فصلنامه مطالعات جغرافیایی مناطق خشک
پیاپی 29 (پاییز 1396)

Urban density includes population density, density of residential areas and employment density In addition, net and gross density are one of the most important determinants of the travel patterns of residents, which can be determined the type and extent of using personal and public transport and consequently the amount of CO2 emission. Kockelman (1997) states that the significance of the compaction index in relation to travel behavior can be as large as the density index as representative, and in the top of the other indicators of the urban form. On the other hand, Ewing and Cervero (2010) studies show that the VMT or VKT is the best indicator for measuring the effect of different types of densities as independent variables on energy consumption in daily trips. And its impact is so high that the per-capita correlation coefficient (VMT) and CO2 emissions are approximately equal to 1, and the per-capita correlation coefficient (VMT) and nitroxid emission are equal to 0.74.
The main goals of this paper are to find out what statistical relations and correlations exist in Mashhad between the main types of urban densities and the per capita of VKT. And which types of density can have the greatest effect on reducing VKT? What is the situation of 15th traffic areas in Mashhad in terms of carbon emission of private vehicles? How much the urban densities can impact on carbon emission reduction? The research method is based on quantitative strategy and descriptive-analytical method. This paper has been used to analyze the behavior of residents' travel and its impact on the emission of pollutants from the dependent variable VKT. Also, the urban densities variables such as population density, employment density and non-residential employment density residential blocks density and land use density, which indicate the intensity of land use, were considered as independent variables.
The data needed to measure VKT was conducted from the results of origin-destination census analysis in Mashhad, 2011. By accessing the results of this survey and measuring the average distance between the origin and destination of private cars in each region, VKT was obtained for each region. The findings show that urban areas with a density of more than 100 hectares of VKT are 2.5 to 4 km less than densities below 100 hectares. By reducing density from the central regions to the margin, the average travel distance increases. In the case of population density variable, the correlation coefficient was -0.557 and P-value = 0.02 which suggests that "there is a significant indirect relationship between increasing the density of regions and reducing the distance of personal car journeys at a significant level of 0.05". In addition to population density, employment density is also very effective in reducing VKT. In addition to population density, employment density is also very effective in reducing VKT and the correlation coefficient was -0.79 (P-value = 0.00) between these two variables at a significant level of 0.01. "
There is also a significant relationship (correlation coefficient = 0.656 and P-value = 0.008), between the density of residential blocks in each region and the vehicle kilometer travel of the residents in each area.
The fourth type of density is the application of mixed land use density .The results of the correlation between this variable and VKT shows that there is a significant relationship between the increase in the diversity of land use and the reduction of VKT. This correlation coefficient for the city of Mashhad is equal to 0.552 (p-value =0.03). Finally, we calculated the amount of carbon released by the each traffic zone and by using the influence coefficients which obtained from the multiple regression equation; we calculated the carbon reduction in the case of increasing density. The highest emissions of carbon contaminants are in areas that are not in a desirable situation of land use intensity. These areas, meanwhile, are more dependent on automobiles In this paper, four types of densities including population density, employment densities, residential block densities, and mix land use density were considered. And finally, it was revealed that although all four types of densities have a linear relationship with the vehicle kilometer traveled (VKTs). However, only 2 variables including non-resident employment density and density of residential blocks are significant in regression model. Also, by calculating the amount of carbon released by the segments of the 15 traffic areas, it was found that the low carbon approach to transportation of the city of Mashhad in the area of urban densities should be emphasized by employment densities, because business trips have a larger share of personal trips than other travel destinations.

