GEOGRAPHICAL RESEARCH
Year:2005 | Volume:19 | Issue:4(75)|Papers Count:11

Estimation of energy needed for heating or cooling buildings during cold or warm season, is one of the most important parameters in architectural designs. This energy is a function of climatic values named heating (HDD) or cooling (CDD) degree-days .In this study, as a first step, a computational model is developed which calculates daily values of HDD and CDD based on mean monthly air temperatures, for a network of 218 stations .In the second step, the spatial distribution of HDD and CDD was analyzed by multiple regression method. Based on the equations obtained, the HDD and CDD at each point of country could be estimated. In the next step, considering some thresholds for HDD, the 7 climatic groups from H1 (Mild) to H7 (Extra cold), were identified. With similar method the regions were divided into 5 groups as function of their cooling degree-days need, from C1(mild) to c5 very warm . In addition, four humidity groups were added to the classification system. As a result the proposed classification, was defined by general formula of HiCjRk where i, j and k (only for costal zones) vary from 1 to 7, 1 to 5 and 1 to 4, respectively. Finally, based on criteria of classification, the climatic classification map of Iran with the 1:1000000 scales at GIS media was provided.

In many areas snow is the dominant source of surface run off. Snow melting usually begins in the spring and if mixed with rainfall in warm season, cause overland flow. Therefore, information about the volume of the fall and melting of snow is very important to foresee the situation of the flow and its volume. Usually in equipped areas, the thickness of snow is measured through the use of standard snow boards and snow stakes; but in unequipped areas usually empirical methods are used for measurement of the thickness.The area under consideration is one of the unequipped areas; therefore empirical methods were used to estimate the cover and volume of snow in the area. The factors used in this investigation are temperature and rainfall data for various interval times belonging to 6 stations in and around the area with the length of 20 years data.The results show that the snowfall starts from October with the maximum falls in December and January. While temperature rises melting starts and in Jun there is no snow left in the area. The average of coefficient of snow in the area is from 92.5 percent in January to 0.9 percent in October.

In this research which is based on synoptic Climatology procedures including synoptic maps interpretation and statistical analysis, the air masses influencing Iran, in three stations: Tehran, Shiraz and Kermanshah based on the temperature and dew point, daily upper air data surface, 850,700,500 hecopascal for the years 1981-90 were studied.Also in this research in order to identify the air masses, based on the conservation of air mass properties law, the following parameters: potential temperature, wet bulb potential temperature and mixing ration were selected, and Calculated. statistical analyses such as principal component and cluster analysis were done. Given all the information above the results are as follow:For Tehran station 4 Shiraz 3 and Kermanshah 3 factors were extracted, and based on these factors hierarchical cluster analysis for aggregate days was applied and then mean analysis for all data was done. With comparing the average value of all parameters in each groups and comparing them with the data of Aswan, Ashkhabad and Mediterranean air mass properties, these air masses tmA.,cA,cP,mT,cT and med. were determined.And then based on the data of potential temperature and mixing ratio of 500 hectopascal index days was extracted and tephigrams for these days were prepared and their synoptic maps were studied.

North- East Iran has been proved as a major agricultural pole and ranching center. It enjoys relatively optimum climatic conditions, and roughly falls into semi- humid to semi-dry climatic regions.However, despite its prime environmental and climatic characteristics, it is the scene of very devastating seasonal floods which take many lives and cause considerable damage to property and the environment every year.Thus, identification and evaluation of appropriate patterns resulting in storms and floods require considerable attention in this region. This will definitely, in turn, facilitate resource management. Methodologically speaking, the study is based on long term precipitation data and relevant station discharges during a period of 30 years (1970- 1999). Along with this, daily weather maps of upper as well as surface layers were analyzed.Results show the four following patterns pertaining to flood:1.European migrant low pressures, originating from Scandinavia.2.Mediterranean low pressures.3.Sudani & Red sea low pressures.4.Siberian migrant low pressures which originate from Arctic regions near to northern Siberia.The peak of precipitation is when low pressures prevail in the region. In other words when the region is under the influence of cold fronts.The continuation of rainfalls is associated with prevalence of the Red sea low pressure system along with either the Mediterranean low pressure or European Arctic low pressure simultaneously. This coincidence results in a mixed front per se

