Melo‐Aguilar et al. (2026) The importance of kilometre-scale SST variability for SST-gradient-driven air–sea coupling in the western Mediterranean

Identification

• Journal: Scientific Reports
• Year: 2026
• Date: 2026-09-25
• Authors: Camilo Melo‐Aguilar, Gabriel Jordá
• DOI: 10.1038/s41598-026-71837-z

Research Groups

• Balearic Islands Coastal Observing System, Palma, Spain
• Centre Oceanogràfic de les Balears (Spanish Institute of Oceanography IEO-CSIC), Palma, Spain

Short Summary

This study assesses the spatiotemporal variability of the downwind sea surface temperature (SST)-gradient diagnostic (γ) in the western Mediterranean, revealing that kilometre-scale SST variability is crucial for strong SST-gradient-driven air-sea coupling and that coarse-resolution SST fields significantly underrepresent these conditions.

Objective

• To assess the spatiotemporal variability of the downwind SST-gradient diagnostic (γ), a proxy for the potential of SST-gradient-driven air-sea coupling, in the western Mediterranean using high-resolution winds and multiple high-resolution SST datasets.
• To quantify the influence of fine-scale SST variability on this coupling potential through spatial filtering experiments.

Study Configuration

• Spatial Scale: Western Mediterranean; kilometre-scale, submesoscale, and mesoscale SST variability.
• Temporal Scale: Spatiotemporal variability, with a focus on climatological imprints of fine-scale SST variability.

Methodology and Data

• Models used: Downwind SST-gradient diagnostic (γ)
• Data sources:
  • High-resolution winds
  • Multiple high-resolution SST datasets, including:
    • E.U. Copernicus Marine Service Information (https://doi.org/10.48670/moi-00169, https://doi.org/10.48670/moi-00168, https://doi.org/10.48670/moi-00172)
    • JPL-MUR data from PO.DAAC (https://doi.org/10.5067/GHGMR-4FJ04)
  • Spatial filtering experiments to quantify the influence of fine-scale SST variability.
  • Sensitivity analysis across different SST products.

Main Results

• Coarsening the SST field substantially reduces the amplitude and extremes of the downwind SST-gradient diagnostic (γ) and weakens its distribution tails.
• Kilometre-scale SST gradients contribute most significantly to the strongest γ conditions, indicating their critical role in air-sea coupling.
• Coarse-resolution SST fields substantially underrepresent the occurrence of diagnostically favourable conditions for SST-gradient-driven coupling.
• A robust climatological imprint of fine-scale SST variability on the γ diagnostic was revealed.
• A sensitivity analysis across SST products showed notable variability in γ magnitude, particularly in frontal regions.
• All datasets consistently identified coherent coupling hotspots associated with persistent mesoscale and submesoscale fronts.

Contributions

• Quantifies the critical importance of kilometre-scale SST variability for accurately representing SST-gradient-driven air-sea coupling in the western Mediterranean.
• Demonstrates the significant underrepresentation of strong coupling conditions when using coarse-resolution SST fields.
• Provides evidence for a robust climatological imprint of fine-scale SST variability on air-sea coupling potential.
• Identifies consistent mesoscale and submesoscale frontal regions as key coupling hotspots across different high-resolution SST datasets.

Funding

• Margarita Salas grant 2021-2023 from the Ministerio de Universidades de España and NextGenerationEU.
• SEAFRONT project (Grant TED2021-132132B-C21) funded by MCIN/AEI/10.13039/501100011033 and the European Union NextGenerationEU/PRTR.

Citation

@article{MeloAguilar2026importance,
  author = {Melo‐Aguilar, Camilo and Jordá, Gabriel},
  title = {The importance of kilometre-scale SST variability for SST-gradient-driven air–sea coupling in the western Mediterranean},
  journal = {Scientific Reports},
  year = {2026},
  doi = {10.1038/s41598-026-71837-z},
  url = {https://doi.org/10.1038/s41598-026-71837-z}
}