GEOGRAPHICAL RESEARCH
Year:2004 | Volume:19 | Issue:2(73)|Papers Count:10

Evapotranspiration (ET) is one of the most necessary and important parameters in estimating crop water requirement as well as for designing irrigation systems. Determining reference ET accurately and using that in calculating the amount of required water for irrigation leads to more efficiency and saving water in agricultural section. For calculating ET lysimeter is used widely in different parts of the world. Kerman university jihad built one electronic weighing lysimeter in Kerman agriculture college in 1998. In this study, various methods of estimating grass ET were compared using data from the lysimeter and meteorological data from the university jihad weather station (reference) and Kerman airport weather station (non-reference). Comparing the ET values from the lysimeter and the results obtained from various methods showed that Penman-Monteith, Penman FAO-24 and Penman-FAO-PPP resulted the best estimation and Jensen-Haise was the least accurate. In the non- reference station Pristoly-Tylor, Penman1948 and Bliney-Criddle-FAO resulted the best estimation and Penman- Kimberly1972 was the least accurate.

A mesoscale model of the surface wind distribution over complex terrain is used. The model is based on thermally induced mechanism of the slope/valley wind system. It is developed to simulate temporal as well as geographical variations of the wind field.The model’s equations incorporate the effects of non-uniformities in surface temperature, roughness, and terrain elevation. Initial integrations of the model equations have been made to simulate flow patterns over Greater Tehran (Capital of I.R. of Iran) area and the vicinity during the occurrence of an upslope wind. The initial conditions are also assumed to be calm and cloudless.This study has extensive applications in the dispersion of pollution, wind energy and convergence activities. Furthermore, the model does not require very much computer time and speed.

Examining the morphological evidence on the quaternary glaciers in Iran has been of interest to many researches, However, the beginning of such studies can be traced back to Domorgan (1890) and Bobek. The latter began his work in 1933 and published the results of his research in 1955.In the last decade Iranian Geographers started a new series of research on the climatic conditions of Iran on quaternary period and it is evident that they achieved new results.Geomorphologists’ interest in climatic changes and traces of geomorphic evidence have led them to estimate the past climatic data. Using these methods in glaciology of Iran, show that there are four cold troughs in Iran. Being more widespread in quaternary age than present. In these troughs some traces of glacial period as cirques and ice capes are evident (Nematollahi 1383). This is very interesting for geomorphologists because these regions were much colder than the present during the glacial age. This means that the formative processes of these regions are different and it is possible for us to study the evidence of the formative process system of cold age in these areas.The results of this research show that there are one widespread ice cape and one big glacial valley in Salafchegan, located near one of the driest and hottest point in Iran (Quom).The analyses of climatic data currently recorded in Iran, on the one hand, and the existence of locations which show remarkable differences in terms of temperature with adjacent regions on the other, have attracted the attention of geomorphologists to such areas, as well as to their distribution.It is evident that, by focusing on the estimated environmental temperature, one can guess that these areas have also shown greater temperature characteristics during the cold periods in the past relative to other reigns adjacent to them.We call the regions which show greater temperature than the areas adjacent to them cold troughs. If the annual temperature of these cold troughs is less than 5c and their surfaces are flat, then we can formulate a hypothesis for the existence of ice capes. The aim of this paper Is to identify the cold troughs In Iran and to Investigate their geomorphic characteristic so that we can study the possibility of the existence of previous ice capes in these areas.The results of this research revealed, for the first time, the presence of ice capes and glacial valley in Salafchegan.

In this paper after introducing geographic features of Gamasiab basin in the west of lran (Nahavand plain), some general characteristics of the basin, as well as geologic, hydrologic and geomorphological characteristics are discussed.The geomorphic features of the region and processes are so varied that we can find a variety of features and phenomena produced by tectonic, fluvial, glacial, karstic , mass movement, and anthropogenic processes. All these make the region a unique place for studying many geologic, geomorphic and hydrologic physical landforms.The aim of the paper is investigating the suitability of the basin for geomorphologic and hydrologic studies for B.S. and M.S. students in geomorphology and hydrology fields and emphasis on the need for further research for development plans in the region. Of course recognition of physical potentials of the region can lead to the development of ecotourism and scientific tourism in general.

