Mahmut Cetin - Academia.edu (original) (raw)

Papers by Mahmut Cetin

MAUSAM

Identification of spatiotemporal tendencies of climate types may help water managers mitigate the... more Identification of spatiotemporal tendencies of climate types may help water managers mitigate the negative impacts of droughts on water-demanding sectors. The primary objective of this study was to figure out the spatiotemporal tendencies of climatetypes in Sanliurfa province by using Erinc’s aridity index (EDI). To that end, long-term (1965-2018) annual precipitation and average annual maximum temperature series of meteorological stations were obtained and utilized to calculate the EDI series on a yearly basis. The EDI series of each station was divided into three periods, non-overlapping and successive, i.e., P1 (1965-1981), P2 (1982-1999) and P3 (2000-2018). Outliers were detected, andremoved from the EDI series; missing data were completed by regression analysis. The Markov transition probability matrix of the climate classes for the three periods was estimated for each station. Maps of the initial probability vectors and steady-state probabilities for the three periods of each ...

Turkish Journal of Agriculture and Forestry, Aug 25, 1999

Bu çal›flmada, Do¤u Akdeniz bölgesi ve geçit kufla¤›nda yer alan ya¤›fl gözlem istasyonlar›n›n uz... more Bu çal›flmada, Do¤u Akdeniz bölgesi ve geçit kufla¤›nda yer alan ya¤›fl gözlem istasyonlar›n›n uzun y›ll›k ayl›k noktasal ya¤›fl gözlemlerinin uzaysal de¤iflkenlik yap›lar› jeoistatistiksel yöntemle belirlenmifltir. Belirlenen ayl›k yar›variogram modelleri kullan›larak, Çukurova bölgesinde yer alan Tarsus Ovas› için uzun y›ll›k ayl›k ortalama alansal ya¤›fl de¤erleri blok kriging tekni¤i ile türetilmifltir. Türetilen alansal ya¤›fl de¤erleri zaman serisi analizine tabi tutularak ortalama ve standart sapma etraf›ndaki periyodik bileflen giderilmifl, art›k terimlerin birbirinden ba¤›ms›z ve lognormal da¤›l›ma uydu¤u χ 2 testi ile belirlenmifltir. Lognormal da¤›l›m fonksiyonu kullan›larak, Tarsus Ovas› alansal ya¤›fl serisinin standart yinelenme y›llar› için aylara göre yinelenme y›l›-ya¤›fl e¤rileri gelifltirilmifltir.

Turkish Journal of Engineering and Environmental Sciences, Jul 20, 1998

Dicle üniversitesi mühendislik fakültesi mühendislik dergisi, Apr 5, 2018

Artan dunya nufusu ve kuresel iklim degisikligi, suya olan ihtiyacin her gecen gun artmasina nede... more Artan dunya nufusu ve kuresel iklim degisikligi, suya olan ihtiyacin her gecen gun artmasina neden olmakta; icme suyu, sulama suyu ve kullanma suyu kaynaklarinin korunmasi ve kontrol edilmesi icin yeni yontemlerin gelistirilmesini zorunlu kilmaktadir. Bu calismada, rezervuar yuzey alanlarinin ve rezervuar su kotlarinin belirlenmesinde uzaktan algilama ve cografi bilgi sistemlerinin kullanilma olanaklarinin arastirilmasi amaclanmistir. Calisma, Seyhan Havzasinda bulunan Seyhan, Catalan, Nergizlik baraj golleri ile Ceyhan Havzasinda yer alan Kozan ve Mehmetli (Kesiksuyu) baraj gollerinde yurutulmustur. Landsat 8 uydusuna ait goruntulere Modifiye Edilmis Normalize Fark Su Indeksi (MNDWI-Modified Normalized Difference Water Index) indeksi uygulanmis ve bu indeksten yararlanilarak baraj gollerinin yuzey alani hesaplanmistir. Hesaplanan alanlar kullanilarak, baraj gollerine ait kot-alan cetvellerinden gol kotlari tahmin (GKhesap) edilmistir. Uydu goruntulerinin cekildigi tarihlerdeki gercek rezervuar su kotlari (GKolcu), Gol Gozlem Istasyonlari (GGI) kayitlarindan elde edilmistir. GKhesap ile (GKolcu) arasinda, yuksek korelasyon bulunmustur. Olculen ve hesaplanan rezervuar su kotlari arasindaki hatalar, rezervuar yuzey alani ile ters iliskili bulunmustur. Ortalama hatalar Seyhan baraj golunde 0.33 m, Catalan baraj golunde 0.31 m, Kozan baraj golunde 1.21 m, Mehmetli (Kesiksuyu) baraj golunde 1.11 m ve Nergizlik baraj golunde 1.51 m hesaplanmistir. Rezervuar alani buyudukce, hatalar azalmistir. Ozellikle ulasim, topografya ve iletisim gibi sebeplerden dolayi GGI’nin isletilmesinin zor oldugu baraj ve goletlerdeki su kotlarinin tahmin edilmesinde, Landsat 8 uydu goruntulerinden yararlanilabilecegi sonucunu varilmistir.

Tarım Makinaları Bilimi Dergisi, Apr 1, 2012

Hydrological Sciences Journal

Tarım Bilimleri Dergisi

Determination of cropping pattern is a very important factor in quantifying irrigation water requ... more Determination of cropping pattern is a very important factor in quantifying irrigation water requirements at a catchment scale. In this regard, remote sensing is a robust tool for generating spatial-temporal variation of crops. This study focuses on crop classification by using remotely sensed data coupled with ground truth data. Therefore, this study aimed at both classifying each crop type and calculating crop evapotranspiration (ETc) based on reference evapotranspiration (ETo) by using the Penman-Monteith evapotranspiration model and crop coefficient (Kc). ETo was estimated by using data from two meteorological stations located in the study area. To this end, this study was conducted in Akarsu Irrigation District (≈95 km2), a sub-catchment in the Lower Seyhan Plain (LSP), in the 2021 hydrological year. Ground truth data were collected in the two growing seasons. The ENVI program was used to classify crop types from Sentinel 2A-2B satellite images with 10-m by 10-m spatial resolut...

DergiPark (Istanbul University), Nov 29, 2022

In this study, Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotra... more In this study, Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI) were employed for drought characterization by using precipitation and temperature data series at a 3-month timescale. In addition, correlation coefficients between SPEI and SPI were calculated for twenty meteorological stations located over the Black Sea region of Turkey and were assessed to decide the representative nature of drought indices. Results showed that there is a remarkably strong correlation between SPEI and SPI. The correlation coefficient is equal to or greater than 0.93 in coastal areas, but a gradual decrease in relatively dry zones. The highest and lowest correlations were found to be 0.98 and 0.82 for Rize station located by the sea and the Gumushane station away from the sea, i.e., in the inland region, respectively. Research results suggested that data availability and the site-specific conditions of the region should be taken into account when using indices.

Uzaktan algılamanın en önemli uygulama alanlarından biri evapotranspirasyon haritalarının üretilm... more Uzaktan algılamanın en önemli uygulama alanlarından biri evapotranspirasyon haritalarının üretilmesidir. Genel olarak, FAO Penman-Monteith, Hargreaves veya Blaney-Criddle gibi klasik teknikler kullanılarak gerçek evapotranspirasyon (ETa) hesaplamaları noktasal olarak yapılmaktadır. Ancak suyun daha etkin kullanılabilmesi için gerçek evapotranspirasyon haritalarının kullanılması gerekmektedir. Literatürde, evapotranspirasyon haritalama için temel veri kaynağı olarak çok kanallı uydu görüntülerini ve meteorolojik verileri kullanan TSEB, 3T ve SEBAL gibi teknikler bulunmaktadır. Bu yöntemlerden arasında yer alan SEBAL tekniği, dünyanın birçok bölgesinde uygulandığı için kendini kanıtlanmış bir yaklaşımdır. Bu teknik daha önceleri Landsat 5, Landsat 7, Aster, MODIS, AVHRR gibi uydu görüntüleri ile kullanılmış olmasına karşın, Landsat 8 (LDCM) ile kullanımına rastlanılmamıştır. Bu çalışma kapsamında SEBAL tekniği Landsat 8 (LDCM) uydu görüntüleri ile birlikte kullanılmıştır. SEBAL tekniğ...

