Advances in Geosciences www.adv-geosci.net 1680-7340 1680-7359 25 Precipitation: Measurement, Climatology, Remote Sensing, and Modeling (EGU Session 2009) 2010 10.5194/adgeo-25-161-2010 http://www.adv-geosci.net/25/161/2010/ http://www.adv-geosci.net/25/161/2010/adgeo-25-161-2010.html http://www.adv-geosci.net/25/161/2010/adgeo-25-161-2010.pdf 161 166 2010-06-15 On the relationship of orography with extreme dry spells in Greece C. Oikonomou H. A. Flocas efloca@phys.uoa.gr G. Katavoutas M. Hatzaki D. N. Asimakopoulos C. Zerefos Department of Environmental Physics and Meteorology, Faculty of Physics, University of Athens, Greece Department of Climatology and Atmospheric Environment, Faculty of Geology and Geoenvironment, University of Athens, University of Athens, Greece The objective of this study is to investigate the relationship of orography over Greece with prolonged dry spells, as represented by the maximum number consecutive dry days (CDD index) during an extremely dry summer. For this purpose a simulation experiment was conducted with the aid of the regional climate model RegCM3.1 using a spatial resolution of 10 km. It was shown that a significant precipitation regime formed over the mountainous areas of continental Greece and Crete during this dry summer, due to orographically forced precipitation, consequently influencing the length of dry spells. Furthermore, the CDD appears spatial variations over the maritime areas, despite the zero or insignificant precipitation. The sensitivity test that was performed with the elimination of orography demonstrated the important role that orography plays in the distribution of CDD, since significant lengthening of extreme dry spells was found over the mountainous areas. Alpert, P., Krichak, S. O., Shafir, H., Haim, D., and Osetinsky, I.: Climatic trends to extremes employing regional modelling and statistical interpretation over the E. Mediterranean, Global Planet Change, 63, 163–170, 2008. Anagnostopoulou, C., Maheras, P., Karacostas, T., and Vafiadis, M.: Spatial and temporal analysis of dry spells in Greece, Theor. Appl. Climatol., 74, 77–91, 2003. Arseni-Papadimitriou, A., Maheras, P., and Giles, B.: Contribution to the study of the strong north winds on Aegean Sea in warm season, Rivista di Meteorologia Aeronautica 48(3–4), 131–137, 1988. Bartzokas, A., Lolis, C. J., and Metaxas, D. A.: A study on the intra-annual variation and the spatial distribution of precipitation amount and duration over Greece on a 10-day basis, Int. J. Climatol., 23, 207–222, 2003. Bergant, K., Belda, M., and Halenka, T.: Systematic errors in the simulation of European climate (1961–2000) with RegCM3 driven by NCEP/NCAR reanalysis, Int. J. Climatol., 27(4), 455–472, 2007. Dimri, A. P. and Ganju, A.: Wintertime Seasonal Scale Simulation over Western Himalaya Using RegCM3, Pure. Appl. Geophys., 164, 1733–1746, 2007. Fotiadi, A. K., Metaxas, D. A., and Bartzokas, A.: A statistical study of precipitation in NW Greece, Int. J. Climatol., 19, 1221–1232, 1999. Giorgi, F., Pal, J. S., Bi, X., Sloan, L., Elguindi, N., and Solmon, F.: Introduction to the TAC special issue: the RegCNET network, Theor. Appl. Climatol., 86, 1–4, 2006. Hatzaki, M., Flocas, H. A., Giannakopoulos, C., and Maheras, P.: The impact of Eastern Mediterranean Teleconnection Pattern on eastern Mediterranean climate, J. Climate., 22, 977–992, 2009. Hatzianastasiou, N., Katsoulis, B., Pnevmatikos, J., and Antakis, V.: Spatial and temporal variation of precipitation in Greece and surrounding regions based on global precipitation climatology project data, J. Climate., 21, 1349–1370, 2008. Houssos, E. E., Lolis, C. J., and Bartzokas, A.: Atmospheric circulation patterns associated with extreme precipitation amounts in Greece, Adv. Geosci., 17, 5–11, 2008. Kotroni,V., Lagouvardos, K., Kallos, G., and