SPRING 2025
Wednesdays at 3:00 pm, Seminar Room SLAB 103 / Virtual SLAB 103
(unless stated otherwise)
Jan 08 (2:45 pm): Dr. Sophia Brumer
Aerology Laboratory (LAERO), Toulouse, France
Guest of Milan Curcic, Department of Ocean Sciences
On Sub-Mesoscale Air-Sea Interactions in Extratropical Windstorms
Recording Available at COMPASS ON DEMAND
Windstorms associated with extratropical cyclones are destructive natural hazards. We are interested in elucidating the processes involved in the formation of near-surface extreme winds, and my focus is on wave and wave-breaking related processes. Though crucial for their societal impact, these processes are not well understood and too small-scale to be explicitly represented in numerical weather prediction models. Waves modulate air-sea exchanges, mix the upper ocean, and inject sea spray into the atmosphere when breaking. Air-sea fluxes of enthalpy and momentum greatly influence the dynamics of the marine atmospheric boundary layer (MABL). Waves increase the surface roughness but sea spray loading may act as a buffer layer reducing drag and stabilizing the MABL. Larger droplets increase air-sea enthalpy and decrease momentum transfers, thus promoting the intensification of tropical cyclones, but what of extratropical cyclones?
In this talk, I will give an overview of ongoing and planned work at the Laboratoire d'Aérologie (LAERO) in Toulouse, France, on sub-mesoscale ocean-wave-atmosphere interactions in extratropical cyclones. Ongoing work will be illustrated through three case studies: 1) the Mediterranean cyclone Adrian, where sub-mesoscale wind rolls show strong sensitivity to air-sea fluxes; 2) the North Atlantic storm Alex, where wave coupling influences mesoscale jets and the downward momentum transport; and 3) the cold wake producing medicane (Mediterranean Hurricane) Ianos, where the ocean induces a negative feedback similar to that seen in certain tropical cyclones.
Future work aims at establishing a coherent air-sea coupled framework for numerical weather predictions, which includes the impact of waves on roughness, of sea spray on the MABL, and takes into account relative alignment between the wind and wave systems. For this purpose, we are designing realistic coupled simulations with horizontal resolutions approaching those of Large Eddy Simulations. These will allow gauging the scale of impacts of non-resolved and poorly constrained processes, such as sea spray generation and subsequent heat and momentum exchanges within the MABL. Field measurements needed to evaluate these simulations will include the NAWDIC field campaign, which will sample North Atlantic storms over the winter of 2025/2026. Future campaigns in the Mediterranean / Ionian Sea and the south Indian Ocean are also under consideration.
Sophia Brumer is a CNRS researcher specialized in ocean-wave-atmosphere interactions at the Aerology Laboratory (LAERO) in Toulouse, France. She obtained her BSc degree from the University of Miami and her PhD from Columbia University, where she investigated the role of waves and wave breaking on air-sea gas transfer based on shipborne measurements. She then joined the Laboratoire d’Océanographie Physique et Spatiale (LOPS, Brest, France) for a series of postdocs revolving around the role of waves on an ocean tidal temperature front and the impact of sea spray on the marine atmospheric boundary layer using coupled models. Since September 2023, she is at the LAERO where her work seeks to understand and quantify the role of sea state, wave breaking, and sea spray on wind and rain extremes in low-pressure systems.
Jan 15: NO SEMINAR
Jan 22: Dr. Alina Nathanaël Dossa
Department of Ocean Sciences, Rosenstiel School
Global Analysis of Coastal Gradients of Sea Surface Salinity
Sea surface salinity (SSS) is a key variable for ocean-atmosphere interactions and the water cycle. Due to its climatic importance, increasing efforts have been made for its global in-situ observation, and dedicated satellite missions have been launched more recently to allow homogeneous coverage at higher resolution. Cross-shore SSS gradients can bear the signature of different coastal processes such as river plumes, upwelling, or boundary currents, as we illustrate in a few regions. However, satellite performances are questionable in coastal regions. Here, we assess the skill of four gridded products derived from the Soil Moisture Ocean Salinity (SMOS) and Soil Moisture Active Passive (SMAP) satellites and the GLORYS global model reanalysis at capturing cross-shore SSS gradients in coastal bands up to 300 km wide. These products are compared with thermosalinography (TSG) measurements, which provide continuous data from the open ocean to the coast along ship tracks. The comparison shows various skills from one product to the other, decreasing as the coast gets closer. The bias in reproducing coastal SSS gradients is unrelated to how the SSS biases evolve with the distance to the coast. Despite limited skill, satellite products generally agree better with collocated TSG data than a global reanalysis and show a large range of coastal SSS gradients with different signs. Moreover, satellites reveal a global dominance of coastal freshening, primarily related to river runoff over shelves. This work shows a great potential of SSS remote sensing to monitor coastal processes, which would, however, require a jump in the resolution of future SSS satellite missions to be fully exploited.
Jan 29: SPECIAL ATM & OCE FACULTY PRESENTATION SERIES
Dr. Mariana Bernardi Bif
Department of Ocean Sciences, Rosenstiel School
Feb 05: AVAILABLE
Feb 12: Yixin "Berry" Wen
Department of Geography, University of Florida, Gainesville
Feb 19: NO SEMINAR (SLAB 103 not available)
Feb 26: Elizabeth Yanuskiewicz
Department of Ocean Sciences, Rosenstiel School
(one-hour OCE student seminar)
Mar 05: Hope Elliott
Department of Atmospheric Sciences, Rosenstiel School
(one-hour OCE student seminar)
Mar 12: NO SEMINAR (Spring Recess)
Mar 19: Dr. Lorenzo Polvani
Department of Applied Physics and Applied Mathematics, Columbia University, New York
Guest of Brian Soden, Department of Atmospheric Sciences
Mar 26: Victoria Schoenwald
Department of Atmospheric Sciences, Rosenstiel School
(one-hour ATM student seminar)
Apr 02: Samantha Medina
Department of Ocean Sciences, Rosenstiel School
(one-hour OCE student seminar)
Apr 09: Karen Papazian
Department of Atmospheric Sciences, Rosenstiel School
(one-hour ATM student seminar)
Apr 16: Dr. Milan Curcic
Department of Ocean Sciences, Rosenstiel School
A Theoretical Model for Wave Tearing by Wind
Apr 23: AVAILABLE
