Abstract
The main objective of this study is to investigate temperature trend and distribution over 29 years period (1985 to 2013) in Makkah, Saudi Arabia, the holiest city for all Muslims. Monthly mean, maximum, and minimum temperature levels and their trends are investigated using Regression analysis and Theil-Sen nonparametric test. Also, trends in deviations from the reference period (1985-2013) are analyzed. The results showed that the number of hot days and nights increased annually by 1.5966 and 1.832, respectively, while the number of cold nights decreased annually by 0.4054 nights. Both Regression analysis and Theil-Sen test demonstrated positive trends in mean, minimum and maximum temperature levels. Trends are determined for various seasons and months of the year. The annual mean of daily mean, maximum and minimum temperature increased by 0.0398°C, 0.0552°C, 0.0398°C per year, respectively. The minimum value of monthly mean temperature (Tmmean = 23.98°C) was found in January, whereas the maximum value of the mean temperature (Tmmean= 35.95°C) was found in July. Maximum value of monthly mean of daily maximum temperature (Tmmax = 43.88°C) was found in June and minimum (30.54°C) in January. The monthly mean of the daily minimum temperature (Tmmin) varied between a minimum of 18.82°C in January and a maximum of 29.59°C in August. From the above analysis it can be concluded that Makkah is suffering from a considerable warming temperature trend which is confirmed by the Theil-Sen non-parametric test and there is potentially an increasing medical risk from heat waves that will be more intense. This requires specific attention toward: the energy demands for extra cooling, water resources, draughts, and medical preparedness by the decision makers in order to minimize these risks to residents, pilgrims who gather annually to perform hajj rituals and other visitors.
Highlights
Global warming is the most significant environmental problem the world is experiencing today as concluded by the four IPCC Reports [1]-[4]
The minimum value of the monthly mean of the daily mean temperature (Tmmean) of 23.98 ̊C was found in January while a maximum value of 35.95 ̊C was recorded in July
The increasing trend in the annual and the monthly mean of daily mean (Tdmean), daily maximum (Tdmax) and daily minimum (Tdmin) temperatures (Tmmin) determined by regression method have been confirmed by the nonparametric Theil-Sen method
Summary
Global warming is the most significant environmental problem the world is experiencing today as concluded by the four IPCC Reports [1]-[4] Following these reports, several long-term temperature studies have been done on different scales which show that there is a temperature increase globally [5] [6]. Several long-term temperature studies have been done on different scales which show that there is a temperature increase globally [5] [6] They showed that the rate of annual warming for global land areas over the 1901-2000 period was 0.078 ̊C per decade, and as in [7] which showed that the surface temperature of the Earth increased by 0.6 ̊C - 0.8 ̊C during the 20th century. A study over Kuwait [12] showed that the maximum yearly temperature was persistently exceeding its mean value during the last two decades and a considerable warming temperature trend and the rainfall decrease were the main reasons of the aridity in the Middle East which should be considered for rural development and water resources management in KSA [13]
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