فصلنامه فضای جغرافیایی
پیاپی 15 (بهار و تابستان 1385)

City and urbanization are features that have taken a new form after industrial revolution and attracted different experts from diverse sciences. Today urban regional network within the worldwide urban grouping or the urbanization of the world and globalization have formed within new concepts entitled network society or spatial society. The study of them will alleviate the missed chains and the real recognition of the system and worldwide urban network.

Climate and its related parameters such as precipitation, temperature, moisture, and so on, and also their probable changes during a certain period play a major role in human living environment. Therefore, through the recognition of these elements and the relevant changes using quantitative and statistical models, there will be provided the possibility of sustainable utility of the nature.In the existing study, we have used the precipitation records of synoptic stations of Iran for a long term period, after retrieving the data and applying homogeneity tests. Using the SIAP equation, we have drawn zoning map of Iran based on standardized values and the coefficient of variation of precipitation have been studied and finally the coefficients of variation map of Iran has been prepared. According to the results obtained, in the years 1966 and 1973 all over Iran has experienced droughts and since 1995 until 2001 a very long desiccation in most parts of Iran has dominated. Also the studies indicate that the relationship between height and precipitation in Iran has a high rate of uniformity and the study should be carried out in a regional basis, because there is no correlation between precipitation and height in some parts of Iran. For example, the Caspian Sea shores experience higher amounts of precipitation despite their lower elevation, and can be regarded as one of the precipitation poles of Iran. The reason is that the rainfalls in Caspian shorelines are generally derived from convective and dynamic rising rather than orography. The effective factor in Iran's precipitation in winters is the emergence of western air masses and the existence of subtropical Azure high pressure, and in summer the dominance of dry periods.

This article is concerned with studying the introspective and environmental potentials of coastal cities of Iran with an emphasis on Bandar Torkman and is pursuing the answer for the main question of "what are the potentials of coastal cities and what is the position of Bandar Torkman in this regard?" For doing so along with the reference to the offices and libraries and gathering the relevant information, we followed the analysis of the findings, and came up with conclusion of: the coastal cities mainly include three main implications of fishing, tourism, beach activities. If they are taken into appropriate consideration, these cities will contain an excellent potential for regional development. Bandar Torkman possesses only one of these three activities, namely, fishing and unfortunately, there is a general malfunction and instability in other areas, which needs a comprehensive consideration.

Slope rupture in the area of study that is caused in different forms and appeared on various slopes mainly due to different factors, in addition to resulting in direct death tolls and financial losses, increases the amount of sediments entering rivers. Taking this concept that such ruptures directly or indirectly are coincided with geomorphic characteristics of the basins, in this article, we have analysed the amounts of sediments resulting from slope ruptures in relation to these specifications, using experimental approaches and taking into consideration various parameters such as the area of basins, the curvature of slopes, have been calculated. Applying the results, we have specified those sections that are more susceptible to the slope failures and providing more slope materials to the rivers. The results of the analyses being carried out indicate that different sections of the area have different potentials of failure, and the southern and south eastern areas are completely different from each other. The different sections and the slopes composed of old unconsolidated alluviums and show higher rates of susceptibility to water erosion, and they provide each year considerable amounts of sediments into the rivers.

The predications show that Iranian urban population will triple within 30 years. Therefore, there will be a need for cities containing the present levels of accessories. Although the vertical growth of cities due to the lack of technical facilities and construction techniques, could eliminate the subject of tripling of the cities in a great extent, in order to prevent problems that would be encountered in megalopolises, the necessity for the construction of new cities will be felt.Esfahan is one of the largest cities of Iran that is facing with the limitations on continuous expansion and excess population. The expansion of this city is based on the policy of gradual and continuous growth (after the approval of its Comprehensive Plan in 1971 and its implementation), caused the reinforcement of the idea of making new cities in order to concentrate on discontinuous growth and the reconciling of excess population. Thus, 4 cities were constructed nearby main centers of the region. Now the question is that after 3 decades of these new cities, have they been able to fulfill the urban requirements?The aim of this article is to show the role of new cities in the formation of spatial balances, employment, self-sufficiency, and absorption of some the population and finally, the study of the success levels of new cities.

The area of Pesikhanrood drainage basin in Guilan Province is about 735 Km2. and Shaft is a township consisting of rural system. This region has been experiencing floods since the past and almost every year the floods occur due to the over-saturation of the rivers. These cause problems in human and environmental points of view for the residents. Social and human problems show close relationship with the occurrence of the floods and their impacts. Therefore, in this research we have emphasized the conditions and impacts and the appropriate strategies. In this regard we have carried out field and library studies to recognize the geographic situation as well as the problems floods might cause for the livestock, agricultural lands, the service establishments, and the roads.

We have used daily records of precipitation in six stations of Ahar, Tabriz, Jolfa, Sarab, Maragheh, and Mianeh in order to study the spatio-temporal distribution and the beginning and ending of precipitation. The study and its calculations carried out indicated that along with the increase of latitude in the area, the precipitation commences earlier in fall and ends up lately in spring. In order to recognize the possible differences in times of beginning and ending of the precipitation in various years, we have converted the precipitation data of each station into a standard Z score, and accompanied with the differentiation of the years into three groups of dry, wet, and normal, it was specified that the earliest mean date of beginning of rainfall in all selected stations had occurred in wet years, and the latest mean date for it had been in dry years. Also the latest average for the ending process in all stations has been in dry years.