-based radars, and measurement by aircraft or satellite. Specific topic of interest: applications related to the use of SWOT mission for studies of ocean waves.

ORGANISING COMMITTEE:

Co-chairs:
Prof. Alexander Babanin, University of Melbourne
Prof. Al Osborne, Nonlinear Waves Research Corp

Members:
Jean Bidlot (UK), Gary Brassington (Australia), Luigi Cavaleri (Italy), Amin Chabchoub (Japan), Johannes Gemmrich (Canada), Vladimir Kudryavtsev (Russia), Will Drennan (USA), Miguel Onorato (Italy), Fangli Qiao (China), Don Resio (USA), Erick Rogers (USA), Yulia Troitskaya (Russia), Joey Voermans (Australia), Takuji Waseda (Japan), Lichuan Wu (Sweden), Ian Young (Australia), Seth Zippel (USA)

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REGISTRATION FEES:

Registration fee includes ALL morning and afternoon teas and icebreaker event on Sunday 12 January

General registration - $550.00 plus booking fee and credit card charges

CONFERENCE ACCOMMODATION:

We have received a discounted hotel rate of AU $195 (including breakfast) for the first 20 participants at the Best Western Plus Travel Inn Hotel, Cnr. Grattan & Drummond Sts., Carlton. Web: http://www.thetravelinn.com.au.

The hotel is located in close proximity to the University of Melbourne conference venue.

In order to receive the discounted rate, send a reservation email to res@travelinn.net.au (Attention: Shannon) and quote #103437.

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Contact the host of AIR-SEA INTERFACE Wave Dynamics, Turbulence, Acoustics, Remote Sensing Conference

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