Olgu Aydin

Space-time kriging of precipitation variability in Turkey for the period 1976–2010

The purpose of this study is to revaluate the changing spatial and temporal trends of precipitation in Turkey. Turkey is located in one of the regions at greatest risk from the potential effects of climate change. Since the 1970s, a decreasing trend in annual precipitation has been observed, in addition to an increasing number of precipitation-related natural hazards such as floods, extreme precipitation, and droughts. An understanding of the temporal and spatial characteristics of precipitation is therefore crucial to hazard management as well as planning and managing water resources, which depend heavily on precipitation. The ordinary kriging method was employed to interpolate precipitation estimates using precipitation records from 228 meteorological stations across the country for the period 1976–2010. A decreasing trend was observed across the Central Anatolian region, except for 1996–2000 which saw an increase in precipitation. However, this same period is identified as the driest year in Eastern and South Eastern Anatolia. The Eastern Black Sea region has the highest precipitation in the country; after 1996, an increase in annual precipitation in this region is observed. An overall reduction is also seen in southwest Turkey, with less variation in precipitation.

Spatial Patterns of Marriage Migration in Turkey

Even though recent societal phenomena such as a heightened sense of individualism, economic well-being, and institutionalization have caused a shift in peoples life course and made their lives less standard in developed societies, marriage still remains an important life course event in Turkey. Between the years 1995 and 2000 marriage migration comprised 7.4% of the interprovincial migration in Turkey, and of these marriage migrants 94% were woman. Young Turkish women tend toward marriage migration to escape the patriarchal family structure and gain more autonomy, economic security, and well-being. Focusing on the spatial patterns of marriage migration relationships in Turkey, this study seeks to reveal the economic and sociocultural background of male and female marriage migration and to visualize, explore, and model spatial data by using spatial data analysis (SDA) techniques. The results showed that marriage migration in different regions of Turkey varied by gender. Even though SDA techniques have previously been used in other social sciences studies, no other marriage migration study in the literature uses these techniques, thus enabling the article to contribute to the literature.

Trend analysis of annual precipitation of Mauritius for the period 1981–2010

This study researched the precipitation variability across 53 meteorological stations in Mauritius and different subregions of the island, over a 30-year study period (1981–2010). Time series was investigated for each 5-year interval and also for the whole study period. Non-parametric Mann–Kendall and Spearman’s rho statistical tests were used to detect trends in annual precipitation. A mix of positive (increasing) and negative (decreasing) trends was highlighted for the 5-year interval analysis. The statistical tests nevertheless agreed on the overall trend for Mauritius and the subregions. Most regions showed a decrease in precipitation during the period 1996–2000. This is attributed to the 1998–2000 drought period which was brought about by a moderate La Niña event. In general, an increase in precipitation levels was observed across the country during the study period. This increase is the result of an increase in extreme precipitation events in the region. On the other hand, two subregions, both located in the highlands, experienced a decline in precipitation levels. Since most of the reservoirs in Mauritius are located in these two subregions, this implies serious consequences for water availability in the country if existing storage capacities are kept.

Characterising the Seasonal Variations and Spatial Distribution of Ambient PM10 in Urban Ankara, Turkey

The urban airshed of Turkey is under the influence of both traffic and heating emissions. Periodic monitoring and management of air pollution is a must for an up-to-date exposure assessment for effective health and environmental management. The main objective of this paper is to assess the spatial and temporal variability of particulate matter (PM10) in urban areas of Turkey using the metropolitan area of Ankara as a case study, exploring the seasonal variation of PM10 concentrations resulting from indoor heating and transport. This study employed spatiotemporal kriging with external drift to examine the space-time variability and distribution of PM10 concentrations in Ankara for year 2015. The measurements of PM10 in and around metropolitan Ankara were carried out at nine stations. Measurements for the period December 2014 – November 2015 were used and averaged using a 6-h interval for each season: Winter (Dec, Jan, Feb), Spring (Mar, Apr, May), Summer (Jun, Jul, Aug) and Autumn (Sep, Oct, Nov). Population distribution, used as a proxy for indoor heating, and proximity to roads were used as auxiliary variables for kriging analysis. PM10 concentration levels were observed to be highest during autumn and winter. Summer was identified as the “cleanest” period although, in some regions of the city, pollution levels remained high. The southeast region of metropolitan Ankara was identified to be the most polluted region of the city after the city centre.