Detection of any climatological system’s regularities paves the way for proper analysis and weather forecast. From this point of view synoptic climatology of the Red Sea region is studied from the early researches till now. All these researches can be classified into three periods.In 1940s and 1950s, the initial rainy mechanism and the Sudan monsoon low in the Red Sea region has been considered. In this period the occurrence of rainstorms in the Middle East in the fall has been attributed mainly to intrusions of a low pressure trough extending from the Sudan toward the Red Sea region, then to eastern Mediterranean. This period’s investigators emphasize that the Sudan monsoon low is a dominant feature in the Middle East in October.Elfandy in his investigations, explains that the Sudan monsoon low normally extends to about latitude 15o -19o N, but continue with a small inverted V-shaped arm projecting northwards to the northern Red Sea. He believed that changes and oscillations in the mean position of the Sudan monsoon low are also dynamical.The movement of the Sudan low can be classified into two distinct types of oscillations. The first is displacement of its center from near the Abyssinian (Ethiopia) Plateau and back again twice during the course of the year. The second includes a series of relatively small oscillations superposed on the annual track because of the passage of mid-latitude troughs over the East Mediterranean or Eastern Europe.In 1960s undeniable importance of the Red Sea Convergence Zone on the desert Locust led to exact investigation of local air circulation structure of the region.Investigations of the surface wind distribution along the Red Sea shows that the geographical features of the Red Sea depression are responsible for the strong predominance of winds from NNW and SSE, i.e. parallel to the escarpment along both sides of the depression. While the NNW winds are reflected from the Mediterranean Westerlies and the SSE winds are diverted from the low-level ENE monsoon or trade of the Arabian Sea and the Gulf of Aden. Undoubtedly the position of the Red Sea Convergence Zone varies according to the synoptic situation and to the intensity (and inertia) of both wind systems.By increasing climatic data in recent decades especially from upper troposphere, there are several researches in relation to synoptic patterns from middle and upper troposphere with heavy rainfall over the Red Sea region and Middle East.Related to these studies, formation of initial convergence regions is the result of the relationship between tropospheric flow and topographical Features.As well, evolution and extension of the Red sea region’s low pressures and their displacement to Middle East related to location and intensity of Subtropical jet stream also amplitude and axis orientation of mid-latitudes trough in the east of Egypt.Concerning the subtropical jet stream, in summer it is positioned over Turkey, then too far from the Red Sea, where it may affect the Red Sea trough. From September to October the subtropical jet stream is displaced southwards, where it may initiate the development of a Red Sea trough. Moreover the monthly distribution of the major floods in the southeast Mediterranean shows the Red Sea trough floods are most frequent during October and November.In recent studies it was suggested that the Red sea trough development may take place as a result of a lee-type cyclogenetic process in association with the position of the jet over the area of the west of the northern part of the Red Sea area.

The town of masouleh is located some 60 km away from Rasht (Guilan, Iran) , 30 km southwest of Fooman, in a mountainous and forested area. Its elevation is 1050 m above sea level and it is established on a rocky slope having a unique architecture in Iran and even in the world. The harmony between architecture and natural and geographic environment, is exclusive and astounding and has been documented as a national heritage under the code of 1090. Therefore ,the preservation and conservation of this natural collection is very important both for the present and future. However, at the present time this town is facing with various natural and man-made hazards such as debris falls, floods, mudflows, earthquakes, and human caused problems resulting from development projects. These factors maximize the risk probablity. On the other hand, evidence suggests that the previous location of Masouleh has been 5 km away from the present place, and there do exist the remains of human civilization. Natural disasters have destroyed the old Masouleh. Natural hazards can cause hazards and change likely dangers to disasters. This hazards are: natural climatic conditions, hydrological, geological, biological and technological effects.To identify the Natural hazards of Masouleh, the author has studied and used statistical meteorological, hydrological data in the framework of a research plan at Islamic Azad University (Rasht Branch).This article also makes attempts to present the geographic location of the old city of Masouleh and discover the hazards and risks that threaten people both at present and future.

