Southern Ocean latent heat flux variability driven by oceanic meso- and submesoscale motions

Corresponding publication (in peer-review) This repository contains the data and analysis codes used in the study reported in: Reymondet, L., Siegelman, L., & Lenain, L.Southern Ocean latent heat flux variability driven by oceanic meso- and submesoscale motions. When using any of the files provided here, please cite both the above article and this Zenodo dataset. Abstract Latent heat flux is a primary pathway for ocean–atmosphere exchange of heat and moisture, yet the influence of sea surface temperature variability at fine scales (≤ 100 km) on latent heat flux variability, particularly over the Southern Ocean, remains poorly understood. Here we quantify the scale-dependent drivers of latent heat flux (LHF) variability using a year-long, global, fully coupled ocean–atmosphere simulation with kilometer-scale resolution. Annual-mean LHF in eddy-rich regions reaches ≈ 215 W/m2, approximately three times larger than in eddy-poor regions. Spectral analyses show that ocean mesoscale [O(100 km)] and submesoscale [O(1–10 km)] variability accounts for up to ≈ 80% of the total LHF variance in eddy-rich sectors, but as little as 10% in eddy-poor regions, and increases proportionally with eddy kinetic energy and sea surface temperature (SST) variance. We also find that strong submesoscale SST fronts (≈ 5°C over 10 km) force a localized secondary circulation that extends well above the marine boundary layer into the mid-troposphere. Comparison with ERA5 shows that fine ocean scales, responsible for about 17% of the ocean-driven LHF variance in the simulation, are largely unresolved in the reanalysis, leading to a muted atmospheric response lacking any secondary circulation. Despite a strong heterogeneity in LHF variability, the atmospheric dynamics are mostly uniform across the domain, suggesting a non local atmospheric response to ocean forcing. These results highlight the potential for ocean meso- and submesoscales, commonly under-resolved in climate models and reanalysis, to influence Southern Ocean air–sea coupling and atmosphere both locally and remotely. Data availability All data used in this study are publicly available. To limit storage requirements, this repository includes only the processed datasets necessary to reproduce the figures presented in the corresponding publication. ERA5 reanalysis data are available from the Copernicus Climate Data Store:http://cds.climate.copernicus.eu/ COAS model outputs are available at:https://portal.nccs.nasa.gov/datashare/G5NR/DYAMONDv2/GEOS_6km_Atmosphere-MITgcm_4km_Ocean-Coupled/ Software and repository contents COAS.zipScripts to download and process COAS model output data. ERA.zipScripts to download and process ERA5 reanalysis data. figures_data.zipProcessed datasets required to reproduce the figures in the publication. plot_figures.zipNotebooks used to generate the figures presented in the publication.