Copernicus Marine and SOCIB join efforts and capabilities to assess extreme events

Collaborative research led by Puertos del Estado, involving the participation of the Balearic Islands Coastal Observing and Forecasting System (SOCIB) and other national interdisciplinary and inter-sectoral institutions, assesses the impacts of the record-breaking Storm Gloria (January 19–24, 2020) from different perspectives using Copernicus Marine Environment Monitoring Service (CMEMS) and SOCIB capabilities. This work, published in the journal Frontiers in Marine Science, helps to outline future Service upgrades aimed at better forecasting extreme metocean events at coastal scales.

Natural disasters might impose significant and long-lasting pressures on coastal ecosystems, resulting frequently in the degradation of marine protected areas. Equally, their destructive effects on human infrastructures may disrupt essential services, damage economical assets, and even cause casualties, especially in densely populated urban coastal areas. Therefore, the accurate monitoring, understanding, and prediction of natural weather-related hazards is not only crucial to prompt a wealth of anticipatory adaptation strategies but also of great economic value for the maritime sector. Such preventive approaches can aid to mitigate devastating effects and, eventually, strengthen community resilience at multiple scales, and are at the heart of the new green deal EU initiatives.

Gloria on January 19 at noon, with its center located between Ibiza and cabo de la Nao (MODIS image from the SUOMI-NPP satellite).

Gloria on January 19, 2020, at noon, with its center located between Ibiza and Cabo de la Nao (MODIS image from the SUOMI-NPP satellite).

According to researchers, this is particularly the case for the Storm Gloria (January 19–24, 2020), the 10th named storm in Europe for the 2019-2020 winter season, that severely affected eastern parts of Spain and France. Storm Gloria hit the North-Western Mediterranean Sea with heavy rainfall, strong easterly winds, and very high waves, causing structural damages and 13 fatalities. In particular, the low-lying Ebro Delta region was severely inundated, ruining rice fields and seaside promenades. A team of researchers led by Puertos del Estado have analysed this extreme event from different perspectives - sea level, waves, High Frequency (HF) radar currents, and numerical modelling, the last two involving the collaboration of SOCIB. This work has been published in the journal Frontiers in Marine Science, as part of the Research topic on Coastal Extension of CMEMS Products. Models, Data and Applications.

“This powerful storm represents an excellent case study to analyze the capabilities of the different HF radar products and ocean forecasting systems available in the Spanish Mediterranean coasts to simulate extreme events, as well as to assess their suitability to enhance preparedness in maritime disasters with high impacts on coastal areas,” as stated by the researchers. To that end, five operational ocean forecasting services (delivered by CMEMS, SOCIB and Puertos del Estado), including the WMOP system developed by SOCIB, have been used to examine the fingerprint of Gloria and the upper and deep ocean response.

According to the results, “Gloria can be interpreted as a high-impact once-in-a-decade meteorological and oceanographic (metocean) event where various historical records were beaten,” the scientists' highlight. “The 99th percentile of several parameters (wind speed, significant wave height, wave period, and surface current velocity), derived from long-term observational time series, was persistently exceeded, also when compared with a previous extreme event that occurred in January 2017,” they add.

Researchers have quantified the ability of the HF radar from the Ebro Delta to characterize waves and currents under the extreme event. “Gloria's remote-effect in adjacent choke-points of the North Western Mediterranean Sea was evidenced by means of the anomalous surface circulation patterns measured by the HF radar systems of the Ibiza Channel and the Strait of Gibraltar,” they explain. “The impact of Gloria caused a large increase in the kinetic energy and a significant deepening of the mixed layer depth, as derived from the CMEMS Iberia-Biscay-Ireland (IBI) hydrodynamic model. Comparison of this model vs. HF radar surface currents highlight the limitations of the former to correctly reproduce the wave-current interactions and the Ebro river runoff in this particular extreme event,” they conclude.

Furthermore, scientists have also evaluated the skill of five operational ocean forecasting services to reproduce the storm-induced ocean circulation using observations as a benchmark to compare with. The results assess the performance of the dynamical downscaling at two different levels: first, within the own CMEMS service (with their regional products, as enhanced solutions with respect to the global one) and second in the coastal down-streaming service side (with very high-resolution models reaching coastal scales, including the SOCIB-WMOP with a horizontal resolution of roughly 2 km, and the PdE SAMOA systems with a 350-m resolution that cover coastal domains of the Spanish Port Authorities of Barcelona, Tarragona, Castellón and Almeria). “This multi-model study case focused on Gloria has allowed us to identify some strengths and limitations of the systems currently in operations, and it can help to outline future model service upgrades aimed at better forecasting extreme coastal events,” as stated by the authors.

Reference articles

Lorente P, Lin-Ye J, García-León M, Reyes E, Fernandes M, Sotillo MG, Espino M, Ruiz MI, Gracia V, Perez S, Aznar R, Alonso-Martirena A and Álvarez-Fanjul E (2021). On the Performance of High Frequency Radar in the Western Mediterranean During the Record-Breaking Storm Gloria. Frontiers in Marine Science, 8:645762. DOI: 10.3389/fmars.2021.645762

Sotillo MG, Mourre B, Mestres M, Lorente P, Aznar R, García-León M, Liste M, Santana A, Espino M and Álvarez E (2021). Evaluation of the operational CMEMS and coastal downstream ocean forecasting services during the storm Gloria (January 2020). Frontiers in Marine Science, 8:644525. DOI: 10.3389/fmars.2021.644525