# Geographical Distribution of Global Radiation and Sunshine Duration over the Island of Cyprus
## 1 Introduction
The first study was based on the hourly values of solar parameters obtained from typical meteorological years (TMYs) for 43 locations in Greece. In his second study, he investigated the sky conditions climatology based on the clearness index (\(k_{t}\)) and diffuse fraction (\(k_{d}\)). For this purpose, he defined the following limits for sky conditions: for clear \(0<k_{d}<0.26\), for intermediate \(0.26<k_{d}<0.78\), and for overcast skies \(0.78<k_{d}<1\). In a recent paper, [PERSON] et al. [32] developed a mathematical method to determine the said limits, using 14 sites from different locations around the world. Another recent study that describes the solar radiation climatology for Camaguey of Cuba was presented by [PERSON] et al. [33]. [PERSON] et al. [34] studied the variation of the radiation indices in Alice of South Africa in order to characterize the solar climate of the area. Regarding Cyprus, an assessment of the solar radiation climate was presented by [PERSON] et al. [35], while a number of works were published in the last five years that investigate the statistics of various shortwave and longwave solar radiation components based on measurements at two locations [6; 36]. An attempt was made by the project Solargis [37] to present an annual map of the island with respect to the average global and direct horizontal radiation, based mainly on satellite data. However, no such study has been conducted for the whole island using ground surface measurements. Therefore, the present work provides an analysis of the global radiation and sunshine duration as well as the classification of sky types based on clearness index. The measurement sites were classified into four categories according to their elevation and their distance from the coast, i.e., coastal (0-300 m], inland plain (0-300 m], semi-mountainous (300 to 800 m] and mountainous (>800 m) locations. The first objective of this work was to assess the measurements obtained by pyranometers and sunshine duration sensors through an extensive quality control procedure and perform statistical analysis on the measured and derived parameters. This information will be useful to engineers concerned to solar energy capture systems and energy efficiency who can therefore take knowledge of the local radiation levels. Furthermore, global radiation can be used to estimate other radiation components such as UV, Reflected, and PAR radiation [36]. The paper is organized as follows: Section 2 describes the materials and methods that were used to estimate extraterrestrial irradiances, including the quality control procedure that was followed for both hourly and daily values. Section 3 presents a detail statistical analysis of global radiation and the derived radiation indices for both hourly and daily values. The analysis covers the daily variation, the monthly variability, the statistical relationships between global radiation and sunshine duration, as well as the geographical distribution of the relevant parameters through isoline diagrams. Section 4 concludes this paper and provides suggestions for future research.