Bu arastirmanin amaci; Standardize Yagis Indeksi (SYI) yontemi kullanilarak frekansi 2 ve 10 yil ... more Bu arastirmanin amaci; Standardize Yagis Indeksi (SYI) yontemi kullanilarak frekansi 2 ve 10 yil olan bolgesel meteorolojik kuraklik haritalarinin elde edilmesi ve bu haritalar yardimiyla kuraklik riski olan bolgelerin belirlenmesidir. Arastirma, 21 470 km² genisligindeki Seyhan Havzasinda yurutulmustur. Havza sinirlari icerisinde ve yakininda bulunan 41 adet meteoroloji gozlem istasyonundan temin edilen uzun yillar aylik toplam yagis serileri incelenmistir. Istasyonlarin gozlem yili icerisindeki eksik verileri, aylik veriler kullanilarak regresyon analiz teknigi ile tamamlanmistir. Istasyonlardan elde edilen aylik ve yilik toplam yagis serileri kullanilarak SYI elde edilmistir. Yillik yagislara iliskin SYI serileri frekans analizine tabi tutulmustur. Uygun olasilik dagilim modelleri %5 onem duzeyinde Kolmogorov-Smirnov uygunluk testi ile saptanmistir. Olasilik dagilimlarindan her istasyona ait 2 ve 10 yil yinelenmeli SYI degerleri belirlenmistir. Bu degerler kullanilarak Ocak-Arali...

Aims: The primary objective of this study was to figure out spatio-temporal tendencies of climate... more Aims: The primary objective of this study was to figure out spatio-temporal tendencies of climate-types in Şanliurfa town and its environs, located in the Southeastern Anatolia Project (GAP) area, through using Erinc Drought Index method. Methods and Results : Data sets consisting of long-term (1965-2018) annual total precipitation as well as average annual maximum temperature series of Şanliurfa, Birecik, Akcakale, Ceylanpinari, Siverek and Bozova meteorological stations -distributed unevenly over total surface area of 19 242 km²- were obtained and utilized in order to calculate Erinc Drought Index (EDI) on a yearly basis. EDI time series of each station was divided into three non-overlapping and successive parts or periods, i.e. period-1 (1965-1981), period-2 (1982-1999), period-3 (2000-2018). The best fitting probability distribution models to the EDI series of each period were, in turn, determined by performing a regular frequency analysis procedure by Kolmogorov-Smirnov Goodnes...

Yillik akis rejiminin bir bileseni olan dusuk akimlar yilin belli zamanlarinda akarsuda gorulebil... more Yillik akis rejiminin bir bileseni olan dusuk akimlar yilin belli zamanlarinda akarsuda gorulebilmektedir. Dusuk akimlarin akarsudan su saglanmasi, su kalitesi, ulasim ve canlilarin yasami uzerinde etkileri vardir. Bir akarsu havzasinda dusuk akimlarin uzun bir sure devam etmesi durumunda havzada kurakligin meydana gelme olasiligi artar. Bu donemlerde suyun ne sekilde kullanilacagina karar vermek icin dusuk akimlarin incelenmesi onem tasir. Kurak donemlerde her turlu maksatla kullanilacak suyun miktarinin belirlenmesinde bir arac olarak kullanilmak uzere dusuk akim ile ilgili calismalar yaygin olarak yapilmaktadir. Frekans analizi bu amacla kullanilan bir yontemdir. Bu calismada, Meric-Ergene, Gediz, Seyhan ve Ceyhan havzalari icin dusuk akim frekans analizi yapilmistir. Dusuk akimlarin frekans analizinde 2- ve 3-parametreli Gamma, log-normal ve Weibull dagilimi ile Genel Ekstrem Deger dagilimi secilmistir. Dusuk akimlari temsil etmede Meric-Ergene, Gediz ve Ceyhan havzalarinda cogu...

