JaLCDOI 10.18926/ESR/55324
Sort Key 6
Title Alternative A case study on the cyclone activity around Europe from winter to spring of 2000
FullText URL esr_023_1_033_042.pdf
Author Kuwana, Yusuke| Kato, Kuranoshin| Takigawa, Yumi| Kojima, Yumi| Otani, Kazuo|
Abstract Although the extratropical cyclone is one of the basic systems that characterize the weather and climate in mid-latitude regions with the large meridional temperature gradient, its activity and characteristics would be greatly influenced by the seasonal transition and regional differences of the mean atmospheric fields such as between Europe and East Asia. Furthermore, detailed knowledge of the daily cyclone activity would help to understand deeply the differences of regional climatology including seasonal cycles among various areas. In such interest, the present study performed a case study on the cyclone activity around Europe from winter to spring of 2000. In winter, intraseasonal variation of the Icelandic Low was dominant. In the stage when such intraseasonal-scale Icelandic Low approached to the northwestern Europe, the several lows passed eastward with a few days interval around the intraseasonal-scale low pressure area or its southern edge where the baroclinicity was relatively strong. It is also noted that their center pressure was rather low (below 980hPa). After April, when the seasonal mean Icelandic low had disappeared, different types of the intra-seasonal-scale cyclones and anticyclones were dominantly observed. In the lower SLP stage of the intraseasonal variation in Europe, the low to the southwest of England in the middle of April was of the equivalent barotropic structure and persisted for about ten days. On the other hand, high pressure area extending from England to the northern coast of Germany also persisted for about half month. The southern half of that high area was also of equivalent barotropic structure with warmer air there.
Keywords cyclone activity around Europe comparative climatology between Europe and East Asia seasonal cycle dynamic climatology
Publication Title Okayama University Earth Science Report
Published Date 2016-12-27
Volume volume23
Issue issue1
Publisher 岡山大学理学部地球科学教室
Publisher Alternative Department of Earth Sciences, Faculty of Science, Okayama University
Start Page 33
End Page 42
ISSN 1340-7414
NCID AN10506284
Content Type Departmental Bulletin Paper
language 日本語
Copyright Holders © 2016 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved
File Version publisher
Refereed False
Eprints Journal Name esr
JaLCDOI 10.18926/ESR/53195
Sort Key 6
Title Alternative A preliminary study on the seasonal cycles of the cyclone activity and the large-scale fields in Europe at the viewpoint comparing with those in East Asia
FullText URL esr_021_1_023_032.pdf
Author Takigawa, Yumi| Haga, Yuichi| Matsumoto, Kengo| Kato, Kuranoshin|
Abstract  Preliminary analyses on the seasonal cycles of the large-scale atmospheric mean fields and the cyclone activity in Europe were performed based mainly on the NCEP/NCAR re-analysis data, at the viewpoint comparing with those in East Asia.  As for the climatological monthly mean fields (1981~2010), the meridional temperature gradient in East Asia presents striking seasonal change with the maximum in winter and the minimum in summer. It is interesting that such transition from winter to summer and that from summer to winter occur rather rapidly accompanied by the great temperature increase around April to June and the decrease around October to November, respectively, in a wide region of 40~70N. On the other hand, the temperature gradient in Europe is significantly smaller with slight seasonal change than that in East Asian winter.  By the way, in spite of the above difference of the horizontal temperature gradient between Europe and East Asia, the cyclone activity does not seem to be so weak even around Europe. Thus, the seasonal cycles of the characteristics of the cyclones and their environmental fields around Europe were examined. At the first step, we analyzed the daily cyclone activity in Europe for January and July of 2000. Many low pressure centers at the surface level appeared in both January and July. Referring also to the daily maps of sea level pressure and geopotential height at 500 hPa level, we found that not only the cyclones corresponding to the baroclinic instability waves, but also to the cold vortices which amplitudes increased with height appeared frequently. Moreover, it is interesting that the large-scale cold vortex, which embeds the shortwave trough with the low center at the surface level, appeared in the northern Europe in July as in East Asian winter, when such multi-scale systems sometimes bring the persisting heavy snowfall events in the Japan Sea side of the Japan Islands.
Keywords seasonal cycle cyclone activity Europe and East Asia
Publication Title Okayama University Earth Science Report
Published Date 2014-12-27
Volume volume21
Issue issue1
Publisher 岡山大学理学部地球科学教室
Publisher Alternative Department of Earth Sciences, Faculty of Science, Okayama University
Start Page 23
End Page 32
ISSN 1340-7414
NCID AN10506284
Content Type Departmental Bulletin Paper
language 日本語
Copyright Holders © 2014 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved
File Version publisher
Refereed False
NAID 120005567874
Eprints Journal Name esr