Climatology
Naser Jafarbegloo; Ali Mohammad khorshiddoust; majid rezaei banafsheh; Hashem Rostamzadeh
Abstract
INTRODUCTION
Today, pre-risk awareness has become an integral part of the national development management and planning system in many countries (Civiacumar et al., 2005). Agriculture is inherently sensitive to climatic conditions. The minimum temperature, which has been identified as the most vital ...
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INTRODUCTION
Today, pre-risk awareness has become an integral part of the national development management and planning system in many countries (Civiacumar et al., 2005). Agriculture is inherently sensitive to climatic conditions. The minimum temperature, which has been identified as the most vital determining factor in the distribution of plant species on the planet, can be both a limiting factor and a factor in the spread and species distribution (Rodrigo, 2000: 155). Therefore, in this study, we examined the changes in minimum temperatures in the statistical period (1980-2010) and predicted these changes in the 2050s (2065-2046) in the Northwest of the country using the LARS-WG microscale method and model output. Atmospheric pairings of HadCM3 and MPEH5 were addressed. The prediction of minimum temperature variations to determine the extent of its future changes and considering the necessary measures to minimize the adverse effects of climate change on agricultural products were of great importance. In this regard, general atmospheric circulation models (GCMs) are designed that can simulate climatic parameters.
DATA AND METHODS
In the present study, the output data of two HadCM3 and MPEH5 general circulation models based on two scenarios A2 and B1 were analyzed by LARS-WG statistical method in 21 synoptic stations located in the Northwest of the country. The results were monthly and periodic on the base period (1980-1999) and the 2050s (2046-2065), thereby the minimum temperature was evaluated and analyzed. In assessing the LARS-WG model, the observational and simulation error data were evaluated using MSE, RMSE, MAE and R2, and the model was evaluated for the appropriate region. The results showed that the minimum temperature in the future period will increase compared to the base period in the study area. This increase in air temperature at the study area is based on the HadCM3 and MPEH5 models, on average, 1.9 and 1.7 degrees Celsius to 2065 horizons compared to the base period. The north-eastern part of the northwestern region of Iran will have higher temperatures than the semi-southern regions. In fact, the cooler regions of the high latitudes will face more incremental changes in the amount of minimum temperatures. The results and achievements of this research are important for long-term plans for adaptive measures in the management of fruit gardens, agricultural products and water resources management. In order to calibrate and ensure the accuracy of the LARS-WG microscale model, the model was first implemented for the basic statistical period (1980-2010); then the minimum temperature output and its standard deviation were compared with the observational data of the studied stations, which indicated a small difference between the observed and simulated values and also deviated from their criteria.
RESULTS AND DISCUSSION
The results of evaluation of observational and simulated data by LARS-WG microscale model using RMSE, MSE and MAE error measurement indices for the studied stations indicate that there is a significant difference between the simulated values and the values of the observed observations. There is no critical 0.05 significance levels, and Pearson correlation values between simulated and real data are acceptable at the significance level of 0.01. The obtained results show that the accuracy of the model varies in different stations. In general, the results of error measurement indices indicate that the LARS-WG model is of good accuracy for micro-scaling the parameters under study. In order to better represent and ensure the accuracy of the prediction as well as to investigate the uncertainties in the studied models, the simulated values were compared and observations were made on a long-term average during the base period in the studied stations using comparative graphs. As can be seen, the observed and generated values in the base period at all stations are very close to each other and the LARS-WG model has been successful in simulating the studied parameter. After evaluating the LARS-WG model and ensuring its suitability, the data predicted by the model for two scenarios A2 and B1 using HadCM3 and MPEH5 models and were examined on a monthly and long-term basis. The study of the status of minimum temperature changes of the studied stations in the future period (2065-2056) shows that the minimum temperature is based on both scenarios and in all months and stations compared to the period, the base has increased. Due to the large number of study stations, only stations located in provincial centers of this study are listed.
