Investigating the Trend of Changes in Temperature extreme in Khuzestan Province

Subject Areas : watere sciences

Hedayat Allah hormozi ¹ , Reza Borna ² , Manijeh Zohourian ³

1 - Department of Geography, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran
2 - Department of Geography, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran (Corresponding Author)
3 - Department of Geography, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran

Received: 2020-01-13 Accepted : 2020-08-21 Published : 2020-03-10

Keywords: Trend, Khuzestan, Kriging, extreme values, Mann Kendall,

Abstract :

Investigation and prediction of climatic extreme values especially temperature is necessary for identifying climatic bottlenecks and opportunities in an area. The increase in greenhouse gas concentrations due to human activities has resulted in global warming and consequently changes in climate extreme indices. For conducting this research, the daily meteorological data of the Iranian Meteorological Organization, including mean temperature, minimum temperature, maximum temperature data for the Khuzestan synoptic stations, for a period of 30 years (1987-2016) were used. Calculation of temperature indices as defined by 1ETCCDMI Expert Group was estimated using RClimdex software. Mann-Kendall nonparametric test was also used to investigate the trend of climate change. Regular and simple kriging method with different models was used to estimate the spatial statistics of temperature data. According to the obtained results, the conventional kriging method with Logical Quadratic Model 2 with the least error rate was selected. The effect of changing the fit indices on the mean monthly temperature ranges from 250 to 314 km. The results of temperature analysis showed that warm indices had an increasing trend which was significant for indices such as summer days, tropical nights, warm days and nights at 5% level. Cold indices have a decreasing trend over the period under study. The results of temperature analysis correspond to the warming of the area and show the decrease in intensity and frequency of cold days and nights.