Bulk Fluxes in Earth System Models and Beyond: How converging scales may lead to diverging results

Momme Hell

NSF NCAR Advanced Studies Program

Tuesday, Mar 12, 2024, 2:00 pm MT Add to Calendar
DSRC Room 2A305

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Abstract

Air-sea coupling is a major challenge in the next generation of earth system modeling. The increasing evidence of strong coupling at the air-sea interface on small scales raises the question of how those processes are represented in the upcoming generation of high-resolution coupled models.

All coupled model approaches rely on bulk-fluxes parametrization based on assumptions of the Monin-Obukhov Similarity Theory. These flux parametrizations are traditionally identified as a source of model error, often ignoring that the combination of multiple parametrizations in the atmosphere, ocean, and sea ice constitute the model representation of the air-sea interface. Hence, even though turbulent fluxes are the mechanism through which the coupling is computed, their formulation is by no means the only reason for biases in the atmosphere and ocean boundary layer.

This talk will discuss challenges in air-sea exchange for the next generation of coupled models and the potential role of explicitly resolved surface waves.

We will first review assumptions of bulk-fluxes parametrization and then outline their potential deficits given recent results from models and observations. Finally, it will outline potential avenues to comprehend, analyze, and model scale-aware air-sea exchange through a strongly coupled boundary layer system under the presence of waves.