MEDICANES

What Are Medicanes?

The term "medicane," short for “Mediterranean hurricane,” was introduced two decades ago to describe vortices similar to tropical cyclones, occurring in the Mediterranean region. Although medicanes rarely match the intensity of tropical cyclones, they can still cause significant damage through windstorms, floods, and storm surges. Affecting over 500 million people in one of the world's most densely populated regions, medicanes represent a significant environmental risk.

The Science Behind Medicanes

Research suggests that medicanes are sustained by a feedback loop between surface enthalpy fluxes and wind, akin to tropical cyclones. This has led to the broadly accepted view that medicanes are a distinct type of Mediterranean cyclone sharing many physical processes with tropical cyclones. Both exhibit similar features such as weakening after landfall, warm-core structures, weak environmental wind shear, and a decrease in the number of lightning flashes near the center at maturity. However, recent studies have shown that not all cyclones classified as medicanes develop through the same mechanisms as tropical cyclones, as baroclinic instability (typical of common mid-latitude cyclones) may play an important role even in the mature stage.

Defining Medicanes

A major challenge within the scientific community has been the lack of a consistent definition for medicanes. Different criteria used in research and observations have led to varying definitions, making it difficult to compare findings across studies. This inconsistency also complicates the issuance of weather warnings, leading to confusion among weather services and the public.

A New Definition for Medicanes

To address this issue, the MEDICANES project has recently introduced a standardized definition:

"A medicane is a mesoscale cyclone that develops over the Mediterranean Sea and displays tropical-like cyclone characteristics: a warm core extending into the upper troposphere, an eye-like feature in its center with spiral cloud bands around, an almost windless center surrounded by nearly-symmetric sea-surface wind circulation with maximum wind speed within a few tens of km from the center."

This phenomenological definition, based on observable structural characteristics, ensures objectivity and consistency in identifying medicanes. The use of Earth Observations (EOs) allows for equal accessibility and reproducibility in models, enhancing collaboration among weather services for issuing accurate warnings. The paper including the definition of medicane has been recently published in the Bulletin of the American Meteorological Society:

Miglietta M. M., Flaounas E., González-Alemán J. J., Panegrossi G., Gaertner M. A., Pantillon F., Pasquero C., Schultz D. M., D’Adderio L. P., Dafis S., Husson R., Ricchi A., Carrió D. S., Davolio S., Fita L., Picornell M. A., Pytharoulis I., Raveh-Rubin S., Scoccimarro E., Bernini L., Cavicchia L., Conte D., Ferretti R., Flocas H., Gutiérrez-Fernández J., Hatzaki M., Homar Santaner V., Jansà A., Patlakas P., Defining Medicanes: Bridging the Knowledge Gap Between Tropical and Extratropical Cyclones in the Mediterranean, BAMS, https://doi.org/10.1175/BAMS-D-24-0289.1