مدل سازی فراسنج های اقلیمی استان خراسان جنوبی

Introduction
Climate change has played an important role in all aspects of human life. Therefore, climate
predictions in atmospheric general circulation models (GCM) will have particular importance.
In this study, downscaling by A1B scenarios, IPCM4 and BCM2 of atmosphere general
circulation models in LARS-WG model are used for analysis of climate change impacts on
maximum and minimum temperature, solar radiation and precipitation. The data have been
gathered from 7 Synoptic stations in province of Southern Khorasan. For this purpose,
assessment process of simulation and observation data are conducted by three steps, including
calibration, validation and modelling. To evaluate the agreement between the observed and
simulated data, two indexes were used; Root Mean Square Error (RMSE) and Coefficient of
Determination (CD). The results of analysis in Makesens, Sin’s Estimator and Mann-Kendall
showed that minimum temperature, maximum temperature and evapotranspiration in all stations
will be increased in years of 2011-2060. The results have shown that rainfall in all stations
(except Ghaen station) will be decreased and solar radiation in all stations (except Ghaen and
Ferdous station) will also be increased. Increasing trend in temperature in Birjand and Ghaen
station will be lower and in Tabas Station will be higher. It may be appeared that weak changes
in climatic parameters in some stations are related to specific geographical conditions and
topography of this region.
Climate change in the past and today would change the pattern of human life and it seems
that humans and their activities are causing the global climate change. Uncontrolled growth of

population, transportation and other human activities, particularly pollution resulted from
industries lead to major changes in climate. After the industrial revolution changes in global
climate such as increases in extreme climatic events have appeared due to the excessive use of
fossil fuels and land use change. At present, this variability has become a major concern of
climatologists and weathermen. Therefore, attention to researcher long term forecast about
climate parameters for change value help decrease the effects of ill climate change.
Atmospheric general circulation models to assess future climate is one of the common methods.
Meanwhile, LARS-WG model as one of the general circulation models of the atmosphere is
important for future climate change and has led to some efforts by many scholars. The high
accuracy of climate data modelling in different climatic stations has been confirmed by many
researchers.
Methodology
In this study at first, daily statistics including minimum temperature, maximum temperature,
rainfall and radiation related to 7 Synoptic stations in province of Southern Khorasan were
obtained from meteorological organization of Iran (Table: 1).
Table 1: Geographical characteristics of the sample stations
Stations LON LAT ElE
Birjand 59 12 32 52 1491
Boshruyeh 57 27 33 54 885
Ferdous 58 10 34 10 1293
Ghaen 55 05 33 47 845
Khour 58 28 32 56 1117
Nehbandan 58 48 36 16 1213
Tabas 56 55 33 36 711
In Second step, some weather data have been produced by using parameters listed in Lars
models. Two BCM2 IPCM4 models for each synoptic station in South Khorasan are used in this
study to arrive target modeling data under scenario A1B. After entering data into the model
Lars-wg and getting the trends in the observed time series data, we have attempted to reproduce
the data at the stations during 2011- 2060.. Finally, the simulated data are compared with
observed data using statistical analysis and graphing. They have also examined the ability of the
model to simulate meteorological data in stations. The Root Mean Square Error (RMSE) and
coefficient of determination (CD)have also been applied. If the RMSE values are closer to zero,
this indicates the observed and simulated values are closer to each other and to be more precise
answers in each step.
Results and Discussion
The results of the research showed that BCM2-A1B models in Birjand, Boshruyeh, Ferdous,
Nehbandan and Tabas and IPCM4-A1B models in Ghaen, have the lowest simulated values.
Distribution of annual minimum temperature simulated for the period 2011-2060 shows that the
Physical Geography Research Quarterly, 46 (3), Fall 2014 11
minimum temperature in southern Khorasan province is 0.02 per year and the coefficient of
determination of 0.09 is increasing and that the minimum temperature during the five decades
can be changed between 11.4 to 12.9 degrees. The simulations conducted by LARS-WG models
over the next fifty years will change in the average of minimum temperature among the
Synoptic stations of provinces, from 7.5 degrees in Ghaen to 17 degrees in Tabas. The average
of maximum temperature will also change from 23 degrees in Ghaen to 30 degrees in Tabas. In
province of South Khorasan, the average of minimum temperature is 12 degrees and the average
of maximum temperature is 26.6 degrees. Increasing trend of temperature in Birjand and Ghaen
stations will be lower and in Tabas Station higher. Obviously, due to the lower temperature, the
cities of Ghaen and Birjand will experience more precipitation. Nehbandan, Tabas and Khor
will have the highest mean radiation in cities and Birjand will receive the lowest
evapotranspiration and radiation and Tabas the highest rates of evapotranspiration.
Conclusion
From the results this can be concluded that BCM2-A1B models in Birjand Boshruyeh, Ferdous,
Nehbandan and Tabas and IPCM4-A1B models in Ghaen have the lowest differences imulated
values with observed values. Results of LARS model simulations for the next fifty years
showed an average low temperature in Ghaen and Birjand cities. The Birjand has the lowest
rates of evapotranspiration and Tabas the highest temperature and the least amount of
precipitation. Ghaen had not seen much rain, but relative to other stations it will have weak
increasing trend. The results of analysis of Makesens, Sin’s Estimator and Mann-Kendall
showed that in the years from 2011 to 2060 we will experience an increase in the minimum
temperature, maximum temperature and evapotranspiration in all the stations and also a
decrease in all (except Ghaen station). It will also observe an increasing trend in radiation in all
stations except for Ghaen and Ferdous.