Esra AYDINÃ–Z 1, Remziye YILDIZ GÃśLAĞACI2, HÃŒseyin Sefa HIZLI 2, Feride ALTINGÃ–Z 2
1, General Directorate of State Hydraulic Works GAP 15th Regional Directorate2
Climate change in any region occurs by various factors. Global warming, water structures, irrigation projects, afforestation and urbanization takes part in these factors. Climate change in GAP region is connected with dams in this area, large irrigation fields and urbanization based on GAP projects besides global scale changes. Geographical effect in the region of Atatürk Dam which is the biggest dams in the world together with large irrigation projects should not be underestimated. Level values of Atatürk Dam Lake have reached 850 km2 lake areas fastening its level about 530 meters in 1994 from 1989 with a constant rise. The total field with Şanlıurfa irrigations is approximately 2 070 km2 . It can be analysed with homogeneity test whether average of observation series change. Deterioration of the homogeneity of the observation series again depends on change of environmental and climatic factors with time. The construction of a dam and transformation from dry farming to irrigated farming especially for large fields come up as main factors which deteriorate homogeneity. In this study, data sets as monthly mean temperature, monthly maximum temperature, monthly minimum temperature, monthly mean relative humidity and monthly total precipitation observations between 1970-2014 acquired from Şanlıurfa, Siverek, Hilvan, AkÃ§akale, Ceylanpınar and Bozova meteorological stations connected to General Directorate of Meteorology will be used. In the result of observations depending on time, decrease or increase in observation averages will be defined as trend. As trends can occur for a specific time, it can also happen for long term due to dams as large water bodies, changes in land use or climatic changes. Component of trend in observations are analysed with nonparametric tests such as Kendall Rank Correlation Test and Spearman Rank Correlation Test. Significance of component of trend will be analysed by Kendall Rank Correlation Test in this study. Kendall Rank Correlation test was analyzed with the observations change over time and showed some tendency to increase or decrease in the seasons of observations. Then, before-after observations of dam and, before-after observations of irrigation results analyzed by Mann-Whitney test change were obtained. Change in the average of before-after dam and before-after irrigation observation series will be analyzed by the nonparametric Mann-Whitney Test with separation of series in two subgroups. Therefore, first, data will be separated into four groups based on seasonal as winter, spring, summer and autumn. After that, it will be analysed whether there is any trend in seasonal data in order to examine possible climate changes in before-after dam and before-after irrigation. When examining some parameters which has significant in statistical tests can be addressed at following. When it is looked generally for Mann Kendall Rank Correlation Test for seasonal mean temperature; while it can be seen an increase in all stations in summer months, only in Şanlıurfa, there is an increase in spring time. According to Mann Whitney Tests based on before-after dam there is only difference in summer months but results for before-after irrigation show differences in spring, summer and autumn months. This situation shows that there is another reasons lead to increase mean temperatures in addition that global warming and urbanization. As it is looked for Mann Kendall Rank Correlation Test for seasonal mean relative humidity, an increase can be seen almost in all stations but there is a decrease for Ceylanpınar in all seasons. According to Mann Whitney Test based on before-after irrigation there is differentiation for all seasons in Bozova. Increases almost in all seasons in Siverek can be said because of dam effect with Mann Whitney Test results. Reason of increase in relative humidity in Bozova and Siverek can be thought due to being near Atatürk Dam.