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Showing 5 results for Cm3

, ,
Volume 16, Issue 42 (9-2016)
Abstract

In this research, impacts of climate change on the streamflow hydrological status of the Arazkooseh River are discussed. After Calibration and validation of the LARS-WG, HadCM3 was downscaled under A2 Scenario in three climatology station. Beside, calibration and validation of the SWAT model were done by observed data relative to past period of times. Streamflow values are then predicted using climatic parameters of period of 2011-2030, 2046-2065 and 2080-2099 years via SWAT model. The results indicated that the average annual temperature will increased around 0.8, 1.2 and 4.9 °C in desired periods, respectively. Precipitation values will increased 8.8 and 11.2 percent in the early and mid- century and it will decreased with 7.8 percent in the last years of century, correspondingly. The peak of rainfall will moved from month of March to the December. Because of climate changes, streamflow will increase 13 and 5 percent in the near periods. By contrast, in this case, it will reduce around 18 percent in far future. In this case research, the river discharge will increased in autumn and will decreased in spring seasons. Likewise, results of estimation showed that the annual peak flow will shifted from month of March to the April.


Hasan Zolfaghari, Jafar Masoompourv Samakosh, Shabnam Chahvari,
Volume 18, Issue 49 (3-2018)
Abstract

The purpose of this study is predicting climate changes and investigating the effect of probable climate change on the growing degree-days in the northwest of Iran. For this purpose the climatic data of seven synoptic stations during a 25 years period (1985-2009) was collected including Oroomieh, Tabriz, Zanjan, Sanandaj, Ghazvin, Kermanshah, and Hamedan were used as the base period and thus temperature variations periods (2030-2011 and 2065-2046) through HadCM3 model was simulated. For the little power of temporal and spatial distinction of this model, its outputs were downscaled using LARS-WG software and presented under Emission Scenarios including A1B (moderate scenario), A2 (maximum or pessimistic scenario), and B1 (minimum or optimistic scenario). Calibration, verification and Performance Model with the rate of the adaption of observed data and the simulated measures through statistics , RMSE and MAE were analyzed. Finally, using the simulated temperature growing degree-day was calculated and compared under 4 Base temperature including 0°,5°,10°, and 15° centigrade in the basic span (1985-2009) and future span (2011-2030 and 2046-2065). The results of simulation show that temperature change in north-west areas under all three A1B, A2, and B1 scenario are increasing in the future, but the differences among these three scenarios in each period is inconsiderable. In total the most temperature increasing was detected as 0/7 centigrade in A2 scenario for 2011-2030 period and 2/3 centigrade under A1B scenario for 2046-2065 period. Generally with the temperature increasing, the amounts of growing degree-day without exception increases in review periods and under the four Base temperature. Under studied scenarios, the Bases temperature of 0° centigrade had the most and 15° centigrade had the least impressibility from climate changes, so that the most increasing in calculated degree-day measures under 0° and 15° centigrade bases in the first period to the basic scenario (1985-2009) respectively was simulated as 207/4 and 120/6 degree-day under A2 scenario and for the second period to the 752/5 and 463/5 degree-day under A1B scenario.
 


Tayebeh Dehghani, Mohammad Saligheh, Bohloul Alijani,
Volume 18, Issue 49 (3-2018)
Abstract

In order to detect climate change, a variety of climate indicators can be used which is often considered temperature and precipitation. In order to investigate the effect of climate change on the amount of precipitation in the north coast of the Persian Gulf, it simulated the precipitable water for 2017-2050 based on the RCP4.5 model of the Hadcm3 model. The NCEP / NCAR base-station data with an arc-value of 0.125 was used to analyze the past and present precipitable water patterns and to reveal the process of this time series. Time series analysis of precipitable water was performed using two SENS tilt estimators and Man-Kendall test. The results indicated that the annual time series of rain water was increasing in the region, every year, 0.05 mm, the precipitated water increased and it tended to become more homogeneous, this increase in the significance level of 0.95. The precipitation rate in the eastern part of the region was higher than other areas. Before 1989, several fluctuations were observed in the rainy season of precipitable water, but none was statistically significant at the confidence level of 95%, but since 1989, the trend has increased significantly at a confidence level of 0.95. This spatial behavior of precipitable water can actually have occurred in response to the increase in the overall temperature of the area and can be considered as a profile of climate change in the region.
 

Neamatallah Safarzaei, Alireza Entezari, Mokhtar Karami, Gholamali Khammar,
Volume 22, Issue 66 (9-2022)
Abstract

Today climate change cause increase in concentration of greenhouse gases has been cause increase extreme events and atmospheric hazards. goal of this research, analyze and review climate future is for atmospheric hazards in sistan region. In this study, to simulate minimum and maximum temperature data used from model data CanESM2 under three scenarios (RCP2.6, RCP4.5, RCP8.5) with SDSM statistical scrolling and to simulate rainfall data from the Hadcm3 model under scenarios (A1B, A2, B1) with statistical scrolling LARS-WG. For this purpose, after calibration, validation and data modeling at the selected station, the performance of the model from the viewpoint of the compliance of the base temperature data (1984-2005) and rainfall (1986-2015) with simulation values (2020-2039) evaluated at a significant level of confidence. To adapt base data to simulated data Used of the three criteria root mean square error (RMSE), coefficient of determination (R2) and mean squared error (MSE). According to simulated data were examined four important atmospheric hazard frost, heat waves, extreme precipitation and drought. The results showed that heat waves and drought in the future are serious threats in the region So that in 2021, under release scenario RCP 2.6, Predicted 32 heat waves and the study area will experience more than five heat waves in the year. In addition, most frequent drought forecast in 2020, under release scenario A1B. Extreme precipitation in some years under scenario B1 can be significant threat in the region. Intensity and abundance annual frost under release scenario RCP2.6 more than other scenarios and lower relative to investigated atmospheric threats.

 
Zeinab Mokhayeri, Ebrahim Fatahi, Reza Borna,
Volume 25, Issue 76 (3-2025)
Abstract

To conduct this research, data on monthly synoptic and hydrometric precipitation observations from the National Meteorological Organization and the Ministry of Energy were obtained for a 30-year period (1976-2005). To assess future changes in rainfall, historical data from the period (1976-2005) and simulated climate data from the period (2021-2050) using two models (CM3 and CSIRO-Mk3.6) from the CMIP5 series were used. These simulations were based on four scenarios (RCP2.6, RCP4.5, RCP6, and RCP8.5) with a spatial resolution of 0.5 x 0.5 using the BCSD method. A mean-based (MB) strategy was employed to correct any bias in the model outputs.  The results of the AOGCM models indicated that the CSIRO-Mk3.6 model had a lower error coefficient than the GFDL-CM3 model when simulating precipitation in the Large Karoun case. The average future rainfall (2021-2050) across the entire basin, compared to the average observed rainfall during the statistical period of 1976-2005, exhibited a significant decrease in both the amount and extent of precipitation in both basins for all models and scenarios. In the Great Karoun Basin, heavy rains were consistently concentrated east of the basin across all scenarios and models, with the central foothills experiencing the highest rainfall and the southwest and southeast regions receiving the lowest amounts.  The findings of this study estimate rainfall to range between 83-116 mm, with the highest rainfall expected in the Greater Karoun Basin under the rcp4.5 and rcp2.6 scenarios for both models.


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