Physical Geography Research
Year:2009 | Volume:- | Issue:66|Papers Count:10

Intense temperature variations are not only an unfavorable phenomenon for life but have adverse effects on natural elements of structures and installations. When the temperature falls bellow certain levels, the conditions for organic activity, become harsh. This level is known as temperature threshold of life. Similar thresholds can also be defined for machinery, structures and installations. Further, when the temperature falls below zero degrees centigrade, its effects on living and non-living elements of the environment are greatly enhance. The December 10th-15th 2003 cold wave killed a number of human and animals hampered the intercity as well as urban traffic. Between 70 to 75 percent of the area of the country was frozen due to penetration of an extensive cold wave on December 11th-12th 2003, for the width of low. Temperature Goveraga in Iran, ING pressure has declined considerably and the houses administrations and didactic centers warm up process have serious problems. This was resulted from a Siberian high pressure trough formed around Baikal Lake. This led to, a considerable fall of temperature amounting to more than 15oC in most of the stations. A high elevation center at 500 to 700 hecto-Pascal levels formed prior to the beginning of cold wave on the Eastern Europe and moved over Caspian Sea and eastern' Ukraine in the following days leading to slow down of the trough and its blockage in eastern Iran and Afghanistan, for 4-5 days, amplitude portion of country specially western half, has been affected by Rick, thus resulting in continuation of cold weather fall over Iran.

The aim of this paper is detection of exist of significance climatic trend in west-half of Iran. It's used monthly data of 16 climatic variables on 12 selected synoptic stations in period of 50 years statistic (1951-2000). The variables divided to two temperature and humid groups. The analysis methodology of the study is based on multivariable statistical analysis and Box- Jenkins forecasting models.The results show the temperature variables such as average minimum temperature, absolute minimum temperature and dew point temperature had significant trend with different direction. Some stations such as Esfahan, Tehran, Bushehr, and Tabriz, had positive significant trend and in some stations such as Uremia, Hamadan, Khorram-abad there were negative significant trend. We didn't find any significant trend in moisture and precipitation variables (humid group).

The Tajan River is one of the most important rivers in the north of Iran. It seems that in respect of its meander design and pattern, passing over the block's fault and deviations along its way, it's influenced with active neotectonically movements in the region.Although being meander in rivers, in the level of a flood water field with very low gradient, isn't unexpected but existent abnormal like unusual contortions, local expand of meanders, braded formation and sudden changing in ways in different periods, are targets of passing from an active tectonically area. Hence, to recognize the method of acting in these tectonically activities and to recognize the amount of effects of tectonically movements in modeling of rivers behavior, some geomorphologic indexes such as SL, Smf, AF and etc, are used. Because the model of expand & evolution of drainage networks, is one of some indexes which are more sensitive about changes of earth made activities. In this research to examine the changes of river headstock, some aerial photos of several periods in scales of 1:20000 & 1:55000 and satellite image of Landsat TM and field processes in two turns were used. Also soft wares like Ilwiss 3.3, ArcGIS9.1 and Photoshop was used in sketching & Cartographic analysis.This research's results show that region in aspect of neotectonically or young tectonically is active because of coefficients obtained from geomorphology's indexes and geodynamic station's data but the amounts of activities aren't the same among regions. In the other side, 4 old waterways were revealed by relying to morphological witnesses through studding the aerial photos, geologic map and the important faults of region in cross of Tajan river and topographic quantitative analysis and the type of Tajan river.

The southern shore of Caspian Sea is subjected to several atmospheric factors due to its geographical position. North Atlantic osciliation (NAO) one of the effective phenomenon's affects the most part of hemisphere included Caspian Sea. In this research negative and positive phases of NAO considered with variability of temperature and precipitation of southern shores of Caspian Sea in a 30 years periods (1974-2003). The results of research show that positive phase of NAO accompanied by increasing of precipitation and decreasing of temperature and with concern to negative trend of NAO index, precipitation of this region decrease and temperature increase as such.

