Advertisement

Atmospheric Circulation Characteristics Associated with high Static Instability Conditions Over the Athens Region

  • E. Serbis
  • C. J. Lolis
  • P. A. Kassomenos
Conference paper
Part of the Springer Atmospheric Sciences book series (SPRINGERATMO)

Abstract

The main atmospheric circulation characteristics associated with high static instability conditions over the Athens region are examined for the period 1974–2004. The data used consist of daily (12UTC) values of: (1) 850, 700 and 500 hPa air temperature and dew point from radiosonde measurements at the Athens Hellinikon airport (BADC) and (2) 2.5 × 2.5 grid point 500 and 1,000 hPa geopotential height over the Mediterranean region (NCEP/NCAR), for the period 1974–2004. The stability index K (K-index) is calculated from the radiosonde measurements. Then, 5 % of the days (280 days) with the highest K values (highest instability days) are selected for the cold (16/10–15/4) and the warm (16/4–15/10) period of the year. For these days, a classification is applied to the geopotential height spatial distributions, by using Factor Analysis and K-means Cluster Analysis. The selected days are classified into nine clusters for the cold period and five clusters for the warm period. The mean 500 and 1,000 hPa geopotential height patterns are constructed for the days classified into each one of the clusters. According to the results, the clusters correspond to distinct circulation types associated with high instability conditions over the Athens region.

Keywords

Geopotential Height Warm Period Cold Period Atmospheric Stability Middle Troposphere 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

References

  1. Andersson T, Andersson M, Jacobsson C, Nilsson S (1989) Thermodynamic indices for forecasting thunderstorms in southern Sweden. Meteorol Mag 118:141–146Google Scholar
  2. Dalezios NR, Papamanolis NK (1991) Objective assessment of instability indices for operational hail forecasting in Greece. Meteorol Atmos Phys 45(1–2):87–100. doi: 10.1007/BF01027477 CrossRefGoogle Scholar
  3. Jacovides CP, Yonetani T (1990) An evaluation of stability indices for thunderstorm prediction in greater Cyprus. Weather Forecast 5:559–569CrossRefGoogle Scholar
  4. Jolliffe IT (1986) Principal component analysis. Springer, New YorkGoogle Scholar
  5. Kalkstein LS, Nichols MC, Barthel CD, Greene JS (1996) A new spatial synoptic classification: application to air mass analysis. Int J Climatol 16:983–1004CrossRefGoogle Scholar
  6. Kalnay E, Kanamitsu M, Kistler R, Collins W, Deaven D, Gandin L, Iredell M, Saha S, White G, Woollen J, Zhu Y, Leetmaa A, Reynolds B, Chelliah M, Ebisuzaki W, Higgins W, Janowiak J, Mo KC, Ropelewski C, Wang J, Jenne R, Joseph D (1996) The NCEP/NCAR 40-year reanalysis project. B Am Meteorol Soc 77:437–471. doi:10.1175/1520-0477(1996) 077<0437:TNYRP>2.0.CO;2CrossRefGoogle Scholar
  7. Karacostas TS, Kakaliagou OK, Flocas EA (1991) An objective evaluation of two instability indices associated with forecasting convective storms over the north and central Greece. Geofiz 8:51–59Google Scholar
  8. Kassomenos PA, Sindosi OA, Lolis CJ (2003) Seasonal variation of the circulation types occurring over southern Greece: a 50-year study. Clim Res 24:33–46. doi: 10.3354/cr024033 CrossRefGoogle Scholar
  9. Kistler R, Kalnay E, Collins W, Saha S, White G, Woollen J, Chelliah M, Ebisuzaki W, Kanamitsu M, Kousky V, van den Dool H, Jenne R, Fiorino M (2001) The NCEP/NCAR 50-year reanalysis: monthly means CD-ROM and documentation. B Am Meteorol Soc 82:247–267CrossRefGoogle Scholar
  10. Lolis CJ (2007) Climatic features of atmospheric stability in the Mediterranean region (1948–2006): spatial modes, inter-monthly, and inter-annual variability. Meteorol Appl 14:361–379. doi: 10.1002/met.36 CrossRefGoogle Scholar
  11. Marinaki A, Spiliotopoulos M, Michalopoulou H (2006) Evaluation of atmospheric instability indices in Greece. European Geosciences Union. Adv Geosci 7:131–135CrossRefGoogle Scholar
  12. Richman MB (1986) Rotation of principal components. J Climatol 6:293–335CrossRefGoogle Scholar
  13. Sharma S (1995) Applied multivariate techniques. Wiley, New YorkGoogle Scholar
  14. Showalter AK (1953) A stability index for thunderstorm forecasting. B Am Meteorol Soc 34:250–252Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  1. 1.Laboratory of Meteorology, Department of PhysicsUniversity of IoanninaIoanninaGreece

Personalised recommendations