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Dutheil, C.; Lengaigne, Matthieu; Bador, M.; Vialard, J.; Lefèvre, J.; Jourdain, N. C.; Jullien, Swen; Peltier, A.; Sultan, B.; Menkès, C.. |
Climate model projections generally indicate fewer but more intense tropical cyclones (TCs) in response to increasing anthropogenic emissions. However these simulations suffer from long-standing biases in their Sea Surface Temperature (SST). While most studies investigating future changes in TC activity using high-resolution atmospheric models correct for the present-day SST bias, they do not consider the reliability of the projected SST changes from global climate models. The present study illustrates that future South Pacific TC activity changes are strongly sensitive to correcting the projected SST changes using an emergent constraint method. This additional correction indeed leads to a strong reduction of the cyclogenesis (−55%) over the South Pacific... |
Tipo: Text |
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Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00614/72648/71651.pdf |
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Dutheil, Cyril; Bador, M.; Lengaigne, M.; Lefèvre, J.; Jourdain, N. C.; Vialard, J.; Jullien, Swen; Peltier, A.; Menkes, C.. |
The South Pacific Convergence Zone (SPCZ) is poorly represented in global coupled simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5), with trademark biases such as the tendency to form a “double Intertropical convergence zone” and an equatorial cold tongue that extends too far westward. Such biases limit our confidence in projections of the future climate change for this region. In this study, we use a downscaling strategy based on a regional atmospheric general circulation model that accurately captures the SPCZ present-day climatology and interannual variability. More specifically, we investigate the sensitivity of the projected rainfall response to either just correcting present-day CMIP5 Sea Surface Temperature (SST) biases or... |
Tipo: Text |
Palavras-chave: Regional climate models; South Pacific Convergence Zone; Precipitation; Sea Surface Temperature. |
Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00484/59603/62636.pdf |
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Samson, G.; Masson, S.; Lengaigne, M.; Keerthi, M. G.; Vialard, J.; Pous, Stephane; Madec, G.; Jourdain, N. C.; Jullien, Swen; Menkes, C.; Marchesiello, P.. |
This paper presents the NOW regional coupled ocean-atmosphere model built from the NEMO ocean and WRF atmospheric numerical models. This model is applied to the tropical Indian Ocean, with the oceanic and atmospheric components sharing a common 1/4 degrees horizontal grid. Long experiments are performed over the 1990-2009 period using the Betts-Miller-Janjic (BMJ) and Kain-Fritsch (KF) cumulus parameterizations. Both simulations produce a realistic distribution of seasonal rainfall and a realistic northward seasonal migration of monsoon rainfall over the Indian subcontinent. At subseasonal time scales, the model reasonably reproduces summer monsoon active and break phases, although with underestimated rainfall and surface wind signals. Its relatively high... |
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Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00349/46036/45703.pdf |
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