نشریه جغرافیایی سرزمین
پیاپی 2 (تابستان 1383)

In order to study and identify the pressure patterns responsible for the floods of theGorgan River the dates of the sudden increase of daily discharge of the river wereextracted for each calendar month during the 1968-1998 period. For each calendarmonth one intensive and widespread flood was selected. The weather maps of thesedays at the surface and 500 hPa levels were analysed and the main pressure patternswere determined.The results showed four distinctive patterns: cyclonic, anticyclonic, warm front, andlocal cold front. The anticyclonic pattern was the most frequent one which is followedby the cyclonic pattern.

The city of Yazd is chosen as a sample for studying the principle and methods ofclimatic designing in arid and semi-arid regions. After represnting some climaticcharacteristics of the city, we have paid attention to the human bioclimatic aspectsaccording to Terjung Model and the specification of monthly physiologic climate. Theresults indicate that only in October and April there has been dominant the diurnalthermal comfort conditions, while in May and September, such conditions have beenprovided in lower rates. In June, July and August, there is very rigid bioclimaticcondition due to hot weather, and finally in December, January, and February, therehave been hard biological conditions owing to the cold. In the next section, we havestudied principles of climatic design of bilding based on the Mohoney method andthereby the architectural setting have been presented according to the Glvoni structuralbioclimatic table. In the last section of this study, using the Sun path diagram, lightpermittingprinciples of buldings were presented for the city of Yazd.

One preventive in instrument for contamination of wells extracting groudwater forpublic supply is setting up protection zones around wells. For determining qualitativelimit of Sari drinking water wells, Information of 21 wells that control by water andwastewater company of Sari. So, Protection zones of Tangh Lateh has greatest areaand is going to be least toward Sari. Protection raduis is a function of hydrogeologicalcharacteristic, some extraction water and time of travel zone. The results fromcorrelation diagrams between this parameters and protection raduis explain two point:1- Some parameters has a different effects on up gradient protection raduis and downgradient protection raduis. 2- Saturated thikness has an effective role in value ofprotection raduis in Sari. With respect of correlation diagrams between effective raduisand up, down and prependicular protection raduis,The rate of protection raduis isdetermined appoximately.The results from hydrogeochemical analyze show that theprotection zone Tangeh Lateh wells has low contamination and rate of contaminationis increased toward Sari in protection zones of drinking water wells.

Ashkzar region in Yazd province has been subjecting to fissures on the ground sincethe last two decades.This has caused some damages to dwellers. The fissures haveaffected some previous landforms as nebkhas and dunes and have made up somegullies and depressions that they fill with water on rainfalls times. These fissures werecreated by subsidence. Statistics analysis such as Analysis of variance, Tukey –Kramer Analysis,and t-test, and also laboratory and field studies show that this landsubsidence was resulted from ground water overconsuming and then falling the watertable. The Subsidence rate is investigated through external coming up of pipes andBouwer (1978) method. According to, amount of subsidence obtained is estimated tobe about 62 cm from 1973 to 2001

Alluvial fans are one of the most important geomorphic features in arid and semi-aridregions. In Mighan basin, because of it’s semi- arid conditions. The Alluvial fans canbe seen everywhere. The city of Arak is located on an alluvial fan that its Radial is 13kilometers long. In regarding, there are other large alluvial fans in the Mighan basinthat are the location of a few villages and farms. In contrast, in south western of Arak,there are many alluvial fans that didn’t provide and positive environmental condition.This condition depends on stability of alluvial fans. For understanding these aspects ofalluvial fans, one should study their peculier morphometric characteristics. In suchstudies, situation of shape, area and slope of alluvial fans, usually is analyzed withgeomorphology of their drainage basins. In this paper, results of the study betweenarea and slope of 24 alluvial fans with their drainage basins have been shown bymathematical models and regression figures.

Investigating slope instability and determining areas prone to slope movements bymeans of GIS has been considered by researchers in the past recent years; however,sufficient attention has not been given to the methods employed in GIS.The present article uses a cell analysis method in a slope instability studyconducted at Sanandaj Country, and has obtained an appropriate model fordetermining prone areas. While testing the model, the cell analysis method has beencapable of assessing the factors influencing slope instability and creating modificationchanges in weights and coefficients

Investigating slope instability and determining areas prone to slope movements bymeans of GIS has been considered by researchers in the past recent years; however,sufficient attention has not been given to the methods employed in GIS.The present article uses a cell analysis method in a slope instability studyconducted at Sanandaj Country, and has obtained an appropriate model fordetermining prone areas. While testing the model, the cell analysis method has beencapable of assessing the factors influencing slope instability and creating modificationchanges in weights and coefficients.

Evidence has been provided of two mountain glaciations in the 4000 m-high, currentlynon-glaciated Kuh- i -Jupar in the semiarid Zagros: an older period during the pre-LGM (Rissglaciation, c. 130 Ka) and a younger one during the LGM (Würm glaciation, Isotop-stage 4-2:60 -18 Ka). During the pre-LGM glaciation the glaciers reached a maximum of 17 km inlength; during the LGM glaciation they were 10-12 km long. They flowed down into themountain foreland as far as 2160, i.e. 1,900 m.The thicknesses of the valley glaciers reached 550, i.e. 350 m. During the pre-LGM a 23 kmextended,continuous piedmont glacier lobe has been developed parallel to the mountain foot.During the LGM the glacier termini mainly remained isolated in the mountain foreland.During the pre-LGM glaciation the ELA ran at 2,960 and during the LGM-glaciation at 3,060m a.s.l, that is 1.590, i.e. 1,490 m below the current theoretical snow line. Thus, a temperaturedepression of c. 11-16°C, i.e. 10-15°C is proved for the SE-Iranian highland, c. 130, ie. 60-18Ka ago.