In the future decades, climate change will influence the food and water security,and there are substantive evidences indicating that the developing countries will confront extensive pressure from the disastrous consequences of this climate change. The agricultural section is the most vulnerable section to the climate changes due to its dependence on the condition of water resources and changes of temperature. The aim of the present study is to assess the influence of the climate changes on the influential climate indicators for the production of the pastiches in Sabzervar. In this regard, SDSM software has been used for the down scaling of the data of the second generation of canESM2 that has been modeled by the Canadian center of climate change under the new climate change scenarios. In this study, the daily data of meteorological stationincluding the maximum, minimum and average of temperature and the level of rain on the daily basis from 1976-2005 from the Meteorological Organization are obtained. This study has used the effective climate-agricultural parameters on the growth of pastiches which are divided into two indexes of temperature and rain in a general classification. The temperature indicators are both seasonal and annual which the seasonal indexes include the average, maximum and the minimum of the temperature of the growth season, DTR or daily temperature range (maximum and minimum temperature difference) during a month.Additionally, the annual indexes include the number of annual days with a minimumor maximum temperature less than 10thpercent and more than 90percent of the number of the frozen days and the length of the period withoutice. The index of rain include total annual precipitation, total rainfall of growth season, rainfall in different stages of the growth season, the number of the days with more than 95percent(very humid days), the percent of the registered rainfall in very humid days as well as the maximum dry season or DPL. Due to the semi-arid climate of the region and the summer with low level of rainfall, the level of evaporation is calculated by the formula of evaporation and perspiration of the plants. To assess the stages of the climate indexes in different phonological stages, the tests of Man-Kendall (Z) and Steady-axis tiltare used. Also to study the consequences of climate changes on the structure of the effective climate parameters on the production of pastiches the outputs of the model CanESM2 under the scenarios of (RCP2.6, RCP4.5, and RCP8.5) for the period of 2011-2040 are used. The time of the beginning of flowering for pastiches from the period 1976-2005 is from March 20 to the October 27 for six months. The obtained outputs from the used indexes in the research show that the average parameter and the maximum and minimum of the temperature of the growth season have a significant trend. Analysis of the averagerange of daily temperature during the month of cultivation or DTR does not show any significant process. Assessment of the indexes of cold nights and days shows a significantdecrease.This process is incremental for the two indexes of warm nights and days. The results from of annual temperature indexes show that the climate is moving towards warming. Analysis of the parameters of total annual precipitation (250mm), the percentage of the annual precipitation on very humid days (82 percent) and the length of dry period (122days) indicates the dry and low rainfall condition of the region. The result obtained from the sub- scaling data of model Canesm2 under the scenarios of RCP2.6,RCP4.5,RCP8.5 for the period of 2011-2040 showed that the flowering stages ofpastiches in the coming years will start sooner than the base climate. The average indexes of the growth season, the minimum and maximum temperature has increased for all three scenariosthan the base time.The daily range has not changed much due to the increase in both parameters (maximum and minimum). Despite the increase of the temperatureduring the simulation process the number of the warm nights and days does not changedmuch compared to the basic climate. Assessment of the annual indexes of the number of nights and cold days indicates an increase in this index in comparison with the observed period. The frozen days also indicate a slightdecrease of one day for the upcoming period. The ice-free period has increased over the coming years. The average length of the dry period in the decade was increased by 14 days.The results gained from the rate of evaporation shows that in the future the demand for water in all scenarios has risen like the basic course. The climate elements play a crucial role in the growth of the plants and are considered uncontrollable parameters for agriculture. In this research the effects of climate change on the effective temperature and rainfall indexes on the pistachio production was studied in Sabzevar station by using the output model of Canesm2 under the new scenarios of climate change from 2011-2040. The output from the study of the average temperature of the growth season for the base period showed that this parameter has an increasing trend of about 0.6 ° C per decade. The assessment of the effects of climate change on the indices used in the study for the study area showed that the average temperature for RCP2.6, RCP4.5 and RCP8.5 scenarios in the growing season in the range of 0.6 to 0.8 ° C in decades has increased trend This has led to an accelerated flowering and a quicker examination of the product than the observation period.The acceleration of phonology stages is the most important consequence of climate change in agriculture. Studying the consequences of climate change on the applied indexes of this case study showed that the average temperature forRCP2.6, RCP4.5, RCP8.5 during the growth season has increased 6 percent per year. This increase has made the flowering and ripping stage faster than before.The acceleration of phonological processes is the most important consequence of climate change in agriculture. The results obtained from precipitation in all scenarios indicate a decrease in the base time. The water requirement of the product has increased in the coming decades due to rising temperatures and lower rainfall. Therefore, according to the stated content, the water needed for the product should be provided by modifying the cultivation pattern, proper management of water resources and new irrigation methods.

