جستجوی مقالات مرتبط با کلیدواژه « Down scaling » در نشریات گروه « آبخیزداری، بیابان، محیط زیست، مرتع »

TThe industrialization of communities and the rise of greenhouse gases are causing an increase in the temperature of the earth and other climate parameters. This phenomenon is the most important problem of the planet in the present century, hence the assessment of the extent of its formation on a global and regional scale is of particular importance. So far, several General Circulation Model (GCM) has been designed to predict future climate change, but the outputs from these models cannot be used because of the localization on a local scale. So various methods have been developed to use the outputs of these models on a regional and local scale. In this research Statistical Downscaling Model (SDSM) was used to evaluate the changes in temperature indices in the Agh-Chay watershed. In order to, the efficiency of this model was evaluated for downscaling of the temperature indices in Khoy synoptic station and the indices were simulated until 2100. The SDSM model was calibrated and validated by using Khoy station observation temperature and national center environmental prediction data. For evaluating the model, mean absolute error and root mean squared error was used and after obtaining the efficiency of the model the outputs of the HadCM3 model, the duration of 2020-2050, and 2070-2100 under the A2 and B2 scenarios were downscaled with SDSM statistical model respectively. The results show the increasing of the minimum and maximum temperature in the study area in most of the months. The maximum temperature was up to 3.48 ° C in the period 2020-2050 and up to 5.6 ° C during the period 2070-2100 and the minimum temperature up to 3.45 ° C for the period 2020-2050 and up to 5.51 for the period 2070-2100. The results also show an increase in precipitation in most months of the year from 2050 to 2020 period (in the range of 0.1 to 95.74). Rainfall changes from 2100 to 2070 period are in the form of an increase in most months of the year with a maximum of 94.64 and a minimum of 1.34 percent.

Climate change affects severity and duration of drought, peak, magnitude, and frequency of the events in the coming decades. Iran is one of the countries that have suffered the most from drought. Therefore, drought monitoring and forecasting is crucial for drought mitigation and preparedness strategies in future. This study was conducted to evaluate the status of drought characteristics of severity, duration, magnitude, and peak in historical period from1966 to 2015 and future from 2016 to 2050  for 39 synoptic stations in Iran using Standardized Precipitation Index (SPI). Also, for future simulation, the output of the general circulation model of CanESM2 based on two scenarios RCP4.5 and RCP8.5 and the statistical downscaling method of SDSM were used. Results showed that the trend of severity, duration, magnitude, and peak  have no any significant trend. The SPI zoning map shows an increase in the historical period but will decrease in the future period under two scenarios. The results of the trend analysis of the severity, duration, and magnitude and peak drought showed that there is no significant trend in the historical and future in Iran. However, most of these characteristics are increasing in the northern, northeastern, western, and southern parts of Iran. Finally, the southern parts of Iran including Hormozgan and Sistan and Baluchestan provinces, the northeastern and western parts of Khorasan Razavi, Golestan, and Azerbaijan provinces will be most vulnerable to climate change. Therefore, the risk of drought in these regions is high and it is necessary to seriously plan for the management of natural resources, and agriculture.

The effects of a change in the temperature and particularly precipitation around the world are not well known due to their complexity and spatial variations. In this research, the impacts of climate change on some climatic variables (temperature and precipitation) has been studied  in Hableh Roud Basin due to ecological sensitivity and special situation of this area and HadCM3 model data were analyzed using LARS-WG model according to A2, B2 and A1B scenarios. The seasonal variations of precipitation, minimum and maximum temperature of the synoptic stations of Firouzkooh and Garmsar were investigated in two periods of 2030-2011 and 2046-2065. Results showed that precipitation between 0.23 to 0.48 mm will increase in the near future and will decrease between 0.08 to 0.15 mm in the middle future. The minimum temperature will increase between 0.5 to 0.67° C in near future and between 1.54 to 1.97° C for the middle future. Maximum temperature will increase in near future between 0.43 to 0.6° C and between 1.47 to 1.89° C in middle future. Finally, the climatic conditions of the Hableh Roud Basin will have a significant difference compared to current conditions in upcoming periods. Therefore, regarding to this issue, as well as awareness of the direct and indirect negative effects of climate change in the various parts of the basin (agriculture, water resources, environment, natural resources, health, industry and economics), long-term planning and strategic management of new situations is essential.

Temperature is one of the most important meteorological parameters that can be used in many case studies. This parameter is of particular importance in the study of climate change and agriculture, So that climate change and rising temperatures is considered one of the most important environmental issues of human. Zoning of this parameter and study its changes can be effective in the correct management of soil and water resources and supply water requirement. This research studies the consequences of the climate change on the rainFall pattern in Ardebil province in the next three decades using the output data of the AOGCM model (hadcm3) under A1B scenario. Finally, the zoning of the temperature patterns changes were obtained in these periods. The results showed that there will be a significant upward trend in the temperature of the province. Moreover, in the third decade, Kosar station would be in the best condition with 0.35-3.13°C increase in temperature, and Sarein would be in the worst condition with 0.68-3.84°C increase in temperature.