CONCLUSION
Cold and frost are one of the most significant climatic hazards on fruit trees. This type of climate risk affects different parts every year, especially the cold regions of the northwest of the country. Studies show that in recent years, the rate of economic damage to fruit trees in this region has increased, so in this study, the outlook for changes in minimum temperatures in this region using the LARS-WG statistical microscale model and output two HadCM3 global model and MPEH5 were introduced in the 2050s (2065-2046). For accuracy and precision of the models, error measurement indices and coefficients of determination and correlation were used. The results showed that the LARS-WG model has a good ability to simulate the studied variables in the study area. The results of long-term prediction of the studied models show that the minimum temperature values will increase in all study stations, which is based on HadCM3 and MPEH5 models on average. In the 2050s, and it will be 1.9 and 1.7 respectively, compared to the base period. The results of the studies of Kayo et al. (2016), Sharma et al. (2017), Khalil Aghdam et al. (2012), Qaderzadeh (2015), Sobhani et al. (2015) and Khalili et al. (2015) were confirmed. In general, based on the studied scenarios and models, the minimum temperatures are expected to increase in the study area in the future. By increasing it, the yield of some crops that need cold during the growing and productive period would decrease. It can also reduce snowfall, followed by frost on crops and lack of water in dry seasons. Therefore, due to the fact that following the climate changes, the conditions of the agricultural climatology are also changing, it is necessary for the relevant officials and planners in the agricultural sectors to adopt the necessary strategies to reduce the consequences and adapt to the new climate.
Geomorphology
Nayer Aghabeigi; Abazar Esmali Ouri; Raoof Mostafazadeh; mohammad Golshan
Abstract
Introduction Estimation of the rivers sediment load has high complexity due to effecting different parameters in this aspect. Regarding the power relationship between discharge data and suspended sediment load use of sediment rating curves is one of the most common methods for determining the sediment ...
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Introduction Estimation of the rivers sediment load has high complexity due to effecting different parameters in this aspect. Regarding the power relationship between discharge data and suspended sediment load use of sediment rating curves is one of the most common methods for determining the sediment yield in ungauged watersheds. Sediment condition shows the upstream characters and using of the obtained data makes a relation between erosion and sediment load. The different parameters such as climate, land use, data accuracy and the applied methods have the effect on the sediment rating curve shape. Agriculture activities such as tillage in the direction of slope lead to accelerated erosion in the watersheds, especially in the Mediterranean area. These decades many studies assessing the effects of climate changes in the future period and it affects on runoff. In this study, the main objective is to obtain sediment changes during the future decade (2011-2030) using the curve rating in sediment estimating. For this purpose, the IHACRES hydrologic model and the LARS_WG climate model were used. Material and Methode The IHACRES model for seven hydrometric stations was calibrated and validated. This model is a rainfall and runoff erosion that require a little data for running including minimum and maximum temperature, rainfall, discharge and study are. This model defined as a lumped model and highly common in watersheds with scarce data. With running this model in all of the models the model parameters were calibrated. Also, the LARS_WG model was used for determining the weather changes that are occurring in the Samian watershed. This watershed has near to 4 thousand square kilometers that have many sub-watersheds. In this study, the watersheds in the west of the Samian watershed were selected for modeling. The average of rainfall in this area is between 220 and 457 mm, and the weather temperature changes in this region are high and that is between -32 to 34 C°. The results of LARS_WG showed the weather changes in each part of the hydrological model inputs that these changes were applied to the IHACRES model and the discharge flow rate was estimated for the future. On the other hand, using the observed discharge and sediment yield were calculated the sediment curve rate. By changes in flow discharge at the study stations, were calculated the suspended sediment discharges for the future period. results and discussion The results of the LARS_WG model showed that the amount of precipitation decreased to 3.68 percent and the minimum and the maximum temperature increased by 16.48 and 5.39 percent, respectively. Decreasing of the input precipitation in most part of the world particularly in Iran watersheds mentioned in many studies. One of the other the most important effect of the climate change in this area is minimum and maximum temperature increase that leads to evapotranspiration increasing and soil moisture loss. The results of the IHACRES model showed that this model has the suitable capability for simulation runoff in the study area, therefore, it was used for estimating the future runoff regarding climate changes. The model output showed that during the next decades the average flow rate in the hydrometric stations will decrease by a total of 16 percent and the number of peak flood events will increase, that the highest increase between the study watersheds observed in the Yamchi hydrometric station with a mean of 2.09 m3s-1 and 16 peak events with over 6 m3s-1. Using the obtained results of the climatic model, hydrological model and the sediment rating curve the suspend sediment changes were estimated for the future period. The result shows that these climatic changes will lead to a 47 percent reduction in the average of suspended sediment load at study stations. Conclusion The consequences of the climate changes have the significant effect on water resources quality and quantity. The aims of this study were calculating the weather changes and it's ruling on discharge and sediment yield changed. the results of this study indicate the effect of climate change on the Ardabil province watersheds is remarkable. Considering the environmental impacts of climate change and dependence on human life on the environment it is necessary to implement an appropriate approach for decent management in Watersheds.
