On the fast atmospheric response to mesoscale sea surface thermal structures in the Mediterranean Sea
Agostino N. Meroni
Séminaire hebdomadaire du LMD à l’ENS.
Sea surface temperature (SST) spatial variability is known to impact the overlying atmospheric dynamics over a wide range of spatio-temporal scales through two main mechanisms. The first mechanism involves the downward mixing of horizontal momentum over unstable warm SST patches, resulting in the generation of surface wind convergence over SST fronts. The second mechanism is mediated by the pressure adjustment to the SST structure, that produces wind convergence over SST maxima.
By looking at 25 years of satellite observational products and reanalysis data, we study the long-term effects of the fast air-sea interactions (on daily and sub-daily scales) over the Mediterranean Sea. We find that the presence of strong SST gradients produces a statistically significant response in terms of surface wind convergence, cloud cover and precipitation. Ongoing work on the definition of some new metrics to detect the pressure adjustment mechanism in instantaneous wind field data will also be presented.
Le séminaire tiendra au Département de Géosciences de l’ENS – salle Lien Hua / E350 – 24, rue Lhomond – 75005 Paris.