Türkiye’de su kıtlığının mekânsal ölçekte değerlendirilmesi

Su, dunyanin en onemli dogal kaynaklarindan biridir. Hizli nufus artisi, kentlesme ve sanayilesme suya olan talebi her gecen gun artirmaktadir. Bu durum yakin gelecekte ulkelerin su kaynaklarina ulasmasinda buyuk problemlere neden olacaktir. Gelecekte yasanmasi muhtemel su sikintisina karsi alinabilecek onlemlerin planlanmasinda, ulkelerin su potansiyellerini dogru hesaplanmasi gerekmektedir. Su potansiyelinin belirlenmesinde en onemli faktor, mekânsal ve zamansal olcekte degiskenlik gosteren yagistir. Yagisin dogru tahminini yapabilmek ve mekânsal dagilimini ortaya koymak zordur. Bu zorlugu asmak ve yagisi dogru tahmin etmek icin farkli yontemler kullanilmaktadir. Bunlar arasinda en fazla tercih edilen jeoistatistik yontemlerdir. Jeoistatistik yontemler kullanilarak gerceklestirilen bu calismanin amaclari; Turkiye’nin yagisini gercege uygun hesaplamak, dogru yagis tahmin modelini olusturmak, her bir havza icin yillik ortalama toplam yagis miktarini hesaplamak, 26 havzada kisi basina dusen su miktarini belirlemek ve her bir havzayi Falkenmark su stres indisine gore degerlendirmektir. Bu amacla calismada 1975–2010 donemini kapsayan yillik ortalama toplam yagis verisi ve 26 akarsu havza sinirlari icerisine dusen koylere ait nufus verileri kullanilmistir. Kriging yontemi kullanilarak yagis tahmin modeli olusturulmustur. Yagis modeli Capraz Gecerlilik (Cross Validation) yontemi ile test edilmistir. Turkiye’nin yillik ortalama toplam yagis tahmin haritasi, orografik uzanis ve baki kosullarini iyi bir sekilde yansitmaktadir. Ayrica, Turkiye genelinde yillik ortalama toplam yagis miktari 559.2 mm, toplam yagis miktari 433.9 milyar m3 olarak hesap edilmistir. Bu deger, Turkiye gibi kullanilabilir su acisindan sinirda bulunan bir ulke icin oldukca onemlidir. Calismada daha sonra 26 havzaya dusen yillik ortalama toplam yagis miktari ve kisi basina dusen su miktari hesap edilmistir. Su potansiyellerinin karsilastirilmasinda kullanilan Falkenmark su stres indisine gore, Turkiye’de “mutlak su kitligi” gosteren Marmara, “su kitligi” olan Kucuk Menderes ve “su sikintisi” olan Sakarya Havzalarinin disinda kalan diger 23 havza, “su baskisi yok” kategorisine girmektedir. Turkiye nufusunun buyuk bir kisminin yer aldigi, sanayi ve tarim sektorune ait buyuk yatirimlarin bulundugu bu uc havzada mutlak su kitligi ve su kitliginin yasanmasi ozellikle bu havzalar icin gelecege yonelik su kullanim planlarinin yapilmasini zorunlu kilmaktadir.

Correction to: Landslide susceptibility mapping of the Sera River Basin using logistic regression model

The article “Landslide susceptibility mapping of the Sera River Basin using logistic regression model,” written by Nussaïbah B. Raja, Ihsan Çiçek, Necla Türkoğlu, Olgu Aydin, and Akiyuki Kawasaki, was originally published Online First without open access.

Effects of climate changes on phenological periods of apple, cherry and wheat in Turkey Türkiye’de iklim değişikliğinin elma, kiraz ve buğdayın fenolojik dönemlerine etkileri

It is known that the increase in air temperature from 1980 to present has dramatically changed the phenological periods of the plants in a large part of the world. In this study, the relationships between phenological periods of wheat plant, apple and cherry trees planted large areas in Turkey and climate change were investigated. In this study, the climate and phenological data for 1971-2012 period belonging to the General Directorate of Meteorology were used. The correlation coefficients between temperature and phenological data were calculated, and their trends were examined using Mann-Kendall trend analysis. In Turkey, positive temperature anomalies have been observed since 1994 until present days. Negative relationships were found between phenological periods of apple, cherry and wheat and the average temperatures of February-May period when the plants grow faster. This situation shows that the plants shift their phenological periods to the earlier times in response to the increasing temperatures. The trend calculated for harvest times of apple, cherry, and wheat are -25, -22, -40 days/100 years respectively. It was calculated that an increase of 1.0oC in the temperatures of the February-May period will shift the harvest times of apple, cheery and wheat by 5, 4 and 8 days earlier respectively.