Alireza Ildoromi; Habibeh Rouzbahani
Volume 18, Issue 48 , June 2014, , Pages 37-60
Abstract
Mass movement is one of the natural hazards with regard to frequency of which and its strength there are two consequences direct (blocking the rads and the direction of waterways, burring the residential areas and service installations) and indirect consequences (environmental unpleasant effects, making ...
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Mass movement is one of the natural hazards with regard to frequency of which and its strength there are two consequences direct (blocking the rads and the direction of waterways, burring the residential areas and service installations) and indirect consequences (environmental unpleasant effects, making the soil useless, increasing the sedimentaion and decreasing the capacity of dams). The present research was carried out on Kalan dam watershed in Malayer to distinguish the effective factors in the mass movement and recognize prepared areas for mass movement and appointing the weight which states the standard role of these factors in mass movement occurrence. Factors such as lithology, space of faullts, slope, altitudinal surfaces and rainfall are chosen as the most effective factors in the mass movement occurrence. By using geological maps, topography and aerial photos in the from of geographical information system (GIS) and ArcGIS software, we used LNRF model in the maps in the numerical and stratum from for analyzing the obtained data through studying the effective variances as the research conceptive tools. We finally prepared the zoning map of the mass movement danger by combining various strata (layers) through weighting to the effective factors and their algebraic conclusion and the results show that the LNRF model is a good competence to study the data and zoning of mass movement in Kalan dam basin.
Hamid Noori; Alireza Yildroomi
Volume 16, Issue 41 , November 2012, , Pages 197-236
Abstract
This research, one of the most covering rainfall times (from1381/8/6 to 1381/10/5) in Iran study and then synoptic and dynamic analysis of it's the heaviest rainfall cluster (from 1381/9/15 to 1381/9/20) explain using environmental to circulation pattern method. In this time more than 60% of Iran stations ...
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This research, one of the most covering rainfall times (from1381/8/6 to 1381/10/5) in Iran study and then synoptic and dynamic analysis of it's the heaviest rainfall cluster (from 1381/9/15 to 1381/9/20) explain using environmental to circulation pattern method. In this time more than 60% of Iran stations experienced rainfall and also, the number of heavy rainfall events were recorded in the southern coastal Caspian see. After drawing of Isorain maps in studied days, rain maximum points and its gravity centers calculated. Then, pressure surface patterns, geopotential, humidity advection, front, jet stream and Q-vector maps were drawn in different levels. Analysis of pressure of see level maps showed that pressure gradient reinforcement between Black see high pressure and Mediterranean low pressure and between Black see high pressure and the eastern north of Caspian sea low pressure are effective to produce these heavy rainfalls in west, southern west of Iran and the southern coastal Caspian sea. Maps geopotential showed that there are two main patterns in this studied time, as role of the eastern north of Caspian Sea trough (part of long through of Mediterranean) is very important. Analysis of humidity advection maps showed that Mediterranean sea and Red sea in upper levels and Persian Golf and Oman sea in lower levels are sources of humidity for heavy rainfalls, as them role in different days aren’t alike. However, heavy rainfall events in the southern coastal Caspian sea were provided via Mediterranean sea in 500(ha) level, Mediterranean sea and Red sea in 600 and 700 (ha) levels and all of main sources of humidity (Black sea, Mediterranean sea, Persian Golf, Red sea and Caspian sea). Polar front, north of Red sea-north of Persian Golf front and composition of subtropical jet stream and polar front jet steam in the east of Iraq can be from reasons of producing and strengthening of vertical movements. Also, analysis of Q-vector maps with point of convergence regions shows the important role Caspian sea, Mediterranean sea, Black sea, Persian Golf and Oman sea to producing of raising movements in different levels and times and its follow to forming of heavy rainfall events in the southern coastal Caspian sea and Iran.
