Scopus记录号: 2-s2.0-85046025553
论文题名: Northern Hemisphere extratropical winter cyclones variability over the 20th century derived from ERA-20C reanalysis
作者: Varino F. ; Arbogast P. ; Joly B. ; Riviere G. ; Fandeur M.-L. ; Bovy H. ; Granier J.-B.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2019
卷: 52, 期: 2019-01-02 起始页码: 1027
结束页码: 1048
语种: 英语
英文关键词: 20th century
; Arctic warming
; Climate change
; Cyclone tracking
; ERA-20C
; Storm track
英文摘要: The multi-decadal variations of wintertime extra-tropical cyclones during the last century are studied using a vorticity-based tracking algorithm applied to the long-term ERA-20C reanalysis from ECMWF. The variability of moderate-to-deep extra-tropical winter cyclones in ERA-20C show three distinct periods. Two at the beginning and at the end of the century (1900–1935 and 1980–2010) present weak or no significant trends in the Northern Hemisphere as a whole and only some regional trends. The period in between (1935–1980) is marked by a significant increase in Northern Hemisphere moderate-to-deep cyclones frequency. During the latter period, polar regions underwent a significant cooling over the whole troposphere that increased and shifted poleward the mid-latitude meridional temperature gradient and the baroclinicity. This is linked to positive-to-negative shifts of the PDO between 1935 and 1957 and of the AMO between 1957 and 1980 which mainly reinforced the storm-track eddy generation in the North Pacific and North Atlantic regions respectively, as seen from baroclinic conversion from mean to eddy potential energy. As a result, both the North Pacific and North Atlantic extra-tropical storms increase in frequency during the two subperiods (1935–1957 and 1957–1980), together with other storm-track quantities such as the high-frequency eddy kinetic energy. In contrast, the first and third periods are characterized by a warming of the polar temperatures. However, as the stronger warming is confined to the lower troposphere, the baroclinicity do not uniformly increase in the whole troposphere. This may explain why the recent rapid increase in polar temperatures has not affected the behaviour of extratropical cyclones very much. Finally, the large magnitude of the positive trend found in moderate-to-deep cyclone frequency during the second period is still questioned as the period is marked by an important increase in the number of assimilated observations. However, the dynamical link between changes in cyclone frequency, changes in large-scale baroclinicity and ocean decadal variability found in the present study makes us confident on the sign of the detected cyclone trend. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature. 资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/122427
Appears in Collections: 气候变化事实与影响
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作者单位: CNRM, UMR 3589, Météo-France/CNRS, Toulouse, France; CNRM, UMR 3589, Météo-France, Toulouse, France; LMD/IPSL, Département de Géosciences, ENS, PSL Research University, Ecole Polytechnique, Université Paris Saclay, Sorbonne Universités, UPMC Univ Paris 06, CNRS, Paris, France; SCOR, Paris, France
Recommended Citation:
Varino F.,Arbogast P.,Joly B.,et al. Northern Hemisphere extratropical winter cyclones variability over the 20th century derived from ERA-20C reanalysis[J]. Climate Dynamics,2019-01-01,52(2019-01-02)