GEOGRAPHICAL RESEARCH
Year:2011 | Volume:26 | Issue:1 (100)|Papers Count:8

To identify temporal and spatial precipitation models in the southern coasts of Caspian Sea, principle component analysis (PCA) and clustering analysis (CA) were used. In this study, using daily precipitation data, measure of central tendency, statistical dispersion and percentages of three variables of duration, amount and intensity of precipitation events in 46 synoptic, climatic and rain gauge stations from 1957 to 2004 were calculated. Southern coasts of Caspian Sea were regionalized on the basis of standardized data of the 3 variables and its regimes were calculated. Precipitation events of each station was divided into four groups including light, moderate, heavy and super heavy and its regimes were explained. The results showed that there are six monotonous precipitation regions in this area as the spatial variations are more in central parts than east and west parts. The mean of rain duration, variance of precipitation duration and precipitation amount as well as skewness and kurtosis of precipitation amount and intensity are more in central and western parts than eastern and mountainous areas. Despite the fact that precipitation mean is maximum from September to December in different regions but its frequency is different. Frequency regimes analysis showed that coastal areas (regions of 1, 2 and 3), mountainous area in west of Guilan Province (part of region of 3) has maximum frequency from September to December. The mountainous areas in center of Mazandaran province (region of 4) as well as the other regions in mountainous areas (region of 5) have the highest frequency of precipitation events from April to August and in winter respectively. Also, the results show that July and summer have minimum frequency of events in all precipitation groups. The light, moderate and heavy precipitation events have maximum frequency events in March and winter as well as the super heavy precipitation events has the highest frequency in October and autumn.

methods are important for understanding the complex identity of cities and the prediction of their future. Today majority of planners and urban planning authorities believe that the use of these methods can help us to better understand urban systems and predict their behavior. In this regard the Holdren Model is one the quantitative models in the analysis of the urban land use which is applied for specifying the urban sprawl in cities. Therefore, in this paper we attempt to study the urban sprawl of Tabriz on its spatial extent during the years 1335-85 (1956-2006) using this model and the statistical analysis. Results of the analysis and study of Tabriz metropolis during the last half of the century indicate that this city has been facing internal urban sprawl. Open spaces and especially the green spaces, the gardens and fields surrounding it, are more interfered with other land uses altogether ending to destruction of the city structures. There is rapid population expansion and rapid construction of building. Thereby, urban planning projects not reflecting ever changing social economical and environmental situations leads to some sort of urban sprawl. Such shape of the extension is a pattern of an ill city that has lost its spatio-physical characteristics.

In order to determine the snowfall threshold temperature in different regions of Kurdistan province, first the occurrence times of the non shower snow, associated with dry-bulb temperature and dew point temperature at the time of observation were extracted for 7 synoptic stations of the province. Then, the frequency, relative frequency and cumulative frequency of snowfall in different temperature ranges were recognized for each station. Throughout frequency analysis, the normal distribution is recognized as the best probability distribution for fitting to temperature data. According to that, the snowfall probability in a certain temperature and less than that was calculated. In order to predict the type of precipitation, the correlation between dew point and deficit during the falling of snow was determined. The results show that the mean temperatures at the snowfall times are negative for most stations. Due to temperature transition from positive phase to negative, the snowfall frequency in 0-0.5oC is more than the other ranges. Snowfall is rare in temperatures greater than 3oC over those stations. Maximum probability of snowfall with positive temperatures is almost %25 for 0.3oC up to 1oC

Yasuj is one the cities of the country that has had a heavy growth in recent years. The main objective of this study is t help develop improved urban services using inefficiencies of the current services. The important issue in planning urban infrastructures in estimating infrastructures based on population forecast, which is the focus of this study. The research method used in this study was a combination of analytical descriptive, historical and filed studies. In this study due to the types of variables (X2) and Pierson’s correlation coefficient formulas have been used. Findings show that based on its physical development and the overpopulation, Yasuj has suffered from deficiencies in offering urban services. The result of physical development and population growth has been the deviation from the usual standard of infrastructures. Finally, some guidelines are provided to provide to solve these inefficiencies.

