Seasonality of Precipitation in TURKEY: Present and Future Assessments

Abstract

In this study, the non-parametric circular statistical method is used to analyze seasonality of precipitation over Turkey for past (1956-1975) and present (1986-2005) periods using both station data and gridded observation data (CRU-3.24). This method is also applied to the CORDEX Europe domain for three different periods which cover early century (2016-2035), mid-century (2046-2065) and end-century (2081-2099) to investigate the potential future changes in the seasonality under a pessimistic climate scenario, CMIP5-RCP 8.5 (Coupled Model Intercomparison Project phase 5-Representative Concentration Pathways 8.5).

Seasonality Index (SI) over Turkey decreases from south (~0.6) to north (~0.1) for past and present periods. For the future periods, SI tends to increase in the south, especially in the south-eastern Anatolian region, while it tends to decrease over the Black Sea and central Anatolian regions. Beside SI, another outcome from the circular statistics is the average occurrence time of precipitation during a year. Winter months (December-January-February) are common occurrence time of precipitation in general for past and present periods. Precipitation occurrence time for the future periods does not change much in the future periods for most of the regions except for the central Black Sea and southeastern Anatolia where it shifts to October and November, respectively.    

Keywords

• Precipitation,Seasonality,Circular Statistic,CMIP5-RCP8.5

Abstract

Keywords

• Yağış,Mevsimsellik,Dairesel İstatistik,CMIP5-RCP8.5

References

1. [1] Bozkurt D., Turuncoglu U., Sen O.L., Onol B., Dalfes H.N., 2012: Downscaled simulations of the ECHAM5, CCSM3 and HadCM3 global models for the eastern Mediterranean–Black Sea region: evaluation of the reference period, Clim Dyn., 39, pp. 207–225. [2] Bozkurt D., Sen O.L., Hagemann S., 2015: Projected river discharge in the Euphrates-Tigris Basin from a hydolojical discharge model forced with RCM and GCM outputs, Climate Research, 62, pp. 131–147, doi:10.3354/cr01268.
2. [3] Climatic Research Unit (CRU), University of East Anglia, 2017https://crudata.uea.ac.uk/cru/data/hrg/cru_ts_3.24.01/
3. [4] Demircan M., Gurkan H., Eskioglu O., Arabaci H., and Coskun M., 2017: Climate Change Projections for Turkey: Three Models and Two Scenarios, Turkish Journal of Water Science&Management, Vol.1.
4. [5] Dingman S. l., “Physical Hydrology”, Prentice Hall, New Jersey, USA, 2002, pages 143-145. [6] Evans J.P., Smith R.B. and Oglesby R. J., 2004: Middle East climate simulation and dominant precipitation processes, Int. J. Climatol., 24, pp.1671-1694. [7] Giorgi F., Lionello P., 2008: Climate change projections for the Mediterranean region, Global and Planetary Change, 63, pp. 90-104. [8] Gokmen M., 2016: Spatio-temporal trend in the hydroclimate of Turkey for the last decades based on two reanalysis datasets, Hydrol.Earth Syst. Sci., 20, pp. 3777-3788. [9] Hertig E. and Jacobeit J., 2008: Assessment of Mediterranean precipitation changes for the 21st century using statistical downscaling techniques, Int. J. Climatol., 28, pp. 1025-1045. [10] IPCC: Climate Change 2007: Impacts, Adaptation, and Vulnerability, edited by: Parry, M. L., Canziani, O. F., Palutikof, J. P., van der Linden, P. J., and Hanson, C. E., Cambridge University Press, Cambridge, UK, pp. 976, 2007. https://www.ipcc.ch/publications_and_data/ar4/wg2/en/contents.html [11] IPCC: Climate Change 2014: Synthesis Report, Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Core Writing Team, Pachauri, R. K., and Meyer, L. A., IPCC, Geneva, Switzerland, pp. 151, 2014. https://www.ipcc.ch/report/ar5/syr/ [12] Kadioglu M., 2000: Regional variability of seasonal precipitation over Turkey, Int. J. Climatol., 20, pp. 1743-1760. [13] Krichak, S. O., Alpert, P., Bassat, K., and Kunin, P., 2007: The surface climatology of the eastern Mediterranean region obtained in a three-member ensemble climate change simulation experiment, Adv. Geosci., 12, pp. 67-80.
5. [14] Mariotti A., Zeng N., Yoon J.-H., Artale V., Navarra A., Alpert P., and Li L. Z.X., 2008: Mediterranean water cycle changes: transition to drier 21st century conditions in observations and CMIP3 simulations, Environ. Res. Lett., 3, doi:10.1088/17489326/3/4/044001.
6. [15] Markham C.G., 1970: Seasonality of precipitation in the United States. Annals of the Association of American Geographers, 60, pp. 593-597.
7. [16] Onol B. and Semazzi F.H.M., 2009: Regionalization of climate change simulations over Eastern Mediterranean. J Clim., 22, pp.1944–1961. doi:10.1175/2008JCL11807.1. [17] Onol B., Bozkurt D., Turuncoglu U.U., Sen O.L., Dalfes H.N., 2014: Evaluation of the twenty-first century RCM simulations driven by multiple GCMs over the Eastern Mediterranean–Black Sea region, Clim Dyn, 42, pp. 1949-1965. [18] Partal T. and Kahya E., 2006: Trend analysis in Turkish precipitation data, Hydrol. Process., 20, pp. 2011-2016. [19] Turkes M., 1996: Spatial and temporal analysis of annual rainfall variations in Turkey, Int. J. Climatol, 16, pp. 1057-1076. [20] Turkes M., Koc T., and Saris F., 2009: Spatiotemporal variability of precipitation total series over Turkey, Int. J. Climatol., 29, pp. 1056-1074.