Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Drought Assessment in Aydın and İzmir Districts in Turkey(01. Izmir Institute of Technology, 2022) Mersin, Denizhan; Safari, Mir Jafar Sadegh; Tayfur, GökmenDrought indices are widely used in order to track the severity, duration, and frequency of droughts, drought indices are frequently utilized. Turkey's Aegean region, which is expanding, has a range of water resources, including lakes, streams, lakes, and groundwater aquifers. In this study, the drought features in the Büyük Menderes, Küçük Menderes, and Gediz basins in the Aegean area of Turkey are investigated using long-term total precipitation and temperature records from 14 meteorological stations between 1973 and 2020 (47 years). For this, the Standardized Precipitation Index (SPI) and the Standardized Precipitation and Evapotranspiration Index (SPEI), and Discrepancy Precipitation Index (DPI) are used to investigate drought patterns, monthly and over 3-, 6-, and 12-month (annual) periods. The results reveal that the monthly indices show almost the same results for the whole study area, but the different indices differ in the severity of drought. As a common belief, moderate, severe, and extreme drought is observed at the end of the 1980s and around 2020, which is the closest year to the present. In addition, the trend analysis of the annual temperature (daily average) and total precipitation time series data collected from these 14 stations is examined. Sen test, Mann-Kendall test, and Spearman's rho test are used for trend detection. The Pettitt test is used to estimate the magnitude of the slope in the series and the Theil-Sen approach is used to detect the change point of the series. For precipitation, all stations showed a statistically significant increase in trends. In the temperature analysis, on the other hand, all stations show statistically significant increasing trends in daily average temperatures. The amount of precipitation increase determined by the Theil-Sen test is found to be between 4.2 and 7.9 mm/year.Master Thesis Trend and Drought Analysis of Three Stations in the Puntland State of Somalia(Izmir Institute of Technology, 2022) Muse, Nur Mohamed; Tayfur, GökmenLong-term rainfall and temperature records were used to analyze drought features as well as temperature and precipitation trends in Somalia's north area from 1980 to 2020. Monthly records are being used at three locations (Bossaso (station 1), Qardho (station 2), and Garowe (station 3).Deciles, Discrepancy precipitation index, percent normal, Gamma, log normal, and normal-SPI were used to examine the Drought. The past extreme and severe droughts that occurred in the early 1980s and throughout the course of the last two decades are being detected using the log-SPI, gamma-SPI, PN, and Deciles The Mann Kendall (MK) test, Spearman's rho (SR test), and the Şen trend test were used in the trend analysis to identify trends in time series, and the Pettitt test to detect change points in time series. In contrast, the Thiel-sen Approach was used to estimate the magnitude of the slope in the precipitation and temperature time series. The average temperature and annual precipitation are increasing by about 0.3C per decade and 3 mm per year, according to the trend analysis results.Master Thesis Drought and Trend Analysis in Trarza Region Im Mauritania(Izmir Institute of Technology, 2016) Traore, Ely Yacoub; Tayfur, GökmenLong-term precipitation and temperature historical records (monthly recorded for 44 years) in three stations (Boutilimit (station 1), Nouakchott (station 2), and Rosso (station 3)) are employed to investigate the drought characteristics and to investigate the temperature and precipitation trends during the period of 1970 to 2013 in Trarza region in Mauritania. Six Drought Indices (DIs), namely normal Standardized Precipitation Index (normal-SPI), log normal Standardized Precipitation Index (log-SPI), Standardized Precipitation Index using Gamma distribution (Gamma-SPI), Percent of Normal (PN), the China-Z index (CZI), and Deciles are used for the drought analysis. These methods are based on 1-, 3-, 6-, and 12 month time periods. The results showed that the log-SPI, the gamma-SPI, PN and Deciles were able to capture the historical extreme and severe droughts observed in early 1970s and early 1980s. In the trend analysis, The Mann Kendall (MK test), Spearman’s rho (SR test), Şen trend test were used for the trend identification in the time series and the Pettitt test for detecting the change point at the time series while the Thiel-sen Approach was used to estimate the magnitude of the slope in the precipitation and temperature time series. The results of trend analysis showed that the average temperature and the annual precipitation are both increasing by about 0.3oC per decade and 3 mm per year, respectively.