Climatology
Nayer Aghabeigi; Abazar Esmali Ouri; Raoof Mostafazadeh; mohammad Golshan
Abstract
Introduction Estimation of the rivers sediment load has high complexity due to effecting different parameters in this aspect. Regarding the power relationship between discharge data and suspended sediment load use of sediment rating curves is one of the most common methods for determining the sediment ...
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Introduction Estimation of the rivers sediment load has high complexity due to effecting different parameters in this aspect. Regarding the power relationship between discharge data and suspended sediment load use of sediment rating curves is one of the most common methods for determining the sediment yield in ungauged watersheds. Sediment condition shows the upstream characters and using the obtained data makes a relationship between erosion and sediment load. The different parameters such as climate, land use, data accuracy, and the applied methods have an effect on the sediment rating curve shape. Agriculture activities such as tillage in the direction of slope lead to accelerated erosion in the watersheds, especially in the Mediterranean area. These decades many studies assessing the effects of climate changes in the future period and it affects runoff. In this study, the main objective is to obtain sediment changes during the future decade (2011-2030) using the curve rating in sediment estimating. For this purpose, the IHACRES hydrologic model and the LARS_WG climate model were used. Material and Methode The IHACRES model for seven hydrometric stations was calibrated and validated. This model is rainfall and runoff erosion that require a little data for running including minimum and maximum temperature, rainfall, discharge and study are. This model defined as a lumped model and highly common in watersheds with scarce data. With running this model in all of the models the model parameters were calibrated. Also, the LARS_WG model was used for determining the weather changes that are occurring in the Samian watershed. This watershed has near to 4 thousand square kilometers that have many sub-watersheds. In this study, the watersheds in the west of the Samian watershed were selected for modeling. The average of rainfall in this area is between 220 and 457 mm, and the weather temperature changes in this region are high and that is between -32 to 34 C°. The results of LARS_WG showed the weather changes in each part of the hydrological model inputs that these changes were applied to the IHACRES model and the discharge flow rate was estimated for the future. On the other hand, using the observed discharge and sediment yield were calculated the sediment curve rate. By changes in flow discharge at the study stations, were calculated the suspended sediment discharges for the future period. results and discussion The results of the LARS_WG model showed that the amount of precipitation decreased to 3.68 percent and the minimum and the maximum temperature increased by 16.48 and 5.39 percent, respectively. Decreasing the input precipitation in most parts of the world particularly in Iran watersheds mentioned in many studies. One of the other the most important effect of climate change in this area is minimum and maximum temperature increase that leads to evapotranspiration increasing and soil moisture loss. The results of the IHACRES model showed that this model has a suitable capability for simulation runoff in the study area, therefore, it was used for estimating the future runoff regarding climate changes. The model output showed that during the next decades the average flow rate in the hydrometric stations will decrease by a total of 16 percent and the number of peak flood events will increase, that the highest increase between the study watersheds observed in the Yamchi hydrometric station with a mean of 2.09 m3s-1 and 16 peak events with over 6 m3s-1. Using the obtained results of the climatic model, hydrological model and the sediment rating curve the suspend sediment changes were estimated for the future period. The result shows that these climatic changes will lead to a 47 percent reduction in the average suspended sediment load at study stations. Conclusion The consequences of climate change have a significant effect on water resources quality and quantity. The aims of this study were to calculate the weather changes and it's ruling on discharge and sediment yield changed. the results of this study indicate the effect of climate change on the Ardabil province watersheds is remarkable. Considering the environmental impacts of climate change and dependence on human life on the environment it is necessary to implement an appropriate approach for decent management in Watersheds. Keywords: Rating curve, climate change, LARS-WG, discharge, IHACRES.