Many villages and urban areas are located on the traces of rivers. The water of these rivers is used for irrigation, drinking and industrial activities. On the other hand, the topography and soil of these lands are very suitable for settlements. However, factors such as: the dynamism of the river, change of discharge and meandering, cause these lands face some problems like flood and direction change of rivers.This article aims to survey the meandering pattern of Talar river in the coastal plain of the Caspian Sea. In order to do this, coefficient of curvature (Leopold & Wolman method) and central angle (Kornise method) were used. The results showed that the mean sinuosity coefficient of curvatures was 1.39, which indicates high meandering of Talar river. On the other hand the sinuosity indicator (curvature coefficient) showed that 26.4 percent of meanders in Talar river were developed ones. Also, using central angle (Komise method) showed that the mean central angles of Talar river was 129.1 degree.Therefore, 60.4 percent of curvatures of Talar river are developed and 25.5 percent are considered as very developed meandering. These coefficients show the necessity of using engineering methods for making the bed of this river stable.

Temperature is one of the important thermodynamic meteorological elements the change of which can cause many physical, chemical and environmental variations. The history of measuring temperature is relatively long compared to that of other elements in meteorology. In spite of some evidence and experts" belief about the global warming in the years 1947 and 1948, the idea of stationary climatic condition persisted till 1970s.Many research done at national, regional, and global levels indicate an increase in temperature in many parts of the world. In other words they prove an increase in the mean global temperature. Although there is a marked increase in maximum temperature in many parts of the world owing to its lower increase rate, compared to that of minimum temperature, DTR has decreased. The results obtained for maximum, minimum, and mean temperatures are quite different from one another. Positive trend for minimum temperature in majority of Iranian synoptic stations especially in those located in cities with high urban growth rate, are remarkable. For instance, it is strong in Esfahan. Moreover, we found a jump in annual temperature series in the 1970s that is consistent with the jump in many places in the world. DTR in large cities like Esfahan, Shiraz, and Tehran has decreased significantly. In this regard, a 4°C decrease in Esfahan can be noticed. In addition to some exceptions, quality and quantity of trends are also discussed.

Famenin-kaboudrahang plain is located in the north of Hamedan province in Iran. The sedimentary rock of the aquifer is about 70-100 meters thick and because of the excessive exploitation of the aquifer the water table goes down about 2.5-3m every year. At least 19 small and big sinkholes have been formed on the plain during the past 10 years and this has worried the inhabitants of the region. Surveys have been done and the specifications of these sinkholes are recorded. The results show that the existence of the holes, water canals, joints and fracture systems in the limy bed rock and the pumping of water from wells are the main reasons for the development of these sinkholes and other factors such as sandwashing of layers, the gas coming out from the wells and fast fall of water table are the other contributing factors. To avoid this phenomenon, drilling in the bed rock should be stopped, suitable gravel pack should be used and all wells with high water yield dug in the bed rock should be filled.

If we consider the urban sustainable development as the economic efficiency, social equity, and environment protection, one important element will be the optimization of urban land use. Today, this factor is not well much taken into account in our cities such as Yazd.Yazd, the appearance and origin of which get back to the Islamic era, has experienced two Development Scenarios, like the other old cities ifl Iran. The first was the organic model which was in use until Pahlavi time and led to surface expansion, especially before the Land Reform in the 1940s. Its effects can mostly be seen in urban population growth. In this process, fundamental changes were generally of content elements, and growth patterns of the city remained compressed.The other scenario experienced in Yazd in the last 25 years, was non-organic model of growth. In this process, the surface growth was faster than the population one. The city spread horizontally, and the space provided was more than what peoples needed. What came out of this growth are as the following:Loss of congruity among parts of the city; scattered development and haphazard expansion; abandonment of old parts of the city; low population density in the city as a whole; difficulty in" providing city services such as pipewater, electricity, etc; undesirable quality and proportion in land use; pieces of land with no use in the city; expansion of the city on the reserved lands of protected areas; environmental problems, hoarding lands, etc... .The process of land supply has an important role in the development of the city. However, the hasty process of land supply in Yazd has led lots of wast rural areas, with low population density, both agricultural and waste lands, to be within the city region. Without efficient management and plan, lands are divided, sold, and bought illegally. Different indexes of growth in the regional and national analyses indicate that Yazd has been greatly suffered from this process. Findings also show that in the present city region land is not used properly. As a result Yazd needs no expansion for the next 25 years.

Studying the process of smuggling goods, its causes and development, and its dimensions in the future is crucial for the national economy. It is not however well appreciated in the academic societies.The present study as an initiative, without going into details, or considering the conceptual matters, or dealing with general views makes attempts to investigate the issues such as: the present forms of smuggling goods, the campaign against it, and in particular, the inefficiency of the current measures taken by the government to stop smuggling in Hormozgan province. Some basic parts in this paper are as the following.I.A brief review of overall and national performance of Hormozgan province in preventing smuggling goods.2.Presentation of evidences indicating the inefficiency of the campaign against this common and continued phenomenon at the frontiers.3.Classification of the causes for the campaign failure.4. summary and conclusions.