Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2021Forecasting instantaneous sea level changes with machine learning methods in Aegean Sea
Kayıkçı, Emine Tanır; Yavuzdoğan, Ahmet
Forecasting instantaneous sea-level is of great importance in terms of determination of geodetic vertical datum and updating, conservation of coastal areas, monitoring coastal ecosystems, maintenance, and planning of coastal structures, monitoring of climate change effects. Traditional methods used for instantaneous sea level estimation are often based on linear assumptions. However, contributors to sea levels are very various and their effects vary from region to region. Generally, they have complex and nonlinear dependence structures. Therefore, nonlinear sea-level cannot be determined with high precision using linear models. Recently, machine learning prediction methods have been frequently used in the modelling of complex dependency structures between variables. Within the scope of this study, to predict the instantaneous sea level with high accuracy and to compare linear estimation methods with nonlinear estimation methods, the Multiple Linear Regression (MLR) linear model, Support Vector Regression (SVR) non-linear model, and Random Forest Regression (RFR) non-linear model algorithms were used, and their prediction performances were compared. As a result of the study, the highest prediction performance for instantaneous sea level was obtained with RFR, and the lowest prediction performance was obtained with the MLR method. As a result, it has been shown that instantaneous sea level can be predicted with high precision using RFR with the features used in this study, and the linear prediction models are insufficient in modelling the complex dependency structure of instantaneous sea level.
- MakaleAçık Erişim2020Ege Denizi Bağıl Deniz Seviyesi Değişimlerinde Kapula Fonksiyonları İle Trend Analizleri
Kayıkçı, Emine Tanır; Yavuzdoğan, Ahmet
İklim değişikliği başta olmak üzere birçok nedenden dolayı global ölçekte deniz seviyesinde meydana gelen artışlar, kıyı ekosistemlerinietkilemekte ve kıyı yerleşimlerini tehdit etmektedir. Jeodezik açıdan uzun dönemli deniz seviyesi gözlemleri düşey kontrol ağlarınındatumunun belirlenmesi açısından önemlidir. İstatistik, ekonomi, aktüerya analizi, meteoroloji, hidroloji gibi birçok alanda farklıdeğişkenler arasındaki ilişkileri araştırmak için kullanılan Kapula fonksiyonları değişkenlerin ve hatalarının dağılımındanetkilenmeyen, lineer ve lineer olmayan ilişkileri yansıtan, lokal bağımlılıkları da gösterebilen korelasyon yapısıyla lineer korelasyonkatsayısına göre oldukça elverişli bir korelasyon yapısı sunabilmektedir. Bu çalışmada, Ege Denizi kıyısında bulunan 5 mareografistasyonundan elde edilen 1990-2008 yılları arasında aylık deniz seviyesi ve deniz yüzey sıcaklığı ortalamaları verileri ile kıyılardakiuzun dönemli bağıl deniz seviyesi değişimleri ve bu değişimlerin deniz yüzey sıcaklığı ile ilişkisi Kapula Fonksiyonları ile incelenmiştir.Bu çalışma kapsamında ilk defa sunulan kapula temelli trend analiz yöntemi ile deniz seviyesi ve deniz yüzey sıcaklığı zaman serilerindetrend analizleri gerçekleştirilerek elde edilen trendler regresyon modelleri ile karşılaştırılmıştır. Ege denizinde 1990-1998 yıllarıarasında deniz seviyesinin oldukça hızlı bir şekilde arttığı, 1999-2008 yılları arasında ise deniz seviyesinin düştüğü görülmüştür. 1990-1998 yılları arasında deniz seviyelerindeki artışın deniz yüzey sıcaklıklarındaki sıcaklık artışlarından kaynaklandığı, 1999-2008 yıllarıarasındaki deniz seviyesindeki azalmaların da deniz yüzey sıcaklıklarındaki soğumalardan kaynaklandığı değerlendirilmiştir.
- MakaleYalnız künye2020Analysis of ionospheric TEC anomalies for global earthquakes during 2000-2019 with respect to earthquake magnitude (Mw≥6.0)
Ulukavak, Mustafa; Yalçınkaya, Mualla; Kayıkçı, Emine Tanır; Öztürk, Serkan; Kandemir, Raif; Karslı, Hakan
In this work, a relationship between ionospheric TEC anomalies and different earthquake magnitude groups before the main shocks was investigated. For this purpose, 2942 global earthquakes with Mw≥6 from 2000 to 2019 and possible ionospheric TEC anomalies that occurred before earthquakes were examined by considering 13 different index values of space weather conditions (geomagnetic storm indices and solar activity indices). Anomalies of ionospheric TEC changes were defined for 15-days before and 4-days after the earthquakes by using 15-days moving median method with the length of 15 days. Earthquakes were first grouped according to their magnitudes, and then negative and positive TEC anomalies in quiet days before the earthquakes were detected. These anomalies were observed as ∼5–13, ∼5-10, ∼5-15, ∼3-13, ∼7-15, ∼1 and ∼5-8 days ago for the earthquakes of 6.0 ≤ Mw<6.5, 6.5 ≤ Mw<7.0, 7.0 ≤ Mw<7.5, 7.5 ≤ Mw<8.0, 8.0 ≤ Mw<8.5, 8.5 ≤ Mw<9.0, and 9.0 ≤ Mw<9.5, respectively. Mean of changes in TEC anomalies of these groups is 44.2 % TECU and we detected that the number of positive anomalies in each group is larger than the number of negative anomalies. Consequently, these analyses clearly show that the day-to-day changes in TEC anomalies may supply significant precursors prior to the global earthquakes (M ≥ 6) in the short-term earthquake prediction for main shocks.
- MakaleYalnız künye2016Interpolation Method Used To Determine The Height Of Geoid, Application Of The Trabzon City Data, Turkey
Karaaslan, Özge; Kayıkçı, Emine Tanır; Aşık, Yusuf
Finding the spatial extent of known height used in engineering works quite time-consuming process that requires a difficult and cost. But the less time it takes the ellipsoid heights transformation into orthometric height with GNSS measurements available and easier. It also has a certain precision and sensitivity for the conversion geoid height values must be known. This practice in Trabzon Land Registry IX. Regional Directorate of cadastral works in east-west direction of 80 km, measured orthometric and ellipsoidal heights in the 600 C3 point values created in an area 30 km long north-south direction is used. the point ITRF96 (International Terrestrial Reference Frame-International Terrestrial Reference Network) datums based on 3-dimensional Cartesian coordinates and Gauss Krüger projection coordinates are known. The study is divided into two basis points according to the method and test points. Fulcrums x and y axis directions and the distribution of points is chosen uniformly reflected by the orthometric height. In this study, the polynomial interpolation surfaces, interpolation with multiquadratic surfaces with interpolation surface obtained by the method of weighted average method is used. in selected mainstay, known aware of the ellipsoidal and the orthometric height using the calculated geoid height, calculated orthometric heights for the test points with different interpolation methods, at this point in the known calculating the difference from the known height has made comparisons between the interpolation method