Drought is one of the natural disasters that causes a lot of damages each year. This phenomenon is a result of severe and repeated spatial-temporal anomalies in atmosphere circulation patterns. Thus, studying and identifying the synoptic patterns of this phenomenon is inevitably necessary. In this study, first yearly rainfalls in selected stations of the Uremia Lake Basin were temporally standardized. Before defining the spatial-temporal treatment of rainfall, 1999 was selected as the most severe drought in the area. Then, level 500 HP height data located in a scope of 0 to 70o northern latitude and 10 to 70o eastern longitude was formulated as an S-mode matrix for non-raining days. Consequently, in order to identify and classify the synoptic patterns of drought, the statistical method of Component Analysis and Clustering were used. Finally, the composite map of each cluster was prepared and analyzed synoptically. The findings show that at the time of the most severe drought over the catchments area four synoptic patterns prevail, so that after the humidity period in the middle levels of the atmosphere, a quite deep ridge will be settled in the area and consequently a quite powerful high pressure tripped will be prevailed over the land area. These conditions result in stable weather and no rainfall and finally causing the most severe drought in the area.

One fundamental characteristic of "democratic" systems is participation of society in the selection process of political elites that with their direct or indirect selection control and influence national decisions and government’s performance. In Iran, after the Constitutional Revolution, people have controlled state decisions through selecting representatives of Parliament and have influenced the voting procedure and in this process parties have more or less been able to play a role. This paper aims to investigate the relationship between the development level of provinces and provincial parties’ votes using available statistics through a case study on the eight election of Islamic Consultive Assembly (Majlis). The research findings indicate that only in developed provinces, parties act perfectly and effective factors in selecting representatives of many provinces of Iran are ideological, religious, ethnic and tribal characteristics.

Localization of underground dams was carried out at Garmab seasonal river basin at Golestan research station. This project aims to localize and investigate places for establishing subsurface dam in order to control and store underground stream water for the station and study purposes. The methodology was based on studying documents and field research sampling, drilling and analyzing necessary specimen. The area of seasonal river basin is about 1152 Hc and is located on the southwest of Mashhad on metamorphic basement rocks. Investigating rocky outcrops shows the existence of impermeable basement cased over it under flowing water and the main cases of outgoing from springs on the end Garmab basin. Site location was carried out based on the amount of subsurface water and appropriate places for natural reservoirs along the main river and based on basement rock characteristics, water amount, river hydraulic gradient, volume alluvial and effective porosity. Results show that there are three sand storage situations along the main river. These places were further studied and were suggested based on significance and ranking, so that controllable water capacity and catchment reservoir in sites I, II, III were calculated to be about 147000, 158400, 196000 m3 per/years. Control, storage and managing water supply could remove lag of water from area.

Publishing geographical journals which is most often carried out by universities and research institutions and by the private sector in the country has an important role in providing scientific achievements and shows the status of the geographical society of the country. It is also one the evaluation tools for the status of articles, authors and how they are being indexed in the citation databases. This study aims to assess the status of Geographical Research Quarterly on the eve of releasing the 100th issue of the journal. The study is descriptive - comparative which is based on investigating the numbers 1 to 100 of articles published in the Journal during 1986-2011. The study was conducted on 812 articles published during this time in the journal. The results indicate that, the average number of articles published in an issue has been 8.7 and it has a decreasing trend. From 812 articles published in the journal 94.2% were written and 5.8% were translated, recently the publication of translated articles has reached zero. In terms of subject, 48.9% of articles were related to Human Geography, 40% to physiography and 11.1% of articles has marginal titles and topics. In terms of author participation, 65.5% of the published articles had one author, 24.4% two authors and 10.1% had more than two. It should be noted that in recent years the percentage of articles with more than one author has been increasing. In terms of index position in the citation databases based on statistics released by the Islamic World Science Citation Center (ISC), Geographical Research Quarterly has been the most successful geographical journals of the country in 2006 and 2007 considering the citation and impact factor.