AYBE- İklim ve Deniz Bilimleri Lisansüstü Programı - Yüksek Lisans
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ÖgeTürkiye'de İklim Uç Olayları İndislerinin Tarihsel Değişimi(Eurasia Institute of Earth Sciences, 2015-01-20) Dündar, Berna ; Şen, Ömer Lütfi ; 601111003 ; Climate and Marine Sciences ; İklim ve Deniz Bilimleri Anabilim DalıThe climate system has a profound effect on life on the Earth. People's daily life mainly depends on weather that surrounds them. Besides, wheather and climate extremes have significant influence on society, environment and the economy. Hence, it is very important to study them. ETCCDI defined 27 core indices for investigating extreme events. In this study 14 indices from them has been analysed. Daily temperature and precipitation data for 452 stations, obtained from Turkish State Metereological Service. In order to eliminate stations with missing values, data visualization method used and 134 stations selected from 452 stations. These data were used for trend analysis of these indices between the periods 1965 – 2006. The Sequentiall Mann Kendall non-parametric test applied for trend analysis of the indices. This version of the Mann Kendall test used to determine the beginning of a trend within a sample. Firstly, in this study annual maximum and minimum temperature trends examined for four months that were October, May, January and July. In addition, their annual precipitation investigation have been done. According to this examination, annual maximum temperatures of July', October and May showed increasing trends whereas there was not any spatially coherent trend observed for January. Annual minimum temperature investigation revealed that for July' there was spatially coherent increasing trend throughout the country. In contrast, just one station indicated decreasing trend that was Erzurum. Moreover, the same behavior observed for October' annual minimum temperatures also. Annual minimum temperatures for May' indicate both increasing and decreasing trends for some stations. There was not any annual precipitation pattern found for these months. Secondly, trend analysis of 14 indices studied. According to this analysis, there was no spatially coherent increasing or decreasing trend for "number of frost days", though the few stations that indicate increasing behaviour were mainly in the northern half of the country. On the other hand, "numbers of summer days" have been increasing in Turkey; and the significant increases distributed throughout the country with the exception of Southeastern Anatolia region. For "tropical nights", stations located around the Marmara Sea, Mediterranean coastal areas and northeast of the country showed increasing trends. There weren't any trends observed for "growing season length" and "icing days". Trend analysis of monthly maximum temperatures of daily maximum and minimum, monthly minimum temperatures of daily maximum and minimum have been done for January and July. No trends observed for January. However, there was an increasing trend for monthly maximum value of daily minimum temperatures of July. This trend observed along coastal areas, especially Aegean and Mediterranean regions and some stations around Marmara Sea. Furthermore, a few stations on the Black Sea coastline and some inland stations showed this behavior also. Trend analysis of monthly minimum value of daily maximum temperature of July indicated an increasing trend along the Mediterranean and Aegean coastlines. Besides, the same behavior observed at some stations located in the Southeast, Central Anatolia and northeast of the Black Sea Region. Trend analysis of monthly minimum value of daily minimum temperature of July showed an increasing trend along the Mediterranean, Aegean coastlines and some stations around Marmara Sea. Moreover, some stations in the west, central and northern part of the country. Trend analyses of daily temperature range done for January and July. For January, there wasn't any spatially coherent trends observed; some stations showed decreasing; some Aegean coastline and inland stations indicated increasing trend. Trend analyses of July showed that stations mainly in the northern part of the country indicated increasing trend wheras some stations located in the Mediterraean coastal areas and southeast and east part of the country showed decreasing behavior. Trend analyses of precipitation indices were done as well. However, there wasn't any trend observed for monthly maximum 1-day precipitation, also monthly maximum consecutive 5-day precipitation. Moreover, no trend observed for R10mm (annual count of days when precipitation ≥ 10 mm) and R20mm. In this study, 134 stations annual maximum and minimum temperature and precipitation data have been analysed for the period 1965-2006. In addition, 14 climate extreme indices trends have been investigated for the same period. Consequences from this research revealed that; annual maximum temperature of July, October and May indicated increasing trends. Besides, annual minimum temperature of July and October showed increasing tendency throughout the country. However, there wasn't any precipitation pattern found for Turkey. In addition, increasing trend observed for number of summer days and tropical nights whereas there weren't any spatially coherent trends observed for growing season length and icing days. Monthly maximum and minimum temperatures displayed increasing trend for July. However, no trends observed for January. Hence, it may infer that the effect of climate change on Turkey is more obvious in the warmer part of the year.