Climatology
Saeed jahanbakhsh; yagob din pazhoh; mohammad hossein aalinejhad
Volume 23, Issue 67 , April 2019, , Pages 91-107
Abstract
According to the importance of snowfall in supplying water of different regions especially mountainous areas, accurate estimation of snow water equvallent and changes of its coverage would be effective in agriculture, energy, management of reservoir and flood warnings. In this study runoff orginated ...
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According to the importance of snowfall in supplying water of different regions especially mountainous areas, accurate estimation of snow water equvallent and changes of its coverage would be effective in agriculture, energy, management of reservoir and flood warnings. In this study runoff orginated from snow melting in ShahrChay basin under the terms of climate change calculated. For this purpose, snow cover for water year of 2012-2013 were extracted in ENVI software by using daily images of Modis satellite.Then, GIS software the physiographic specification of the basin was obtained. In the next step, data of snow cover, meteorological variables and other necessary parameters to SRM model provided as an input of model and run_off from snow melt was simulated. Then output of the 6 models of atmospheric general circulation with title of 3 scenarios nomely A1B , A2 and B1 converted to a downscaleing by using LARS-WG model. By comparing the output of 6 models in the future period to period based on monthly statistical, the best model and scenario for generation of air temperature and precipitation data in the period 2030-2011 were selected. As a result the HADCM3 model under the scenario A1B was used for generation of precipitation and the MPEH5 under scenarios A2 was used for generation of temperature data. In order to estimate the rate of change of runoff orginated from snowmelt rate of change of monthly data of air temperature and precipitation of the base time period as well as future time period under selected model and scenarios was entered to SRM model in simulation time period. Results for all of the scenarios show that runoff orginated from snowmelt in late spring will be reduced. The peak flow appeared earlier in comparison with base time period and its value would be larger than base time period.
Climatology
mostafa karimi ahmad abad; Adel Nabizadeh
Volume 22, Issue 65 , November 2018, , Pages 265-285
Abstract
Now days ,in order to providing the best mecanisms to damp the impact of climate change , climatology scientists need long term prediction of climatical variables and their changes. This research studies the impacts of climate changes on daily parameters such as: rainfall , min and max temperature and ...
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Now days ,in order to providing the best mecanisms to damp the impact of climate change , climatology scientists need long term prediction of climatical variables and their changes. This research studies the impacts of climate changes on daily parameters such as: rainfall , min and max temperature and sunshine hours in Urmia lake basin. (Tabriz ,saqqez and Urmia synoptic stations) , selected as study stations , have long term gaged data for mitigation and Adabtation from 1980 to 2009. data prediction under as scenario A2 a type of GCM as HADCM3 model was used to simulate climatic parameters in 2011 to 2040 by LARS-WG model downscaled. Results show that prediction time distribution has been limited to short time in comparison to past decades .In other words the number fraindy days has been diminished , as far as in the future April will have the most decrease (7.5%) and February will have the increase (5.8%) in precipitation . overall , the precipitation max and min averay temperature of basin will increase about (4.3%) , (1.35 ) and (0.64 ) respectively in addition, November will have the most increase in daily max temperature (12.7) and January will have the least increase (0.33) in this parameter the sunshine hours of basin will not increase significantly .
