Sanchez-Lorente et al. (2025) Air–sea interaction heat and momentum fluxes based on vessel's experimental observations over Spanish waters

Identification

• Journal: Earth system science data
• Year: 2025
• Date: 2025-10-30
• Authors: A. Sanchez-Lorente, E. Tel, Lucía Sanz-Pinilla, Gonzalo González-Nuevo González
• DOI: 10.5194/essd-17-5729-2025

Research Groups

• Instituto Español de Oceanografía (IEO-CSIC), Servicios Centrales, Madrid, Spain
• Barcelona Supercomputing Center, Barcelona, Spain
• Instituto Español de Oceanografía, Centro Oceanográfico de La Coruña, Spain
• Secretaría General de Pesca of Spain

Short Summary

This paper presents a quality-controlled dataset of air–sea interaction heat and momentum fluxes derived from experimental observations aboard four research vessels over Spanish waters from 2011 to 2023, providing crucial regional data for climate studies and validation of models.

Objective

• To generate and make publicly available a comprehensive, quality-controlled dataset of air–sea interaction heat (sensible and latent) and momentum fluxes based on meteorological and upper-ocean measurements collected by research vessels over Spanish waters and adjacent seas.
• To analyze the spatial distribution and temporal (annual cycle) behavior of these fluxes within various marine-region subdivisions of the Spanish waters.

Study Configuration

• Spatial Scale: Spanish waters and adjacent seas, divided into eight marine regions: North Atlantic, Canary, South Atlantic, Alboran-Strait, Levantine–Balearic, western Mediterranean, Cantabrian–Atlantic, and Atlantic.
• Temporal Scale: 2011–2023 (13 years), with data collected at an hourly frequency.

Methodology and Data

• Models used: Bulk aerodynamic approximation for calculating sensible heat flux (SHFL), latent heat flux (LHFL), and momentum flux (MOFL). Air density calculated using the ideal-gas equation. Specific humidity derived from pressure and relative humidity measurements, incorporating vapor pressure dependency on temperature (Buck, 1981) and a salt concentration factor (0.98). Drag coefficient (CD) based on wind dependency relation (Large and Pond, 1981). Aerodynamic heat (CT) and moisture (C_E) coefficients considered constant (1 × 10⁻³ and 1.3 × 10⁻³, respectively).
• Data sources:
  • Experimental observations from four research vessels: Ramón Margalef (RM), Ángeles Alvariño (AJ), Cornide de Saavedra (CS), and Miguel Oliver (MO).
  • Onboard instrumentation: Vaisala AWS430 meteorological unit and Thermosalinograph (TSG).
  • Variables measured: Air temperature (DRYT), atmospheric pressure (ATMS), wind speed (WSPD), relative humidity (RELH), total incident radiation (RDIN), and sea temperature (TEMP).
  • Data stored in MEDAR/MedAtlas format.
  • Quality control (QC) procedures included visual inspection, global range tests, gradient tests (GT), and spike tests (ST) based on SeaDataNet guidelines.

Main Results

• A publicly available dataset of air–sea interaction heat and momentum fluxes, along with meteorological and TSG variables, for Spanish waters from 2011 to 2023 has been generated and published on SEANOE.
• The dataset comprises 211,713 data rows, with varying percentages of valid data after QC (e.g., atmospheric pressure: 44.6%, sea temperature: 62.7%, relative humidity: 76.5%, air temperature: 77.5%, wind speed: 73.8%).
• Annual cycles for SHFL and LHFL show lowest values during summer (June–August) and highest values during winter (November–December), indicating greater heat loss from the ocean in colder months.
• Sensible Heat Flux (SHFL) annual means are generally positive (e.g., Canary: 9.86 W⋅m⁻², Levantine–Balearic: 6.71 W⋅m⁻²), but the Alboran–Strait region exhibits a negative annual mean of -2.26 W⋅m⁻², consistent with regional cooling processes.
• Latent Heat Flux (LHFL) annual means are higher than SHFL, with peak values in the Canary (138.35 W⋅m⁻²) and Levantine–Balearic (139.50 W⋅m⁻²) regions, reflecting significant evaporation in subtropical and Mediterranean areas.
• Momentum Flux (MOFL) annual means are around 0.1 N⋅m⁻² for all regions, with higher values during winter months due to intensified wind regimes. The Alboran–Strait region shows a slightly higher annual mean of 0.12 N⋅m⁻².
• The data reveal regional disparities in air–sea interaction, such as higher evaporation in the Mediterranean and the influence of trade winds in the Canary region.
• The dataset also includes total incident radiation (RDIN), enabling future studies on the ocean heat budget, though some potential underestimations in RDIN were noted.

Contributions

• Provides a unique, long-term (13 years) observational dataset of air–sea interaction heat and momentum fluxes from research vessels in a heterogeneous region (Spanish waters), which is crucial for regional climate studies.
• Offers valuable in-situ data for the calibration and validation of satellite-based and model-based air–sea flux products, particularly in complex coastal and semi-enclosed sea areas where reanalysis products often exhibit biases.
• Highlights regional differences and annual cycles of air–sea fluxes, contributing to a better understanding of ocean–atmosphere coupling and its variability in the Mediterranean and Atlantic regions.
• The comprehensive dataset, including raw meteorological and TSG variables, supports further research into the ocean heat budget and its components.

Funding

• Instituto Español de Oceanografía (JAE INTRO-ICU fellowship, grant no. JAEICU2301472).
• CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI) for article processing charges.

Citation

@article{SanchezLorente2025Airsea,
  author = {Sanchez-Lorente, A. and Tel, E. and Sanz-Pinilla, Lucía and González, Gonzalo González-Nuevo},
  title = {Air–sea interaction heat and momentum fluxes based on vessel's experimental observations over Spanish waters},
  journal = {Earth system science data},
  year = {2025},
  doi = {10.5194/essd-17-5729-2025},
  url = {https://doi.org/10.5194/essd-17-5729-2025}
}