E. Fotaki, Investigation of spatial drought using statistical indexes, Postgraduate Thesis, 141 pages, School of Applied Mathematics and Physical Science – National Technical University of Athens, 2018.
Through the present study rainfall data for specific stations around the world, are processed with the Standard Precipitation Index – SPI. These stations were grouped on the basis of the Köppen climate classification. More specifically, the drought episodes of 83 stations for a period of 50 years for the years 1967-2017 have been studied on a monthly as well as a hydrological year basis. The stations were chosen with a basic criterion not to have large data deficiencies through the period chosen. The stations that experienced extreme drought episodes are Columbia Villavicencio, Colombia National Observatory, Tambacounda of Senegal , Alice Springs of Australia, Santa Rosa of Argentina, Alger Dar El Beiga of Algeria, Alicante of Spain, Sault Ste Marie of the United States , Godthaab and Ammasalic of Greenland, Ethiopian Addis Ababa, Mukteshwar of India , Jimma of Ethipia, and Lander of USA. Next, we compared the nearby stations based on the SPI tables to see if there may be some spatial correlation of drought episodes. The probability of transition from a drought situation to the same or another condition from a three month period to a hydrological year, from a six month period to a hydrological year and from a nine month period to a hydrological year was also calculated selectively for two stations from each climate. Finally, general conclusions are drawn from the entire study.
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