چکیده:
This study was conducted to investigate the relationship between the ENSO phenomenon and the monthly and seasonal average air temperature in the southern half of the country over a 55-year period (1951-2005). For this purpose, temperature data from 12 synoptic stations in the country, Southern Oscillation Index (SOI) data, and the Transitory Niño Index (TNI) were used. First, the correlation between air temperature and both ENSO indices was examined at monthly and seasonal time steps, and then the susceptibility of air temperature to the warm (El Niño) and cold (La Niña) phases of the ENSO phenomenon was investigated using the temperature change percentage index. The results showed that the number of stations with a significant correlation between air temperature and the TNI index was considerably higher than with the SOI index. Additionally, in both time scales, the highest significant correlations were negative, indicating a decrease in air temperature with an increase in ENSO index values. Furthermore, based on the TNI index, the air temperature of January, and based on the SOI index, the air temperature of October, were identified as months susceptible to the ENSO phenomenon. On a seasonal scale, most stations had a significant correlation with the ENSO index during the summer season. The correlation range between SOI index values and temperature across all months ranged from a minimum of -0.549 for August to a maximum of +0.463 in October and -0.458 in August and September, up to +0.512 in September for the TNI index. On a seasonal scale, the correlation ranges for SOI and TNI varied from -0.365 in spring to +0.459 in autumn, and from -0.530 to +0.384 in summer, respectively. Using the TNI index as a basis, the percentage of temperature changes at the stations in each phase showed that, on a seasonal scale, the La Niña phase led to a 4% increase in winter temperature, and on a monthly scale, the La Niña phase led to an 8% increase in December temperature. Overall, the results confirm the significant susceptibility of air temperature to the ENSO phenomenon.
خلاصه ماشینی:
First, the correlation between air temperature and both ENSO indices was examined at monthly and seasonal time steps, and then the susceptibility of air temperature to the warm (El Nino) and cold (La Nina) phases of the ENSO phenomenon was investigated using the temperature change percentage index.
Also, in both time scales, the highest significant correlations were negative, indicating a decrease in air temperature with an increase in ENSO index values.
(2007) reported and showed a significant relationship between the temperature of different regions of Khorasan province and the ENSO phenomenon; air temperature had an inverse susceptibility to SOI, such that the average correlation coefficients of temperature with annual and seasonal SOI values were negative.
Thus, the distinct role and feedback of the Southern Oscillation Index (SOI) and the ENSO Transfer Index (INT), as large-scale ocean-atmosphere patterns, on the component changes of mean air temperature in the southern half of the country, were investigated within the framework of statistical correlation methods.
In order to examine the extent to which the temperature changes of each month are affected by the El Nino and La Nina phases, the SOI and INT index values were sorted in ascending order, and the air temperature time series was also rearranged corresponding to both ENSO indices.
Research Findings To detect the relationship between temperature changes in the studied stations and the ENSO phenomenon, a simultaneous comparison of temperature values with the Southern Oscillation Index and the ENSO Transfer Index was performed for monthly and seasonal data.
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