Synoptic Origin of Cold Temperatures Over the Northwest of Iran
بهلول
علیجانی
استاد گروه جغرافیا، دانشگاه تربیت معلم
author
محمود
هوشیار
دانشجوی کارشناسی ارشد اقلیم شناسی و برنامه ریزی محیطی - دانشگاه تربیت معلم
author
text
article
2009
per
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.
Physical Geography Research
University of Tehran
2008-630X
0
v.
64
no.
2009
https://jphgr.ut.ac.ir/article_27756_6d4679826b67a0484feeaa854aec4a3d.pdf
Statistical Synoptic Analysis of Dust Storm in Khorasan Razavi Province (1993-2005)
حسن
لشکری
دانشیار دانشکده علوم زمین - دانشگاه شهید بهشتی
author
قاسم
کیخسروی
دانشجوی کارشناسی ارشد اقلیم شناسی - دانشگاه شهید بهشتی
author
text
article
2009
per
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
Physical Geography Research
University of Tehran
2008-630X
0
v.
64
no.
2009
https://jphgr.ut.ac.ir/article_27757_468d17574c23e5540ec5023853a3817d.pdf
Possibility Study of Ecotourism Development Zones in Kurdistan Province Using Geographic Information System (GIS)
منوچهر فرج زاده
اصل
دانشیار گروه جغرافیای دانشگاه تربیت مدرس
author
رفیق کریم
پناه
کارشناس ارشد جغرافیای طبیعی دانشگاه تربیت مدرس
author
text
article
2009
per
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.
Physical Geography Research
University of Tehran
2008-630X
0
v.
64
no.
2009
https://jphgr.ut.ac.ir/article_27758_74dd1836444eb633ca2b7c48635b27c2.pdf
Flood Potential Production Using HEC-HMS Model in GIS Environment (A case study; Kasilian Watershed, Iran)
کریم
سلیمانی
دانشیار مرکز سنجش از دور دانشگاه مازندران
author
محمد بشیر
گنبد
کارشناسی ارشد دانشکده منابع طبیعی دانشگاه مازندران
author
سید رمضان
موسوی
مربی دانشکده منابع طبیعی دانشگاه مازندران
author
شهرام
خلیقی
استادیار دانشکده منابع طبیعی دانشگاه تهران
author
text
article
2009
per
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.
Physical Geography Research
University of Tehran
2008-630X
0
v.
64
no.
2009
https://jphgr.ut.ac.ir/article_27759_18f82eff0144ed4af15743113dbd268e.pdf
تحلیل مورفومتری و مورفولوژی شبکه زهکشی در مخروط آتشفشانی تفتان
شهرام
بهرامی
عضو هیات علمی دانشگاه زنجان
author
مجتبی
یمانی
دانشیار دانشکده جغرافیا، دانشگاه تهران
author
سید کاظم علوی
پناه
دانشیار دانشکده جغرافیا، دانشگاه تهران
author
text
article
2009
per
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
Physical Geography Research
University of Tehran
2008-630X
0
v.
64
no.
2009
https://jphgr.ut.ac.ir/article_27760_747be3ed0c5c0518ab5f75f056d4ab5e.pdf
Assessment of Effective Factors on Evolution of Alluvial Fans Case Study: Jajroud Alluvial Fan
unknown
author
text
article
2009
per
Physical Geography Research
University of Tehran
2008-630X
0
v.
64
no.
2009
https://jphgr.ut.ac.ir/article_27761_e776ccc31b4004a7b4d3d9e94c5c39c3.pdf
Investigation of Spatial Patterns of Seasonal and Annual Precipitation in Western Iran
طیب
رضیئی
استادیار پژوهشکده حفاظت خاک و آبخیزداری
author
قاسم
عزیزی
دانشیار گروه جغرافیای طبیعی دانشگاه تهران
author
text
article
2009
per
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.
Physical Geography Research
University of Tehran
2008-630X
0
v.
64
no.
2009
https://jphgr.ut.ac.ir/article_27762_7f01b42971b9ad0b85b5c5ba9f0e6636.pdf
The Comparison of Sea Surface Temperature by Satellite and Field Data of South Caspian
زهره
جلالزاده
کارشناسی ارشد فیزیک دریا، دانشگاه آزاد اسلامی - واحد علوم و تحقیقات
author
مسعود
ترابی
استادیار دانشگاه آزاد اسلامی - واحد تهران شمال
author
احمد
دالکی
استادیار دانشگاه شهید بهشتی
author
text
article
2009
per
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.
Physical Geography Research
University of Tehran
2008-630X
0
v.
64
no.
2009
https://jphgr.ut.ac.ir/article_27763_f2b85cca5d16a0ee0b07eab8df2277d2.pdf