Knowing and determining the core and peripheral countries in different geographical areas and in the areas under the influence of the regional powers will be considerably helpful in studying the structure of the regional power. In order to know and identify such countries, we need a classification based on the countries’ national power. Through determining the geopolitical level and weight of each of these countries, we can evaluate the levels of their national power. The evaluation of national power of a country, in turn, requires evaluation and consideration of different elements and social, cultural, political, territorial, economic and scientific factors of that country. These are generally indicative of the weight and level of the national power and the position of a certain country among the other countries as well as among the regional and continental countries. Recognizing and understanding the importance of Africa from different economic, political, territorial and ... aspects in the beginning of the third Millennium, and paying special attention to its core and peripheral countries, will be significantly helpful in designing effective plans on issues related to any country including the Islamic Republic of Iran, and therefore will ensure a great deal of success with the least time and expense. The present research, in addition to emphasizing the potentials and the important and effective geopolitical factors on the position of each country, attempted to identify the important and effective countries in different regional and continental levels as well as their areas of effectiveness.

From a theoretical point of view, modern technology causes changes and makes the transition from tradition to modernity in different ways in the economic, cultural and environmental structures and the relationship among them. Modernization in Qaen has a longer history in agriculture sector than in any other field.The article studies the effects of reconstruction in the agriculture sector in the town of Qaen in Southern Khorassan, with regard to deep and half- deep water wells. It also studies the economic as well as cultural effects of this issue in the region.The first set of agricultural wells were dug by Sefeed Dasht irrigation company in Nimblouk area of Qaen in 1964. This was much before any other sector to deal with modernization process in the region. The reason for this was the House of Alam, one of the most influential figure in Pahlavi dynasty, and their economic and political influence in the region. They provided the area with modem machinery in the agricultural sector and deep and half-deep wells. The first tractor was used in the area in 1948. In fact, change in the technological structure caused changes in other sectors. Obviously, technological changes in the area have had positive as well as negative effects. The negative ones are more environmental. They are mostly the result of management problems in the environmental and natural resources in the region.

The exterior- oriented urban transfiguration, being chiefly urban- penchant and centrality- tended, has caused remarkable structural changes in urban- administration and urban- habitation in the recent centennial in Iran, in such a manner that the population of urban- dwellers in the country grew up from nearly 20.6% in the year 1900 to 61.3% in the year 1996. This change has been induced in by the impetuous expansion of city-dwelling areas in the country. Meanwhile, the urban network of the country was disrupted and hence the population concentration in metropolises is considered as one of the outstanding characteristics of the city- administration in that period. And now this very procedure has been the root cause of expansion of peripheral dwelling and the cropping up of satellite and spontaneous towns on the outskirts of the metropolises. On the one hand, a pertinent arrangement and cohesive planning for a better standard of living with a conducive urban environment for the urbanites, and on the other hand, the control and check on the parametric inhabitation and cropping up of spontaneous and unplanned townships have rendered the need for configuration and planning of well-designed new towns quite definitely indispensable. Nevertheless, the configuration of the new towns, having been planned usually to cope with the demand of overspill of the metropolises, is quite a new conception in Iran and it goes back to a couple of decades. A glance on the placement of such towns in the urban - dwelling system of the country from the point of view of constructional conditions and the people settled therein, manifests the inefficiency of these towns. The reasons for this shortcoming should be traced in the major urban- expansion policies of the country, inefficient management of the structure and implementation scheme of these towns, and fmally the limitations brought about by non- existence of identity in the new towns. The amendment of such deficiencies can play a vitally important role in the promotion of placement of new towns in the urban system of the country.All in all, the most dominating problems that have caused a languid performance are: First: Lack of regional planning and attending only to the town plans resulted, in most cases, in inflicting irreparable losses to environmental potentials and to resources which could not be restored. This factor involves various developments and constructions which in the case of new towns bears a strong perspective.Secondly: The announcement by the ministry of housing and town- building that these towns are being built without government aid, means that none of the government organization and institutions with regard to satisfying the needs and wants of these towns, shared the responsibility. Consequently, this policy has brought about heavy expenses on the managements of the new towns.Thirdly: The most important problem now facing the new-towns in the world is the negation of their identity. As far as the new towns of Iran are concerned, engineer Kamrava says "I have to say with regret that the new towns we have founded lack a distinctive characteristic identity and have failed to create some dignity-bearing incentive for its devoted citizens".