فصلنامه مطالعات جغرافیایی مناطق خشک
پیاپی 3 (بهار 1390)

This article tries to evaluate and analyze the quality of social capital as dependent variable in relation to city size as independent variable. For this purpose، using deductive method of reasoning and by appropriate theories of research and methodological framework، we have evaluated the components making dimensions and types of social capital regarding different city sizes at small، medium and great scales in city system of east Azerbaijan. The results of this research reveal that there is a relationship between type of social capital and type of city size. Inverse expansion has occurred in bridging social capital، with increase in city size.

There are some Geomorphologic evidences of climate changes as alternate dry and wet climate in central parts of Iran. Maharloo Lake is a location that has protected the mentioned evidences as surfaces of detrital and evaporating sediments. The Lake drains an area of 4266 km2 and its present- day climate is dry so that evaporation is more than precipitation. Its climatic and lithological conditions have resulted in the evolution of lake as a playa. In other words، flood plains and low traces around the lake indicate the wet climate. The purpose of this research is to detect the changes of the lake area. Topographic map at a scale of 1:25000، Aster Digital Elevation Model، ETM+ and IRSP6 satellite images، Geological map at a scale of 1:100000 and field research were used in this study. Principal Component Analysis and Optimum Index Factor (OIF) techniques were done to detect the area around the lake، and the results were assessed with field works and sampling. The Results of this study showed that the lake has been received more rainfall during the cold last glacial period and that its area was about 517. 6 km2. Due to the presence of evaporation mineral such as Calcite، gypsum and Halite in the rocks of the basin، and due to the decrease of rainfall and increase of evaporation because of climate change، the lake became smaller and evaporating minerals were deposited based on their own solubility، and then calcite، gypsum and salt zones were formed around the lake and consequently Maharloo lake was evolved as a Playa. The presence of Halite in others zones represents that climate change after the first dry period has resulted in the change only in salt zone، but not in the stopping of playa development.

Iran is located in dry zone of mid-latitude in which the mean rainfall is 250 mm and it has dramatic tempo-spatial changes. Rainfalls with short persistency are of characteristics of dry regions and it is also tangible in Iran. However، Iran’s rainfalls persistency ranges from 1 to 45 days and have dramatic tempo-spatial changes، but the maximum amount and days of rainfalls are supplied by rainfalls with short persistency. So، the phenomenon of rainfalls with long persistency is considered as an extreme event which has extreme variability. With regard to the importance of rainfall، especially in supplying Iran’s water resources، the investigation of the role of different rainfall persistence''s in supplying such resources is necessary. Therefore، understanding the fact that each case of persistency of rainfall produces which share of Iran’s rain days and rainfalls as a whole is necessary. To investigate the spatial patterns of Importance of Iranian Rainfall Persistency، a rainfall database with time-place order has been used. In this database، daily rainfall observations exist from 1961/3/20 till 2004/12/30 with 15-kilometer distances on the 7187 cells. First، different persistence''s، rainfall amounts and raining days in the time series of every cell were evaluated and in addition to that، different persistence''s share in the supply of rainfall days and rainfall amount of each cell were also calculated. The proportion of these two estimates gives the importance of rainfall persistency in various regions of Iran. Results showed that Importance of Iranian Rainfall Persistence''s have various spatial patterns. The cases of rainfall persistence from 1 day till 7 days exist approximately in all parts of Iran and larger cases of rainfall persistence are only present in some parts of Iran. The share of rainfall persistency sharply reduced with the increase of raining length. In contrast، Increasing length of persistency does not reduce raining in all parts of Iran. One-day cases of rainfall persistency have the greatest role in the formation of raining days and the production of Iran’s rainfalls whose role is tangible in Central، Western and Southwestern parts (mid-east). In contrast، increasing length of persistency of the rains، rain days and rainfall reduced with different spatial patterns. As the persistency of precipitations increases، the share of precipitation in the Central and Southwestern Iran decrease severely، but in Western and Northern Iran، vice versa is the case. In some of high precipitation regions of Iran’s Western and Northern half، the decrease of rainfall persistency is together with the decrease of the share of precipitation supply and in other regions (high precipitation regions)، and the decrease of the share of precipitation supply is gradual. Therefore، it is a various spatial patterns of share of the supply of rainfall and rainy days by means of different rainfall persistence''s that implies the various spatial patterns of Importance of Iranian Rainfall Persistency. The importance of one-day rainfalls did not show any specific spatial pattern. Therefore، most of the precipitation of persistency is considered the least important of them. The greater the length of persistency rainfall، most of them is important and creates different spatial patterns. The importance of short persistence''s (1 to 3 days) in the eastern half and long persistence''s (more than six days) in the western half of Iran is maximum.

