Fine-scale Processes and Their Impact on Large-scale Circulation, Heat and Salt Transport, and Water Masses

The objective of WP1 is to understand how fine-scale ocean processes influence large-scale circulation patterns, heat and salt transport, and water mass formation. These processes are key in regulating ocean ventilation and subduction, which control the transfer of heat, gases, and biogeochemical properties from the surface to the deep ocean.

Aim and Methodology:

Fine-scale horizontal and vertical ocean dynamics, driven by advection and mixing, play a crucial role in ocean ventilation and the subduction of water masses. These processes govern the ocean’s ability to absorb and internally transport heat, gases (e.g., CO2), and nutrients, which are critical for climate regulation and marine ecosystem health. To advance our understanding of these dynamics, WP1 employs an innovative approach combining advanced observation techniques and high-resolution modeling.

We aim to characterize the three-dimensional (3D) fine-scale dynamics of the upper kilometer of the ocean and study their evolution over time. This will be achieved through the integration of:

• High-resolution ocean observations and modeling: Utilizing a wide array of platforms and high-resolution satellite data, we will capture fine-scale structures in the upper ocean with unprecedented detail.
• Advanced data science and AI techniques: We will develop automated methods to identify, track, and analyze the temporal and spatial evolution of fine-scale ocean structures (e.g., eddies, fronts, plumes, and jets) using 3D observations and modeling data.
• Model-data fusion: To overcome the limitations of traditional side-by-side comparisons between observations and model outputs, we will develop data-driven approaches to merge model simulations and observational data, improving our ability to detect and analyze ocean fine-scale processes.

Key Outcomes:

Through the multi-decadal simulations conducted within WP1, we aim to quantify the impact of fine-scale dynamics on the large-scale circulation, including:

• Agulhas Leakage and its influence on the Atlantic Meridional Overturning Circulation (AMOC)
• The ventilation of Southern Hemisphere subtropical gyres
• The ocean’s capacity to absorb anthropogenic heat and carbon

WP1 will provide a foundational dataset for the broader WHIRLS project, contributing critical insights to WP2 and WP3 by defining the 3D structure and evolution of fine-scale ocean processes. This knowledge will be essential for improving the accuracy and realism of future Earth system models, ultimately enhancing our ability to predict climate change impacts.