Tarım Bilimleri Dergisi, 2021

Groundwater is a major drinking water resource in arid coastal regions. The groundwater quality o... more Groundwater is a major drinking water resource in arid coastal regions. The groundwater quality of Bosaso city experienced degradation due to rapid urbanization and industrialization. This study was carried out to delineate the spatial distribution of groundwater quality parameters and evaluate groundwater suitability for drinking and irrigation uses. The groundwater samples were collected from Bosaso Plain to determine the pH, electrical conductivity (EC), total dissolved solids (TDS), and sodium and chloride concentrations. To categorize water quality for irrigation purposes, sodium adsorption ratio (SAR) was calculated. Ordinary kriging procedure was performed in order to map the spatial distribution of groundwater quality parameters. The interpretation of laboratory analysis results revealed that the most of groundwater wells in the study area is unsafe for drinking purposes due to high salinity, except for the central area (Biyo Kulule). In terms of irrigation uses, the minor area may be under the risk of alkalinity or sodium hazard. However, all groundwater supply points are not suitable for irrigation due to the salinization risk and can be only used to irrigate high salttolerant crops. The final maps show that the groundwater quality decreases from southeast to the north of the plain. This indicates that the groundwater is probably subjected to the seawater intrusion. In this regard, the implementation of a groundwater monitoring program is necessary to achieve concrete results. Nevertheless, the most suitable groundwater quality is found to be at the central part of the Bosaso plain.

Turk. J. Agric. For, 1999

Dünyam›z 2000'li y›llara girerken pek çok ülkede tehlikeli boyutlara ulaflan yetersiz beslenme ve... more Dünyam›z 2000'li y›llara girerken pek çok ülkede tehlikeli boyutlara ulaflan yetersiz beslenme ve açl›k sorunu da büyüyerek devam etmektedir. Örne¤in; Eswaren (1) Afrika'da 29, Güneybat› Asya'da 15, Orta Amerika'da 14 ve Güneydo¤u Asya'da 6 ülke olmak üzere toplam 64 ülkede yaflayan milyonlarca insan›n besinlerini ço¤unlukla kendi topraklar›ndan karfl›layamad›¤›n› bildirmektedir.

Politeknik dergisi, Mar 15, 2022

İklim değişikliği, kuraklık gidişinin alansal ve zamansal yayılımının izlenmesinde farklı yaklaşı... more İklim değişikliği, kuraklık gidişinin alansal ve zamansal yayılımının izlenmesinde farklı yaklaşımları ortaya konarak analitik çözümlemeleri ihtiyaç haline getirmiştir. Güneydoğu Anadolu Projesi (GAP) kapsamında; 19 242 km²'lik büyüklüğü ile sulama alanlarının %50'sine sahip Şanlıurfa'da yürütülen bu çalışmada, farklı yöntemler kullanılarak meteorolojik kuraklığın alansalzamansal eğiliminin ve büyüklüğünün (hızının) belirlenmesi amaçlanmıştır.

Bu calismada, tarimsal bir alan gridler yardimiyla matrislere donusturulerek Taban Suyu Derinligi... more Bu calismada, tarimsal bir alan gridler yardimiyla matrislere donusturulerek Taban Suyu Derinligi (TSD) icin grid tabanli yeni bir optimizasyon modeli gelistirilmistir. Amac fonksiyonu, Ceza Puani olarak adlandirilan TSD olcumlerinin bilgi kaybini veren ortalama (M)+standart sapma (STD) istatistiginin minimize edilmesidir. Arastirma, Asagi Seyhan Ovasinda 9 495 ha alanda yurutulmustur. Arastirmada, 107 adet drenaj gozlem kuyusunda 3 yil boyunca 12 kez olculen TSD verileri kullanilmistir. Mevcut 107 kuyu seti ile (KD_107) havzada 12 donem gozlemlenen TSD degerleri ve farkli Kombinasyon Kuyu Dagilimlarinin (KKD) ayni donem TSD degerleri Ters Uzaklik Yontemi (TUY) ile haritalanmistir. Olusturulan haritalar (havza matrisleri) arasinda KD_107 havza matrislerinin 12 donemini temsil eden M ve STD degerleri referans alinarak KKD’lerin bilgi kayiplarini veren CP=M+STD belirlenmistir. Minimum bilgi kaybini veren 23 farkli KKD (kuyu seti) optimize edilmistir. Mevcut 107 kuyu ile gozlem yapilan...

This work was carried out in Akarsu Irrigation District (AID) of 9 495 hectares. Drainage and gro... more This work was carried out in Akarsu Irrigation District (AID) of 9 495 hectares. Drainage and groundwater salinity problems developed due to mismanaged irrigation systems, low irrigation efficiency, heavy soil texture, inadequate drainage systems and other likely problems which all cause reduced agricultural production. The undertaken work investigates interrelations between the existing irrigation practice with groundwater depths and salinity, using groundwater observation wells. With additionally installed drainage observation wells, a total of 107 wells were under survey in 2006. The groundwater depths were measured in May and July and samples were collected concurrently for measuring electrical conductivity (EC, dS m-1). The groundwater depths in May showed that there was no drainage problem in the area. However, drainage problem (ground water depth < 1 m) was evident during high irrigation season in July. Mean groundwater salinity in May and July were respectively 4.3±10.1 a...

Agricultural output globally is largely dependent on fertilizer use, particularly nitrogen (N), e... more Agricultural output globally is largely dependent on fertilizer use, particularly nitrogen (N), especially in irrigated cropping. While a substantial amount of the applied N is taken up by the crop to stimulate growth and yield, much of it does not positively affect crop growth due to losses by leaching, volatilization, denitrification, and immobilization. Thus, N fertilizer-use efficiency is less than optimum in most production systems. Loss of N by leaching to the groundwater has economic, health and environmental implications. In a study area with poor drainage outlet conditions due to the low-lying drainage basin, Yemisli Irrigation District in the Cukurova region of southern Turkey, we determined the variability over space and time of ground-water nitrate (NO3) concentrations during years 2007 and 2008. Relatively shallow groundwater observation wells (56), up to 3 meters deep, were dug at various locations to represent the most common crops and soils in the irrigation district. Groundwater depth was measured, and water samples were collected (five times in 2007 and four times in 2008) and analyzed for NO3 concentration. Regional maps of groundwater depth and NO3 concentration were developed from the point data by using the inverse distance- squared interpolation technique. Groundwater NO3 concentrations ranged between 0.78 and 56.38 mg L-1 in 2007 and between 1.48 and 52.79 mg L-1 in 2008, only exceeding the critical 50 mg L -1 concentration in 0.4 to 5.4 % of the wells, depending on the sampling dates The NO3 concentrations were highest in February and in June-July. The peaks suggest that there is a likelihood that in the early part of the wheat cropping season (February), NO3 could be leached by the high rainfall in winter; similarly, N losses can occur by irrigation in June-July during the growth of cotton (Gossypium hirsutum) and corn (Zea mays). In most of the area (>60% of total), groundwater NO3 concentrations ranged from 20 to 50 mg L-1, and were thus marginal relative to the threshold pollution level (30 mgL-1). As both N fertilizer use and the extent of irrigation are likely to increase in this region of Turkey, so too will the poor drainage conditions inevitably continue. Consequently, regular groundwater NO3 monitoring, as adopted in this study, is advisable, and is also applicable to irrigated areas in other regions of the world. © by PSP