This study، with the help of minimum temperature data، has addressed the prediction of frost during 21 years period by means of neural network in Kermanshah province. In order to forecast frost، data were converted to the values between 0 and 1 by means of a subjective and one to one (injective) function. We have used feed-forward neural network by one hidden interior layer with number of changeable neurons for each station to forecast and ultimately to determine frost spans. The algorithm in this investigation has used back propagation with batch training method and training functions such as Satlins، logsig and Satlin. Determination of frost and non- frost spans in each synoptic station and forecasting Precocious and serotinous frost are results of this study، and the designed network has had a convergence between 72. 22 to 80. 55 percent for each station. Results of this study reveal that، in spite of data limitations، MLP neural network has adequate ability in forecasting and estimating frost.

Geomorphological Landforms and processes are of the most significant parameters that affect the distribution and quality of construction materials especially aggregates. The purpose of this research is to evaluate the effect of geomorphological landforms and processes in the formation and quality of construction materials with emphasis on aggregates in Qalehshahin catchment. Qalehshahin catchment with a drainage area of 169. 8 km² is an upstream subcatchment of Alvand basin in Kermanshah province، and is part of Folded Zagros structural zone. To achieve the purpose of this study، Geomorphological landforms and processes were recognized by Quickbird satellite images as well as field works. Result of this study represents that alluvial fans and taluses have large amounts of weathered and crushed rocks and sediments that can be used as construction materials. To determine the quality of aggregates، 14 samples of aggregates in alluvial fans and taluses were obtained and Impact Value test of aggregates has been done based on sieve No. 8. Results of aggregate Impact Value tests show that means of mentioned test in taluses، new alluvial fans and old alluvial fans are 9. 835، 8 and 9. 47 percent respectively that show appropriate quality of all samples of aggregates. This study represents that، in spite of appropriate quality of aggregates of both taluses and alluvial fans، old alluvial fans have aggregates with lower quality because of long term weathering، whereas the quality of aggregates in new alluvial fans، with fresh and less weathered sediments، is rather better. Overall، result of this study reveals that the evaluation of geomorphological forms and processes has an important role in recognizing and determination of quality of construction materials especially aggregates.

In this study، using different station and up level atmospheric data، at first، statistical properties of the heat wave، occurred from 27 June to 27 July 2010، have been studied and then، using Ward cluster analysis، mentioned heat wave were classified to third period from severity point of view. Three classes of Iran heat waves are; intermediate heat wave with 17 members and average maximum temperature equal to 37. 17 ° C، severe heat wave with 5 members and maximum temperature equal to 38. 2° C and Super heat wave with 10 members and average maximum temperature equal to 39. 28 ° C. Spatial distribution of maximum temperature of 2 m above the ground surface showed that the concentration regions of maximum temperature of Iran، from 4 to 13 July 2010، were located in South West and West regions، particularly in Mahshahr، Dezful، Dehloran and Ghasre shirin stations. Super heat wave was selected for synoptic analysis. Preparation and interpretation of synoptic maps demonstrated that the existence of a thermal low pressure system on the Arabian Peninsula and effects of spreading، activity and migration of low pressure system toward Iran have been the main causes of warming and super heat wave transmission in period of 4 to 13 July 2010. Also، evaluation of the intermediate level maps shows the increase in the thickness of the atmosphere in the period of super heat wave occurrence، and shows that the total Middle East region and Iran are under the domination of the sub tropical high pressure. Pattern of Geo-potential height mean composite maps at the time of occurrence of super-hot waves indicates that a high-altitude deployment ridge is on Iran. The height of this ridge at 500 Hp level reaches to 5940 Geo-potential meters. In fact، the mentioned ridge is eddy that، in the way of the North Africa and Arabian Peninsula، the heat has been accumulated in it، and very hot and burning conditions have prevailed. Direction of heat advection and sources of super heat wave as well as temperature advection rates of different days show the advectional types of super heat wave occurred in the summer of 2010. This super heat wave has left severe environmental، Socio-economic and health Effects in Iran.

Carbon sequestration project is a joint initiative of the government of Iran، UNDP and GEF. The site of the project is a part of rangelands in east of southern khorasan that، due to the proximity to Afghanistan border، has been degraded intensively by afghan immigrants. The project purposes have been identified in global، national and local levels that indicate continuous and systematic relations between global warming decreases and rehabilitate rangelands in arid regions، and relation between the method of environmental resources management and participation of local people. In local level، this project has been performed in order to develop participatory viewpoints in rangeland reclamation، in enhancing the power and capacity of Carbon sequestration and in improving the Socio- economic situations of local people. Hence، project is based on mobilization and strengthening of local people as a fundamental tool for the management of rangeland and economic activities. Accordingly، various training for human capital growth، formation of village development groups as social capital، micro credit as financial capital، rural development for local community and assist people as physical capital، and rangeland rehabilitation in the from of natural resources management as environmental capital have performed in this study. This paper، with monitoring and evaluating the socio –economical effects of mentioned project during 3 years from 1385 to 1387، has evaluated the project results in comparison with project objectives. The results represents that the primary objectives of project have been satisfactorily achieved، and project has resulted in the improvements in socio – economical and environmental indexes in site of project performance.