Today participation considers one of the main concepts of sustainable development. One aspect of participation is citizen participation in urban affairs that the people have much more intercommunity in the city affairs that it provides the possibility of further success, as well as makes easy preparation and implementation of urban projects and consequently improves living standards. The purpose of this research is investigation the Indicators of residential participation at 9 region of Tehran in urban affairs. The present paper is categorized as practical aiming, and regarding the data collection is classified as descriptive-scaling. In general, it is structural equation modeling. Using literature review a questionnaire was compiling with eight variables (Social awareness, social interaction, social trust, social solidarity, and active participation, attitude to participation, satisfaction, and place attachment) with fifty seven questions. Statistical society is residents at 9 region of Tehran with 158,425 population that by Cochran formula sample size of 384 is obtained. In order to analyze data SPSS21 and smart- PLS3 software was used. The results show that the variables of social interaction, social solidarity, social trust and social awareness of social capital have a significant impact on attitude to participation. Satisfaction variables have effect the place attachment. Place attachment have a positive influence on active participation and attitude to participation. Generally, subject citizen participation in urban affairs In 9 region at the same time influenced by social features, place and individual.

Zayandeh-Rud basin in central Iran is a region with water problems. Zayandehrood River that originates from the Zardkuh Bakhtiary Mountain is the most important river of the region for the development of agriculture, and a supply for heavy industry and drinking water sectors and is very important in all of economic activities. In the last decade, the water resources of the basin have decreased, so that part of the length of the River in the middle and downstream of the water flow has dried or temporarily turned off, and the allocation of agricultural water to the agricultural lands of these sectors has decreased significantly. In this study, to analyze the effect of natural factors on instability of water resources in the basin, Investigated Changes in climate indicators such as rainfall, Snow ratio to total rainfall and temperature changes in Chelgerd Station in recent decades. Chelgerd Station is the main source of supply of natural river water and its changes directly affect the water volume of the river. Then, the total water resources of the Basin and changes in the volume of water entering the Zayandeh-rud dam were studied and groundwater changes (number of wells and groundwater level) were compared in two periods of 2006 and 2011. The source of the data is the Iran Water Resources Management (Ministry of Energy) and Meteorological Organization. Natural and human factors in the instability of the basin water can be effective. In this research, is studied the role of natural factor including Temperature and Precipitation changes in the occurrence of instability of water resources in Zayandeh-rud Basin. Based on this, is studied climate change of Chelgerd station (Koohrang) as the main source of natural water supply, In the variables of precipitation, temperature and snow ratio to total precipitation, Then its effects on surface water and Groundwater resources have been investigated in recent decades. The research is based on descriptive-analytical and quantitative method. Research data received from relevant departments, such as Meteorological Organization, Iran Water Resources Management Organization (Ministry of Energy) and Regional Water Company of Isfahan, and has been analyzed according to the research objectives. In each stage of the research has been used from Comments of academic experts and organizational experts Comments. In order to analyze the effect of natural factors on the occurrence of instability of water resources in the Basin, based on available statistics, climate change such as rainfall changes during the period of 50 years (1966-2016), the ratio of snowfall to total rainfall during the 45-year period (1971-2016) And temperature variations during the 30-year period (1986-2016) at Chelgerd station. In addition, due to the importance of the temperature of autumn in the melting of snow reserves, seasonal temperature changes were compared to the long-term average at this station. In the water resources section, firstly, the total water resources of the basin and then changes in the reservoir volume of the Zayandeh-rud dam in the last 45 years have been investigated. In the following, changes in groundwater resources were compared on the basis of two inventory periods in 2006 and 2011. Accordingly, investigated changes in the volume of groundwater aquifers, the number of wells and its rate of discharge in two statistical periods compared with the river flow and the occurrence of water resource instability. Checking the precipitation rate of the Chelgerd station during the 50 years period (1966-2016), shows the trend of the rainfall variable and in the last two decades the precipitation has decreased. In the past two decades, two climatic drought has happened, the first drought in the year 1998-2001, the total precipitation of Koohrang reaches 900-1000 mm per year. During the years of 2001 to 2007, the rainfall is relatively improved and the rainfall reaches over 1500 mm per year. Since 2007, rainfall has fallen in Koohrang station and has reached 900 mm per year; since the beginning of the second drought in the Zayandeh-rud basin, precipitation has been between 900-900 mm per year. Investigation of the rainfall ratio in the period (1971-2016) shows that the ratio of snowfall to rain has decreased over time. While already nearly more than half of the rainfall has been in the form of snow, it has rarely reached 50% since 2001, and less than half of the total rainfall in the Chelgerd area has been snow. Temperature variations over the course of 30 years (1986-2016) show that the temperature has increasing trend and by about 1 degree to the temperature in recent years has increased. In addition, the comparison of the temperature of the fall season in year 2017 compared to the previous year’s shows an increase of 23% compared to the previous year and a 53% increase in temperature compared to the long run. Investigating the variation of Basin water resources by Computing the volume of the input of Zayandeh-rud dam that correlates directly with the volume of precipitation in the Basin, shows a decreasing trend and, in accordance with the dry climatic Courses, the volume of water entering the Zayandeh-rud dam decreased and the volume of water has been usually below 1 billion cubic meters. Investigating the variation in the volume of groundwater in the two census periods (1385 and 1390) indicates that more than 9,000 wells were drilled during this period and an average increase of about 5 meters depth of wells and average groundwater level. The results of this study indicate that natural factors and climate change have been effective on the occurrence of instability of water resources in the Basin and reduction of River flow, Due to decreasing rainfall and snow-to-rain ratios as well as increasing the air temperature, Basin water resources and the volume of inlet of Zayandeh-rud dam has decreased. With decreasing River flow during these years, water scarcity has been compensated by digging wells. Increasing the utilization of wells and reducing River water flow has reduced groundwater levels in the Basin. Reducing groundwater levels exacerbates the unstable water condition.

Urban areas are the most important place to the formation of citizen action, agency, possibility and context of social functions. In this sense, space is always the potential that can be actualize in ways such as the presence of people in it. In today's everyday life, public spaces including parks can be as active domains, abandoned citizens  from the routine imperative, or at least pull out them for a short time in the life of the temporal. In this sense- and in this research, space is considered as a representation for individuals that In addition to its spatial differences, in terms of rhythm and flow of time is different from other spaces. In this study anywhere in the text that speaking about space, meaning is "space as a social construct". This means that space just in the physical meaning is not purpose  of research. Because if we understand  space such a one-sided, we can not conceptualize and formulate the presence as a constructive factor in connection with that space we studied. This study with utilizes qualitative research methodology, tries to identify affecting indices to preferences of people's presence through interviews with the groups in space and then analyze them through content analysis, It is notable that during the field interview at least  in 39 people have been reached theoretical saturation. Finally, after identifying 21 indicators, including spatial rhythm, features of keeping, Spatial awareness and the action-oriented presence and features of invisiblity. Has been analyzed them and how their influence has been on the presence of people in the park. After analyzing solutions to strengthen presence of people in the park has been proposed.

Drought is a climatic phenomenon that begins slowly and has a hidden nature. The duration of its occurrence and the resulting damage occur gradually in different sectors. Therefore, assessment and investigation of drought is very important in planning and implementation of actions to cope with drought. Droughts are divided into different types. One of the common methods of drought assessment is the use of drought indices which everyone can describes a type of droughts. In recent years, the use of Composite Drought Index (CDI) have attracted the attention of researchers. In this study, a new Composite Drought Index was developed that combined the three components, including the Groundwater Resource Drought Index (GRI), the Modified Standardized Precipitation Index (SPImod) and the potential evapotranspiration (ETP). In the next stage, the drought condition of Shahrekord plain located in Chaharmahal and Bakhtiari province was assessed in a 31-year period (1985-2015) using the Composite Drought Index (CDI). The results showed that the Shahrekord Plain was frequently experienced some wet conditions during the years 1985 to 2000, but it has suffered from consecutive severe droughts from 2008. In general it can be said that the developed CDI index is well able to describe the composite behavior of meteorological and groundwater droughts in the study area and is recommended as a new index for monitoring and assessing regional drought.

The aim of this study was recognizing Semantic understanding of villagers from the impact of dam in Roodbar region. This research was carried out using qualitative method and Grounded theory. In this method, the theory is based on data. The construction of the dam in the studied area has had different dimensions and consequences and since dewatering, it has had a great impact on the lives of villagers. After building the dam in the study area, the villagers had different reactions. Some migrated and the other group chose to resist and stay in the village. After an interview with twenty villagers, the process of coding and extracting categories was carried out. Categories were extracted in the form of environmental problems, Economic slowdown and livelihood, reduced public services, Lack of proper planning, ambiguous future, immigration problems, Reducing social solidarity, eliminating cultural backbone, eroding institutional trust, Social insecurity and dissatisfaction with the situation. Interviewees evaluate the dam construction effects negatively and the feeling of confusion, disappointment, and concern about the status quo is the concepts that indicate the situation of the villagers.