Bostan, P. A.
Akyürek, Sevda Zuhal
In this study, mean annual precipitation and temperature values observed at 225 meteorological observations over Turkey are used to disclose spatial distribution of mean annual precipitation and temperature values. Data components were obtained from the Turkish State Meteorological Service for 34 years period (1970-2003). The basic objectives of the study are: to infer the nature of spatial variation of precipitation and temperature over Turkey based on meteorological observations and to model the pattern of variability of these data components by using secondary variables extracted from SRTM and river network. Modeling the spatial distribution of data sets is implemented with Co-kriging (COK), Ordinary Least Squares (OLS) and Geographically Weighted Regression (GWR) techniques with using secondary variables such as elevation, aspect, distance to river, roughness, drop (elevation differences between station and grid), sd-grid (standard deviation of 5*5 km grid), and plan-profile curvature. Correlations among the listed variables were analyzed and highly correlated ones were removed from the analysis. The study found a presence of high spatial non-stationary in the strength of relationships and regression parameters. The co-kriging interpolation method gave strong relationship for temperature (r(2)= 0.823) but comparatively weak relationship for precipitation (r(2)= 0.542). OLS method resulted with lower relationships for temperature (r(2)= 0.68) and for precipitation (r(2)= 0.3). The highest adjusted r(2) values were obtained with GWR method; 0.96 for temperature and 0.66 for precipitation.
Joint International Conference on Theory, Data Handling and Modelling in GeoSpatial Information Science


Comparison of regression and kriging techniques for mapping the average annual precipitation of Turkey
Bostan, P.A.; Heuvelink, G.B.M.; Akyürek, Sevda Zuhal (Elsevier BV, 2012-10)
Accurate mapping of the spatial distribution of annual precipitation is important for many applications in hydrology, climatology, agronomy, ecology and other environmental sciences. In this study, we compared five different statistical methods to predict spatially the average annual precipitation of Turkey using point observations of annual precipitation at meteorological stations and spatially exhaustive covariate data (i.e. elevation, aspect, surface roughness, distance to coast, land use and eco-region)...
Decadal variability analysis of extreme precipitation in Turkey and its relationship with teleconnection patterns
Düzenli, Eren; Yılmaz, Mustafa Tuğrul; Willems, Patrick; Department of Civil Engineering (2017)
Natural disasters as droughts and floods originate as a consequence of excessive decrease or increase in precipitation amount and/or frequency, while the variability in the climate significantly impacts the expected change in precipitation. Given that many global ocean-atmosphere teleconnection patterns (AO, WeMO, NAO, SOI, etc.) are tightly related with the climate variability and show decadal/multi-decadal oscillations, it is important to analyze precipitation variability at the decadal time-scale to unde...
Comparison of MODIS-derived land surface temperature with air temperature measurements
Georgiou, Andreas; Akcit, Nuhcan (2017-03-23)
Air surface temperature is an important parameter for a wide range of applications such as agriculture, hydrology and climate change studies. Air temperature data is usually obtained from measurements made in meteorological stations, providing only limited information about spatial patterns over wide areas. The use of remote sensing data can help overcome this problem, particularly in areas with low station density, having the potential to improve the estimation of air surface temperature at both regional a...
Impacts of climatic variables on water-level variations in two shallow Eastern Mediterranean lakes
Yagbasan, Ozlem; Yazıcıgil, Hasan; Demir, Vahdettin (2017-08-01)
Variations in temperature and precipitation have direct impacts on the physical, chemical and biological characteristics of the shallow lakes. This paper examines the possible linkages between climate variables and the water levels of shallow interconnected Lakes Mogan and Eymir, located 20 km south of Ankara in Central Anatolia. The variations in the lakes' water levels during 1996-2015 are studied and the impacts of climate variables on the lake levels are assessed to address the long-term consequences. T...
Performance evaluation of satellite- and model-based precipitation products over varying climate and complex topography
Amjad, Muhammad; Yılmaz, Mustafa Tuğrul; Yücel, İsmail; Yılmaz, Koray Kamil (Elsevier BV, 2020-05-01)
Accuracy assessment of precipitation retrievals is a pre-requisite for many hydrological studies as it helps to understand the source and the magnitude of the uncertainty in hydrological response variables, particularly over regions with complex topography. This study evaluates GPM IMERGv05, TMPA 3B42V7, ERA-Interim, and ERA5 precipitation products using 256 ground-based gauge stations between 2014 and 2018 over Turkey known to have complex topography and varying climate. Error statistics, categorical perfo...
Citation Formats
P. A. Bostan and S. Z. Akyürek, “SPATIO-TEMPORAL ANALYSIS OF PRECIPITATION AND TEMPERATURE DISTRIBUTION OVER TURKEY,” Hong Kong, PEOPLES R CHINA, 2010, vol. 38, Accessed: 00, 2020. [Online]. Available: