Ceyhan Kahya

Total ozone variation in south eastern Europe

This paper attempts to discuss regional changes in total column ozone over south eastern Europe and the eastern Mediterranean. In this study, we have examined the spatial and temporal variation over the region using the data of five locations in south eastern Europe and one from eastern Mediterranean location. The findings from the region support the stratospheric ozone in mid‐latitudes is strongly influenced by meteorological variability. The highest deviations in total ozone from TOMS overpass data (1979–2003) are seen in winter–spring. This result may be explained by the dynamical influences on ozone over the region in these seasons. Strong correlations found between total ozone and lower stratospheric temperatures (100 mbar) are expected due to both dynamical and radiative processes.

Total ozone over Ankara and its forecasting using regression models

The present study is concerned with the total ozone variation in Ankara, Turkey (39°57′ N; 32°53′ E) and developing a total ozone prediction model by Total Ozone Mapping Spectrometer (TOMS) and single-site aerological data (1984–2006). The daily averages of the total column ozone over Ankara show a seasonal variation, with larger values in spring/winter and lower in autumn/summer and a large day-to-day variability. In this study, in order to forecast the total column ozone over Ankara, a multi-linear regression equation was performed. Predictors are selected by stepwise regression method. The ozone value on the previous day, temperature at the 100 hPa pressure level, previous days temperature for the 700 hPa pressure level and temperature difference for 50 hPa and 500 hPa are the most important predictors. The success of monthly prognostic total column ozone models built up for Ankara is tested by using Brewer MK III Spectrophotometer data and satellite (OMI) data with the upper-air data in 2007. The Brewer MKIII has been in operation since November 2006 in Ankara. The ground-based one-year data show good agreement with the satellite OMI data.

An Examination of the laminae characteristics in ozone profiles in Eastern and South Eastern Europe

This paper discusses the laminae characteristics in vertical profiles of ozone concentrations at three locations representing the Central (Praha, Czech Republic), Eastern (Legionowo, Poland) and Southeastern (Ankara, Turkey) parts of Europe. The total 785 soundings of January 1994‐October 2003 with varied periods were analysed. We found that the lamination is frequent in winter and spring in these locations. The mean magnitude and depth of the laminae in these stations varied depending on the latitudes of the locations. Additionally, in order to understand the influence of tropopause heights on the laminae structure, the number of laminae was grouped according to the high and low tropopause heights. The frequency of laminae for both lower and higher tropopause groups for winter and spring seasons are close to each other.

Improving WRF GHI Forecasts with Model Output Statistics

Solar energy applications need reliable forecasting of solar irradiance. In this study, we present an assessment of a short-term global horizontal irradiance forecasting system based on Advanced Research Weather Research and Forecasting (WRF-ARW) meteorological model and neural networks as a post-processing method to improve the skill of the system in a highly favorable location for the utilization of solar power in Turkey.