Tahere Jalali Ansaroodi; Aliakbar Rasouli; Fatemeh Sarafrouzeh; Marzieh Esmaeilpour
Volume 19, Issue 51 , April 2015, , Pages 171-191
Abstract
In this paper, Nisan rainfalls of East Azerbaijan Province in the period of 1980 to 2009 were investigated. Initially changes of Nisan rainfalls trend were analyzed using the non-parametric Mann-Kendall test and Sen's estimator slope that are the most common methods of non-parametric tests. In order ...
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In this paper, Nisan rainfalls of East Azerbaijan Province in the period of 1980 to 2009 were investigated. Initially changes of Nisan rainfalls trend were analyzed using the non-parametric Mann-Kendall test and Sen's estimator slope that are the most common methods of non-parametric tests. In order to predict changes of Nisan rainfalls in the next years, ARMA time series model was used. The results indicated that according to non-parametric tests in the study period, time series of Nisan rainfalls have no trend in none of the stations except Azarshahr. After reviewing of different patterns of ARMA model, proportional model for each station was selected based on Akaike information criterion (ACI) and, the Nisan rainfalls in East Azerbaijan Province were predicted for next 10 years. The accuracy of models was confirmed based on normality tests for residuals of the model and RMSE
Saeed Jahanbakhsh Asl; Batool Zeynali; Tahereh Jalali
Volume 16, Issue 39 , May 2012, , Pages 25-49
Abstract
In this research amount of seasonal effect of the Mediterranean Sea surface temperature (MedSST) has been investigated on seasonal precipitation of East Mountainsides of Zagros and Iran Central basins. For this purpose, warm, cold and base periods were determined for dates of MEDSST[1] in statistics ...
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In this research amount of seasonal effect of the Mediterranean Sea surface temperature (MedSST) has been investigated on seasonal precipitation of East Mountainsides of Zagros and Iran Central basins. For this purpose, warm, cold and base periods were determined for dates of MEDSST[1] in statistics period of (197-2005) for every season. Then statistic Medians of precipitation were determined so as (Rw, RC and Rb)[2] in each period and for all stations. Theses medians in every season and period were compared to specify amounts of these effects. The results indicated when MedSST is colder than base in winter season, precipitation of winter increases in the studied regions, but the temperatures of warmer than base in autumn increase autumn precipitation. Also MEDSST of colder than base of autumn is the cause of precipitation increase in winter and MEDSST of warmer than base of summer is cause of precipitation increase in autumn. The results of correlation analysis indicated that between oscillations of MEDSST and precipitation in winter there is negative correlation, in autumn it is positive correlation and between oscillations of MEDSST in autumn season and precipitation in winter season there is negative correlation. Between anomalies of MEDSST in summer and precipitation of autumn there does not exist any relevant correlation but between increases of autumn precipitation of the study region and warmer than normal MedSST of summer season the trends exist.
[1]- Mediterranean Sea Surface Temperature (MEDSST).
[2]- Rain Median of Warm period, Rain Median of Cold period and Rain Median of Base period of Mediterranean SST.
Majid Rezayee Banafshe; Fatemeh Sarafroozeh; Tahereh Jalali
Volume 16, Issue 38 , February 2012, , Pages 43-74
Abstract
For investigation of variability of climatic elements of UrmiaLake basin, maximum and minimum daily temperature and daily precipitation data over period of 1984-2006 were analyzed. In this paper, 6 indices for analysis of temperature variability and 8 indices for analysis of precipitation variability ...
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For investigation of variability of climatic elements of UrmiaLake basin, maximum and minimum daily temperature and daily precipitation data over period of 1984-2006 were analyzed. In this paper, 6 indices for analysis of temperature variability and 8 indices for analysis of precipitation variability were used. The trends of these indices were specified using least square approach and for identifying their significance nonparametric, Man-Kendal test was used. Results indicate that over the study period climatic conditions have changed. The number of summer days and warm nights significantly increased with the number of cold days and cold nights reduction. Also total annual precipitation, number of precipitation days (above 2 mm) and number of heavy precipitation days (equal or above 10 mm) have significant reduction. Moreover, in the study period the number of consecutive wet days has significant reduction, but increasing of consecutive dry days is not significant.
