Importance of ocean-atmosphere coupling on the sensitivity to climate change - Impact on hurricanes.

• Main Author: DALOZ, Anne Sophie
• Other Authors: Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse III, Frank Roux et Fabrice Chauvin
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2011
• Subjects: Hurricanes; ocean-atmosphere coupling; regional modeling; climate change; Ouragans; couplage océan-atmosphère; modélisation régionale; changement climatique; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; North Atlantic
• Online Access: https://tel.archives-ouvertes.fr/tel-01152013; https://tel.archives-ouvertes.fr/tel-01152013/document; https://tel.archives-ouvertes.fr/tel-01152013/file/These_Daloz.pdf

Ocean-atmosphere interactions are essential for tropical cyclones. The ocean provides the energy required to sustain tropical cyclones. The simulation of interactions between the ocean and tropical cyclones is therefore crucial and is the focus of this thesis.The first section introduces the rotated-stretched and coupled version of the general circulation model ARPEGE-Climate, developed for this thesis. This rotated-stretched version achieves a spatial resolution between 60 and 100 km over the North Atlantic basin, resolution required to study tropical cyclones. The coupling of ARPEGE-Climate with oceanic general circulation model NEMO has also allowed taking in consideration ocean-atmosphere of tropical cyclones. Two types of simulations are performed, on the one hand coupled simulations and on the other hand simulations with prescribed sea surface temperatures from the coupled simulation.The second section focuses on the ability of general circulation models from the Intercomparison program, TC-MIP, to represent tropical cyclone activity and its precursors on the main development region of the North Atlantic Ocean. General circulation models have strong difficulties to represent tropical cyclone activity in this region, certainly related to their low spatial resolution, between 1° and 2.5°. Although, the following precursors of tropical cyclone activity have been identified in this region :• African easterly waves activity,• Sahelian rainfall and especially those that occurs over the Fouta-Djallon, 11 ° N,•sea surface temperatures and vertical wind shear horizontal on the main development region,• tropospheric humidity over the African west coast.The third section of the thesis presents sensitivity tests that were performed on ARPEGE-Climate rotated-stretched and coupled with NEMO. These tests show the importance of the stretching pole position, the setting of the convection scheme parameters and the coupling frequency.In the fourth section, the configurations of ARPEGE-Climate coupled and forced are compared ...