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Showing 2 results for Sotoudeh

Dr. Mostafa Karimi, Mis Fatemeh Sotoudeh, Dr. Somayeh Rafati,
Volume 18, Issue 48 (3-2018)
Abstract

Increasing CO2 emissions and consequently, air temperature causes climate anomalies which affects all the aspects of human life. The purpose of this study was to assess the temperature changes and also to predict the extreme temperatures in Gilan and Mazandaran Provinces. To do this, the SDSM statistical and dynamical model was used. As well, it was applied the Mann-Kendal graphical and statistical technique to analyze the temperature changes and its trend. In this regard, the daily temperature was obtained from Rasht, Ramsar and Babolsar synoptic stations during 1961 – 2010, and also the general circulation models data of HadCM3 and NCEP were collected from related databases. The results revealed a significant positive trend in monthly and annual minimum and maximum temperature in all three stations in the first (1961-2010) and third (1961-2040) periods.  There is not a significant trend in extreme temperatures in Ramsar and maximum temperature in Rasht in the second period (2011-2040). The Mann-Kendal graphical test was used for the yearly extreme temperatures in all periods. The results showed that it was occurred both increasing trend and suddenly changes or shifts at the 95% confidence level in all stations. It is occurred the highest of changes in monthly and annual of the minimum temperature at forecasted period (2011-2040). It was predicted extreme temperature to increase about 0.1 to 1.7° C. The short time oscillations and significant positive trend occurred in both the maximum and minimum temperature shows the temperature increase and climate changes in the future. Thus it is obvious the decrease in temperature difference in warm and cold seasons.

 


Zohreh Maryanji, Fatemeh Sotoudeh, Meysam Toulabi Nejad, Ziba Zarrin,
Volume 25, Issue 77 (6-2025)
Abstract

Understanding and predicting future climatic conditions and characteristics is crucial due to their implications for various aspects of life. This research aims to forecast trends in extreme temperatures in the Hamedan region by employing statistical downscaling of general circulation model data. The LARS statistical downscaling model has been utilized to downscale data from the HadGEM2-ES general circulation model and the coupled CMIP5 model under three emission scenarios (RCP2.5, RCP4.5, RCP8.5). Correlation estimates between the simulated and observed data indicate values exceeding 0.95 for all months. Additionally, the p-values derived from statistical tests based on the model outputs demonstrate an acceptable level of performance in data generation and simulation. Consequently, data from 2011 to 2050 were extracted and analyzed for trends. To elucidate changes in trends, the data were examined across three distinct time intervals. The results indicate that in the optimistic scenario (RCP2.5), no significant trend is observed in the average and minimum temperatures. In contrast, significant trends in temperature data are evident under the RCP4.5 and RCP8.5 scenarios, suggesting that the increase in average minimum temperatures reflects severe climatic changes, particularly affecting precipitation patterns during the cold season. Furthermore, the analysis of the trend data reveals a significant increase in average maximum temperatures on both annual and monthly scales across all three examined scenarios, indicating an imminent environmental crisis.


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