Climatology
asadollah khoorani; zahra jamali
Abstract
The aim of this paper is assessment and comparison of potential impacts of climate change on drought indices in an arid and a semiarid station. For this purpose, daily data of minimum and maximum temperature, sunshine and precipitation are used. This data were downscaled statistically by using ...
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The aim of this paper is assessment and comparison of potential impacts of climate change on drought indices in an arid and a semiarid station. For this purpose, daily data of minimum and maximum temperature, sunshine and precipitation are used. This data were downscaled statistically by using LARS-WG model based on A2, B1 and A1B scenarios. These climatic parameters are projected for 2011-2040, and RDI index was extracted for both observed (1961-1990) and projected data from HADCM3 model. The research outcomes show drought severity has increased under each scenario in both stations, except for Shahrekord under B1 scenario. For Bandarabbbas station, percent of droughts are about 6.7, 10 and 10 under A1B, A2 and B1 scenarios respectively. This parameter is 6.7 and 3.3 percent under A1B and A2 in Shahrekord station and the number (percent) of droughts will decrease about %10 under B1 scenario in this station.
Climatology
nader pir moradian; hossein hadinia; afshin Ashrafzadeh
Abstract
Abstract Prediction and evaluation of meteorological data in effect of climate change is very important especially in water resources management. LARS is a model that generates weather data and predicts weather parameters by downscaling global circulation models (GCM). In this study, in order to evaluate ...
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Abstract Prediction and evaluation of meteorological data in effect of climate change is very important especially in water resources management. LARS is a model that generates weather data and predicts weather parameters by downscaling global circulation models (GCM). In this study, in order to evaluate 15 GCM models performance in simulating the minimum and maximum temperature, radiation and precipitation in Rasht synoptic station (2011-2012), statistical downscaling of each model was performed by LARS model. Then, the mentioned data were predicted on the basis selected GCM models for 2013-2042 and 2043-2072 periods. The results showed that the highest increase in annual average of minimum and maximum temperature will occur during the 2043-2072 periods with 1.3 and 2.0 °C, under A2 scenario, respectively. The amounts of radiation will decrease in future periods for all seasons. The highest decrease (143.4 MJ m-2) of radiation will occur in 2013-2042periods in winter under A2 scenario. The seasonal precipitation will often increase in future periods. The highest increase of seasonal precipitation (55.5 mm) will occur under B1 scenario in 2043-2072 periods for autumn.
Jahantab Khosrovanian; Majid Onagh; Masud Guderzi; Seyyedasadollah Hejazi
Volume 19, Issue 53 , September 2015, , Pages 93-115
Abstract
Abstract
A stochastic weather generator can serve as a computationally inexpensive tool to produce multiple-year climate change scenarios at the daily time scale which could incorporate changes both in mean climate and in climate variability as well. In this paper, LARS-WG model was used to downscale ...
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Abstract
A stochastic weather generator can serve as a computationally inexpensive tool to produce multiple-year climate change scenarios at the daily time scale which could incorporate changes both in mean climate and in climate variability as well. In this paper, LARS-WG model was used to downscale GCM outputs and then tp assess the performance for generated daily data of precipitation, minimum and maximum temperature and sunshine hours. Study area was Ghare-su basin in Gorgan and the station is called Gorgan synoptic station. The first step was running the model for the 1970-1999 periods. Then mean of observation and synthetic data were compared. T-test was used in the 99% significance level, and the difference between observation and synthetic data was not significant. Finally monthly mean of observation and synthetic data were compared using statistical parameters such as NA, RMSE & MAE. As a final result, it was found that performance of model was appropriate for generating daily above-listed data in Ghare-su basin. Thus, it was possible to predict the climatic parameters from GCM output using LARS-WG model. Also minimum and maximum temperatures had the highest and sunshine hours involved the lowest correlation. After ensuring performance of model to simulate above-mentioned parameters, this model used to predict future trends (in 2011-2030 and 2080-2099) with A2, A1B and B1 scenarios of the HadCM3 model was. Results showed that future temperature would increase 0.56-4.04 degrees centigrade while precipitation would increase 10.28-23.71%.
