Physical Geography Research
Year:2008 | Volume:- | Issue:65|Papers Count:10

The climatic, geographic and topographic characteristics, ecological conditions, forest and pastures, strong water resources, high vegetation, wild life and various hunting areas of Kurdistan province are strong tourist centers. In this research using GIS potential of suitable zones for claiming, rocking, ranging, visiting the nature, thermal spring, ski and winter sport, water sports and fishing were studied. Based on objectives of research all the needed data including altitude, slope, vegetation, water resources, rivers and thermal spring gathered and classified. Then with overlay the data layers in GIS environment using Boolean model, suitable zones for each of ecotourism areas were determined. Result of this study indicates about 80 percent of total area on Kurdistan province have potential to develop of various touristy activities. 

The changes in time and location of surface temperature from a water body has an important effect on climate activities, marine biology, sea currents, salinity and other characteristics of the seas and lakes water. Traditional measurement of temperature is costly and time consumer due to its dispersion and instability. In recent years the use of satellite technology and remote sensing sciences for data acquiring and parameter and analysis of climatology and oceanography is well developed. In this research we used the NOAA’s Satellite images from its AVHRR system to compare the field surface temperature data with the satellite images information. Ten satellite images were used in this project. These images were calibrated with the field data at the exact time of satellite pass above the area. The result was a significant relation between surface temperature from satellite data with the field work. The magnitude of the errors in between was low and in order of being acceptable. The information of all satellites were images extracted by ERDAS software, and the “Surfer” software is used to plot the isotherm lines. 

In order to identify the pressure patterns causing the cold weather over the northwestern Iran, daily lowest temperatures of six stations of the study area during January- March months of the 1986-2003 period were obtained from Meteorological Organization of Islamic Republic of Iran (IRIMO) in the quality controlled format. According to the defined threshold, the very cold days were extracted and their pressure distributions were classified to four patterns using the Spss Principal Component Analysis and Clustering programs. These four pressure patterns are: western anticyclones, Oral Low pressure, Ararat High pressure, and Zonal pattern. These patterns showed that in 70 percent of the days a deep 500 hPa trough located over Iran brings very cold air to the study area beneath its rear part. And at the surface a strong anticyclone develops. On the 30 percent of the times the surface radiational cooling is the major cause of the cold weather.

Dust storms are destructive climate Phenomenon which damage farm, installations, roads, traffic and etc indemnifiable. This Phenomena at dry and pertaining regions of the country as environmental perils, is effected by particular atmospheric condition. If the origin and extention of this phenomenon be recognized the damages can be decreased or counteracted. The studied about dust storm show thirteen-year statistical period (1993-2005). There was less than 5 days dust storm in a year in stations Ghoochan, Torbat heidarieh and Kashmar, while there was more that 35 days in sarakhs sation. This research shows that main of there system which lead to dust storm follow synoptic conditions. On The level of the map in stormy day the low-pressure center closes around the southern part of Khorasan and Afgenistan. The central pressure of this low pressure, usually less than 1000 hecto-pascul. In contrast, the high pressure center closes on the Caspian Sea and usually in its southern part. The central pressure of Caspian Sea is more than 1015 hecto-pascal in most of the time.The center of cyclone closed in easthern and north eastern part of Afganistan, at the level 850 hecto- pascal. It also, covers tongue cyclone of the southern part of Khorasan. usually 144 geo- potential curve, especially during the storm blowing pass the northern part of the case study region. In contrast anticyclone closes cover the Caspian Sea and Turkmanstan. It s height is more than 148 dca-meter geo - potential. So, the cyclone and the anticyclone cause strong winds speciall in southern part of Khorasan Razavi province, by making thermodynamic system and thermodynamic pressure.