Ziakopoulos, D.: Severe flooding over central and southern Greece associated with pre-cold frontal orographic lifting, Q. J. Roy. Meteor. Soc., 125, 967–991, 1999. Kotroni, V., Lagouvardos K, and Lalas D.: The effect of the island of Crete on the etesian winds over the Aegean Sea, Q. J. Roy. Meteor. Soc., 127, 1917–1937, 2001. Lolis, C. J., Bartzokas A., and Metaxas, D. A.: Spatial covariability of the climatic parameters in the Greek area, Int. J. Climatol., 19, 185–196, 1999. Maheras, P. and Anagnostopoulou, C.: Circulation Types and their Influence on the interannual variability and precipitation changes in Greece, Mediterranean Climate-Variability and Trends, Springer Verlag, Berlin, Heidelberg, 215–239, 2003. Maheras, P., Tolika, K., Anagnostopolou, C., Vafiadis, M., Patrikas, I., and Flocas, H. A.: On the relationships between circulation types and changes in rainfall variability in Greece, Int. J. Climatol., 24, 1695–1712, 2004. Metaxas, D. A.: Evidence on the importance of diabatic heating as divergence factor in the Mediterranean, Arch. Meteor. Geophy. A., 27A, 69–80, 1978. Metaxas, D. A. and Bartzokas, A.: Pressure covariability over the Atlantic, Europe and N. Africa. Application: centers of action for temperature, winter precipitation and summer winds in Athens, Greece, Theor. Appl. Climatol., 49, 9–18, 1994. Oikonomou, C., Flocas, H., Hatzaki, M., Nisantzi, A., and Asimakopoulos D. N: Relationship of extreme dry spells in Eastern Mediterranean with large scale circulation, Theor. Appl. Climatol., 100, 137–151, 2010. Pal., J. S., Giorgi, F., Bi, X., Elguindi, N., Solmon, F., Gao, X., Rauscher, S. A., Francisco, R., Zakey, A., Winter, J., Ashfaq, M., Syed, F. S, Bell, J., Diffenbaugh, N., Karmacharya, J., Konare, A., Martinez, D., da Rocha, R., Sloan, L. C., and Steiner, A.: Regional climate modeling for the developing world:the ICTP RegCM3 and RegCNET, B. Am. Meteorol. Soc., 88, 1395–1409, 2007. Repapis, C. C., Zerefos, C., and Tritakis, B.: On the etesians over the Aegean, Proc. Acad. Athens, 572–606, 1978. Rodwell, M. J. and Hoskins, B. J.: Monsoons and the dynamics of the deserts, Q. J. Roy. Meteor. Soc., 122, 1385–1404, 1996. Roe, G. H.: Orographic precipitation, Annu. Rev. Earth Pl. Sc., 33, 645–671, 2005. Schmidli, J., Frei, C., and Widale P. L.: Downscaling from GCM precipitation: a benchmark for dynamical and statistical downscaling methods, Int. J. Climatol., 26, 679–689, 2006. Sioutas, M. and Flocas, H. A.: Hailstorms in Northern Greece: synoptic patterns and thermodynamic environment, Theor. Appl. Climatol., 75, 189–202, 2003. Spanos, S., Maheras, P., Karacostas, T., and Pennas, P.: Objective climatology of 500hPa cyclones in central and east Mediterranean region during warm-dry period of the year, Theor. Appl. Climatol., 75, 167–178, 2003. Tolika, K., Maheras, P., Vafiadis, M., Flocas, H. A., and Arseni-Papadimitriou, A.: Simulation of seasonal precipitation and raindays over Greece: a statistical downscaling technique based on artificial neural networks (ANNs), Int. J. Climatol., 27, 61–881, 2007. Xoplaki, E., Luterbacher, J., Burkard, R., Patrikas, I., and Maheras, P.: Connection between the large-scale 500hPa geopotential height fields and precipitation over Greece during wintertime, Clim. Res., 14(2), 129–146, 2000. Zanis, P., Douvis, K., Kapsomenakis, I., Kioutsioukis, I., Melas, D., and Pal, J. S.: A sensitivity study of the Regional Climate Model (RegCM3) to the convective scheme with emphasis in central eastern and southeastern Europe, Theor Appl. Climatol., 97, 327–337, 2009a. Zanis, P., Kapsomenakis, I., Philandras, C., Douvis, K., Nikolakis, D., Kanellopoulou, E., Zerefos, C., and Repapis, C.: Analysis of an ensemble of present day and future regional climate simulations for Greece, Int. J. Climatol., 29, 1614–1633, 2009b.