Innovative polygon trend analyses with star graph for rainfall and temperature data in agricultural regions of Turkey

Acar E., Kankal M., Akçay F., Şan M.

ENVIRONMENTAL EARTH SCIENCES, vol.81, pp.1-25, 2022 (SCI-Expanded)

  • Publication Type: Article / Article
  • Volume: 81
  • Publication Date: 2022
  • Doi Number: 10.1007/s12665-022-10646-9
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, IBZ Online, PASCAL, Aerospace Database, Applied Science & Technology Source, Aqualine, Aquatic Science & Fisheries Abstracts (ASFA), BIOSIS, CAB Abstracts, Compendex, Computer & Applied Sciences, Environment Index, Geobase, INSPEC, Pollution Abstracts, Veterinary Science Database, Civil Engineering Abstracts
  • Page Numbers: pp.1-25
  • Bursa Uludag University Affiliated: Yes


Agriculture is affected by climate change, such as extreme increases or decreases rainfall and temperature patterns. It is

possible to research that effect by using trend analysis methodologies. This paper investigates trends of monthly total rainfall

and mean temperature data of nine selected stations from agricultural regions of Turkey between 1969 and 2020. To

the end, the classical Mann–Kendall, Innovative Trend Significance Test (ITST), and Innovative Polygon Trend Analysis

(IPTA) with Star Graph methods providing the opportunity to examine seasonal behavior were used for trend analysis. The

analysis reveals that about 96% of all monthly rainfall in the Mann-Kendall test has no trend. However, nearly all stations

tend to decrease (increase) in November (September) in both innovative approaches. For temperature, it is seen that increasing

trend or no trend dominated in general. There were increasing trends in the innovative approaches throughout the year

except for April. Temperatures have increased significantly throughout the year in all regions over the last decades. With

the help of IPTA, it was also concluded that the seasonal internal variability of rainfall over the entire time and in the last

30 years is quite complex and persists in all agricultural regions. The results show that irregular changes in rainfall and rising

temperatures in all stations negatively affected crop yield and/or required more irrigation. In addition, according to the

results obtained by comparing trend methods, innovative approaches are very insistent on determining of trend and provide

additional information through a visual review of trend behaviors.