Flood is one of the major natural disasters in Iran, which is mostly, affected most parts of the country and caused hazards. Therefore, identification of the area with high potential risk of flood occurrence is the main purpose in order to the flood control and reducing its damages. In this research the role of the flood routing in identification of the area with high potential flooding has investigated after discharge routing of the sub-basins in the main channels to the outlet. The indicator watershed of Kasilian as the study area in the northern flank of the Alborz range divided to 3 sub-basin which was processed geometrically using GIS and Hec-HeoHms extension. With using HEC-HMS model and emission of individual repetition of the sub-basins, the homogenous flood hydrographs have gained in relation to the recorded precipitation calculated for different sub-basins. With consequent emission of sub-basins during the processes of the model running, total discharges of the basin calculated after flood routing in the main channels with ignoring of the sub-basins. Finally, sub-basin with most effective in flood production has determined as a high flooding basin. The flood routing in channels have shown that the rate of flood occurrence has no related the discharges of the channels. 

Volcanic cone of Taftan is located in southeast of Iran, northwest of Khash city. While there is water vapor and sulfur dioxide exhaustion from its peak, the presence of deep valleyes and irregular shape of drainage system demonstrates long term erosion and complicated development of drainage system. For the evaluation of lithology, slope degree and slope aspect effects on drainage density, after digitizing of topographic and geologic map, we prepared Digital Elevation Model(DEM), slope degree, slope aspect, drainage system and lithology maps of Taftan cone in ILWIS software. Then drainage densitis in all formations, slope aspects and slope degrees was extracted. Data analysis reveals that, except alluvial fans and terraces, drainage density is more in old formations and steeper slope than in modern formations and lower slopes. Drainage density is more in east, southeast aspect, which are corresponding to older formations, than other aspects. Investigation of drainage pattern in study area shows that drainage pattern in younger lavas is parallel while in older lavas is dendritic. Nevertheless, there are irregularities in patterns. The comparison of old and new alluvial fans in IRS satellite images illustrates considerable differences in drainage patterns so that drainage patterns in new and old fans are divergent and convergent downward respectively. This is due to agradational process in new fans and degradation process in old ones. It can be, to some extent, accepted the viewpoint of some researchers like Parker about drainage density and pattern relation with time passing and slope angle in study area but there are complexities in drainage characteristics especially in channel pattern.

This study intends to assess the evolution of characteristic of Jajroud alluvial fan that spreading on Varamin plain. Alluvial fans are one of the most dynamic landforms in arid regions. There are some different and opposite opinions on formation of alluvial fans and their evolution that submitted by scientific papers and reports. The object of this research is explanation of characteristics of Jajroud alluvial fan and assessment of effective factors on its formation and evolution. In this study we use satellite image of IRS (2002), aerial photos, 1:25000 and 1:250000 digital topographic maps and 1:250000 and 1:100000 geological maps as basic materials. Also we used digital image processing and map producing softwares. For the image processing PCI and Ilwis software’s and for preparing of maps, Arc\GIS, Freehand and Microstation software’s were used. In spite of this, in many cases with field check and observation of some natural and artificial profiles on the surface of alluvial fan we collect some valuable and supplementary information for controlling and supply accurate evidences. For this reason with taking of photos and tracing of graphic logs we collect some information about the fan. At the end, we used some tectonic activity indexes for explain the effect of tectonic activity on Jajroud alluvial fan. The result of this study shows that evolution of Jajroud alluvial fan affected by tectonic activities and climatic change and the base level change in long time and human activity in short time. 

In this study spatial pattern of seasonal and annual precipitation in west mountainous region of Iran were investigated using a 35 hydrological year from 1965/66-1999/00 in 170 meteorological stations. In order to evaluate and analyze spatial differences across study area, time distribution of precipitation during the year were also investigated using precipitation Concentration Index (PCI). The results showed that the precipitation regime in north of study area with maximum in spring season is different from precipitation regime in southern part of study area where the maximum occur in winter. In general, winter and autumn are the rainy season in middle and southern parts of the study area. Summer is dry season in almost the entire region. In this season rarely precipitation may occur somewhere due to orographic activities. The observed similarity between winter, autumn and annual precipitation maps indicated that the precipitation in the study area is controlled by latitude and altitude factors. This similarity also implies that the precipitation mechanisms and triggers in most fraction of study area are similar.