Oceans and coastal zones
Oceans, especially the upper oceans , play key roles on the earth climate regulation (e.g., climate change) as well as for human societies. Despite the ever-increasing development of simulation and observation capabilities leading to earth observation big data, our ability to understand, reconstruct and forecast upper ocean and marine atmospheric boundary layer dynamics remains fairly limited for numerous processes.Surprisingly, data characterizing the air-sea interactions at the ocean interface are not used for TC intensity estimates and forecasts. However, a new generation of space-borne sensors able to probe the ocean surface through clouds has emerged ((e.g. Reul et al. 2012, Zhang et al., 2012). In addition, there is also a wealth of non-local information related to TC that can be analyzed to fully characterize the TC intensity and its coupling with the oceans. Indeed, associated with TC extreme wind forcing conditions, quite systematically persistent signatures in TC wake can also be observed. A TC induces vigorous mixing and intense upwelling that generally result in a cooling of the upper ocean mixed layer [Ginis, 2002] and an important displacement of isopycnals [Geissler, 1970], characterized by prominent sea-surface height anomalies in their wake. Swell systems are also fingerprints of extreme ocean storms, and can propagate all the way across ocean basins from the area of high winds that generated them. Very long-period swells have been observed to propagate up to halfway around the globe [e.g. Munk et al., 1963]. Data acquired at different times and locations can thus be gathered to document a given extreme event. This proposal focuses on the interactions between ocean and atmosphere in the case of TC and Extra-Tropical Cyclones (ETC). Main scientific objectives are to develop data-model-driven techniques dedicated to extreme marine-atmosphere events, to provide new insights for air-sea exchanges processes parameterization under extreme conditions, and to drive the specifications of new generation of observation networks for TC monitoring. The project also aims at training young scientists. It includes three PhD students and will elaborate new material for a new tutorial on the benefit of adopting a multi-modal approach to characterize Tropical and Extra-Tropical Cyclones. The tutorial will rely on case studies extracted from the CyclObs database, a specific database for cyclones developed during the project.European team is funded through CNES IWWOC and COWS projects aiming at promoting the use of CFOSAT and ESA Sentinel-1 MPC and SMOS projects focusing on SMOS and Sentinel-1 missions. Chinese team is funded by National Key R&D program of China under Grant 2016YFC1401001.
