Meucci, Hugo (2016) Atmospheric blocking regimes and their relationship with extratropical atmospheric circulation characteristics PRE - Research Project, ENSTA.
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Abstract
Atmospheric blocking is related to a high pressure, large-scale system which stops the usual West-to-East atmospheric flow in mid-latitude (cf. IPCC, chapter 14, 2013). This atmospheric flow blocking causes several days of same weather and therefore climate anomalies on the affected regions. This study aims to assess blocking effects, through their teleconnexions, on the global ocean-atmosphere characteristics and on extratropical storms over North-Atlantic. Then, these effects are analysed on the particular case of the year 2010. To this end, the NCEP-DOE1 reanalysis have been used and blocking events are detected with the method described in the study of Barriopedro et al. (2005). The BWA2 index which characterises mid-tropospheric circulations is also computed in order to understand those links. It is shown that a positive BWA phase favors a blocking occurrence over Atlantic (all year) and over Eastern Pacific (in spring). Furthermore, the study has shown that blockings over the Atlantic Ocean are linked to the La Niña events and to a modification of extratropical storm tracks over Atlantic. In that case, Southern Europe is subject to more storminess than Northern Europe as usual. Finally, a link between an increasing number of storms that exceed 75°N, very important for the Arctic climate and sea-ice cover, and the atmospheric blocking over Europe has been shown.
Item Type: | Thesis (PRE - Research Project) |
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Uncontrolled Keywords: | Atmospheric blocking, teleconnexions, extratropical storms |
Subjects: | Earth Sciences and Environmental Engineering |
ID Code: | 6707 |
Deposited By: | Hugo Meucci |
Deposited On: | 06 sept. 2016 14:54 |
Dernière modification: | 06 sept. 2016 14:54 |
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