Evaluation of sunshine duration and temporal–spatial distribution based on geostatistical methods in Iran

  • H. Ahmadi
  • F. Ahmadi
Original Paper


The present study made use of daily and monthly sunshine duration hours per day data from Islamic Republic of Iran Meteorological Organization from 1974 to 2005. Various methods have used geostatistical interpolation. With the cross-validation method and analysis of validation criteria, the empirical Bayesian kriging with is future to have better performance for the temporal–spatial distribution. The results indicate there is enough sunshine duration, i.e., 5 h per day during the cold period of the year, and in the warm period, the figure increases to more than 10 h. While sunshine duration has an upward trend, cloudiness shows a downward trend in Iran. The spatial distribution of sunshine duration is strongly influenced by local conditions. On the coast of the Caspian Sea, which has a high latitude and the longest days, the least sunshine duration occurs in all seasons. Even in south coast, which has a lower latitude, a reduction in the sunshine duration hours takes place in warm months because of the cloudiness along the coastal regions. Desert regions with the arid climatic in the center, south and east of Iran enjoy the maximum sunshine duration hours. In the western half of the country due to unevenness density, the number of sunshine hours is less than the eastern half. Eastern, central and southeastern regions in Iran have the most optimal sunshine duration. In general, the sunshine duration increases from north to south.


Cloudiness Empirical Bayesian kriging Geostatistics Iran Sunshine duration Spatial distribution 



The researchers of the study therefore express their gratitude and appreciation to the Islamic Republic of Iran Meteorological Organization (IRIMO) for providing the data of the meteorological stations in this study.


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Copyright information

© Islamic Azad University (IAU) 2017

Authors and Affiliations

  1. 1.Department of Climatology, Faculty of Geography and Environmental SciencesHakim Sabzevari UniversitySabzevarIran
  2. 2.KermanshahIran
  3. 3.Kermanshah Education OrganizationKermanshahIran

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