One of the basic subjects of climatic studies, especially constructions and residential environment, is an architecture which is in harmony with the climate, and the programmes of energy consumption, the question of heating them in cold seasons and cooling them in warm seasons of year in order to reach to the approximate heat comfort of human beings, the extent of need of a particular N-day period of degree- days of cooling and heating which are called CDD and HDD for whose cal calation the following formulas can be used, CDD=S(T-q2), HDD=S(q1-T) in which T is the average of daily temperature, and q1 and q2 are the temperature threshold in centigrade.The region of Azerbaijan is located in the north - west of Iran and is considered, according to mountain topography and climate, one of the cold regions of Iran.According to the statistics of 1381, its population is about 7,357,456. According to the special geographical and climatic conditions and its population, a great deal of energy and fuel is needed each year for heating the residential environment of the area under study.In this essay, the degree- days of need for monthly and annual heating and cooling of the studied regions' stations are ca1culated,then by using Arc\ View software the data are processed in GIS environment, and the annual and monthly classification plans of the degree-days of need for heating and cooling are designed and drawn digitally and are colored.

In this paper, the temperature and annual precipitation data has been applied in 44 years for the synoptical stations northwest zone of Iran. Among the stations, eight of them, which have the perfect data and coverage, has been considered to analysis applied. In this study Transfer function models have been used to analysis time series. In this method, firstly, the stations have been modeled then the data has been analyzed and predicted on them. Finally, from the process exam the considered stations have been examined, and the significant of fluctuations process of temperature and precipitation have been characterized. The results show that Mianeh, Tabriz and Maku stations have significant process. In process of annual precipitation, according to the results of exams, Tabriz, Ardabil, Urmieh and Khoy stations have significant process and in all of them annual precipitation has falling process.

Saffron, has a very high economic value, is a substantial part of non-oil export of Iran.This crop with a long history in Iran requires especial careful planning. The identification of suitable areas for cultivating this product in Iran could be one of important steps towards this aim. In order to identify these areas we should use spatial data and non-spatial data. Nowadays, due to the progressed has done in the field Geographical Information Systems, we are able to use spatial data and non-spatial data, which also proved facilitates spatial data analyses according to relevant models. In this research by taking account Saffron ecological requirements and determining the criteria, we have used Multi-criteria Decision Making Decision (MCDM) approach and Analytical Hierarchy Process (AHP), as model and Arc\GIS software for both modeling and for analysis of spatial data. Regionalization processes include: data collection, statistical analysis, input, clustering and selection criteria, spatial modeling and overlaying Finally Qazvin province based upon Saffron cultivation has been classified to suitable, relative suitable and non suitable classes. We generally concluded that Multi-criteria Decision Making Decision (MCDM) approach and Analytical Hierarchy Process (AHP) could be useful for Land suitability Saffron cultivation in the study area.

Weather process prediction is the tool for managers to planning the future political for maximum operation. The aim of this research is relation investigation of large scale synoptically patterns with Seasonal rainfall of Khorasan province. In this research, we have analyzed 37 years of rainfall data in khorasan province that is located the northeastern part of Iran .We attempted to train Adaptive Neuro-Fuzzy Inference System (ANFIS) based on synoptically patterns with 37 years of rainfall data. For performance evaluation, ANFIS predicted outputs were compared with the actual rainfall data. In This Study, at the first step, the relationships between synoptically pattern variations including Sea Level Pressure (SLP), Sea Surface Temperature (SST), Sea Surface Pressure Difference (DSLP), Sea Surface Temperature Difference (DSST), Air Temperature at 850 hpa, geopotential high at 500 hpa level, Relative Humidity at 300 hpa are investigated. in the second step, model was calibrated from 1970 to 1992.Finally, rainfall prediction is performed from 1993 to 2002. Simulation results reveal that Adaptive Neuro-Fuzzy Inference System (ANFIS) is promising and efficient.