JOURNAL OF NATURAL ENVIRONMENT HAZARDS
Year:2017 | Volume:6 | Issue:11|Papers Count:7

Soil erosion is a complex process that is difficult to measure the true extent of that. For analysis of runoff, erosion, and sediment is needed a deep understanding of production processes.The statistical methods often are used for calculating the total volume of sediment and erosion in basins, If there are enough information and statistics relating to sediment river flow. Since the in most of the basins in the world, there are not enough statistics and information, erosion intensity will be assessed using erosion estimation technology (the same model of erosion). the purpose of this study is evaluation of erosion and sediment yield in the Gabric basin, due to dam construction on the Gabric river, using experimental model of EPM with the help of GIS and performance of these systems in the basin erosion and sediment studies and ultimately reduce sediments in the basin and behind the dam order to performed to development and control projects. In this study were obtained from geology map with 1: 250000 scales, soil map available from the region, Land use/land cover map, Vegetation map, various statistics relating to the stations located around the basin and Digital Elevation Model (DEM). The results show special sediment and total sediment Gabric basin are 40.64 (m3/km2/yr) and 227725.8 (m3 /yr) respectively. Also, the amount of sedimentation and the total amount sediment generated in the basin are 243.84 (ton/km2/yr) and 1666355 (ton /yr) respectively, which is the classified basin of extreme class and applying various methods of erosion control are necessary for Gabric basin.

The earth surface and its landforms usually changes by tectonic activities. for defining tectonically activities and changes in the landforms of the earth surface, geomorphological indicators are one of the suitable tools. In the region, there are a few small and great faults and the main goal of the research is studying the movement and activities of the faults in the region in quaternary. To assessment the impacts of neotectonic movements in the region, we showed topographic and morphologic anomalies according to topographic and geologic maps, aerial photographs, digital elevation model, and also filed studies. To evaluate the rate of neo-tectonic activities in the basin, we have used geomorphological indicators includes; Bs, SL, T, AF, SMF, Hc, Hi, S and also geography information system. More indicators show tectonic activities and the movement of the faults. The rate of Bs is high. Besides, the rate of the profile of the river is different, because the main river has located inside a fault valley. SMF index is about 1.2 that indicates tectonic activity. The rate of AF reaches to 19 so that the area of the west is about four times the east segment. The index of hypsometric integral show uplifting especially in the west segment. The indexes of BS SMR are about 1 and 1.3 that both of them point out high rate.

The aim of this study is to examine the changes of snow-covered days in the elevation levels of Zayanderoud River Basin. The MODIS Terra and MODIS Aqua data were applied in the resolution of 500 × 500 m in the daily time scale from 2003 to 2014. A Digital Elevation Model of the Basin that was the same as snow data both in spatial resolution and projection system was extracted over the Basin. To explore the trend for snow-covered days for each of the elevation levels, first the frequency of snow-covered days was calculated over each of the elevations from 1500 to 3850 meters at the intervals of 50 meter and then the trend was examined using Mann- Kendall trend test. The investigations showed that in April and May the number of snow-covered days indicates a decreasing tendency in the high elevation levels of the Basin. In the months of November and December, the number of snow-covered days has shown a positive tendency over many of the elevation levels. The examinations of changes in precipitation regimes show that the shares of precipitation in the fall months have increased while the shares of winter months have decreased. It seems that the variation of precipitation shares have influenced the snow cover regime of the Basin, and snow cover decreasing trend accompanied by changes in the regime could have adverse effects for the Basin.

The aim of this study is to identify and analyze the position of the jet streams and moisture flux associated with extreme rainfall in the western regions of Iran during the period (1961-2010), using synoptic method, that four models were discovered in this area. To recognize the importance of jet streams in the formation of extreme precipitation, Network data levels in heights of 200, 300, 400 and 500 hp for these days, a series of data reinduction of protein NCEP / NCAR, was extracted by using the GrADS software and then proceed to check the total moisture flux convergence and divergence of the balance of 1000 hPa to 400 hPa levels, for each of the four synoptic patterns discussed above. To identify sources of nourishing the moisture such as rain, as well as identify the extent of nourishing the high levels of moisture into this system, rainfall in the region this work was done.Results showed that extreme temperature difference between the surface and high levels in the cold season is due to the presence of polar high-latitudes of the northern and western winds activities (Along with the creation and transfer cold holes and deep trough landing). So, in a situation of instability west, the presence of a low pressure core at high levels and rapid flow of warm and moist air at low levels is effective. Severe convective low-level rise has been caused by western winds along the polar front. In this way, the polar jet streams accompany landing of western winds with speeds of more than 60 meters per second along. Left Out in the core jet stream (second quarter) that matches the atmosphere of the West, the curvature of the winds into the Arctic air mass will cause decrease in curved volubility and increase in its area. As a result of the expansion of the air mass at high levels upside and unstable air mass will form.The curvature of the meridian wind jet streams toward the poles cause warm temperatures at the front axle of landing?

The purpose of this study was to evaluate the impacts of climate variables on yield and risk of Iran’s wheat production. In this context, crop year data were collected from 1982-83 to 2014-15. Considering crop season, monthly data were aggregated into seasonal data. Iran was divided into four climatic zones. To optimal selection of predictor variables, Feiveson algorithm was applied. To test the effect of climate variables on wheat production, a Just-Pope stochastic production function was used for each zone. To estimate the panel with fixed effect model, considering the volume of data, Feasible Generalized Least Squares (FGLS) approach was applied.Overall, the results showed that the effects of temperature and precipitation indices are regional; these zones are differently affected by climate indices. Yearly climatic variability has created adverse conditions; However, in some zones, these impacts are negligible; Iran is in the exposure of relatively dry climate with hot summers and cold winters, and extreme temperatures annual events and irregular rainfall changes over the past years have made these farmers more resilient and adaptable.

Rural areas and their livelihoods directly related to the arid and semi-arid climatic variables. Natural hazards such as drought and water resource crisis in relation to climate change and climate variability in recent years have increased in the south of the province, including Nehbandan. This is especially the livelihoods and living conditions of the rural poor and vulnerable and small farming had a negative impact. The present study seeks to explore local perceptions and an insight about their livelihood strategies adopted in arid areas is Nehbandan.Methods was conducted in two parts, the first long-term According to the synoptic stations and climatology (2015-1980) the frequency of climatic risks in the area was zoned GIS environment, then according to the state of economic, social and environmental measures to prepare the questionnaire for the villagers' perceptions of climate change and adaptation strategies were discussed. Results showed that the consequences of climate change in South Khorasan respectively, drought, dust, floods and freezing is that spatial to differences.90 percent of respondents with regard to variables such as the increase in hot days, the frequency of droughts, declining rainfall and believe that the new situation in the climate of the region has occurred.87% of respondents have attempted to adapt to these conditions. The most important economic reaction respondents sale of livestock, borrow and borrow from relatives, reduce the cultivation and use of agricultural inputs and selecting new business and immigration. Environmental reactions can be resistant to change culture or ship new situation, the Bandsar and save water. Create new businesses that are less dependent on nature as a new approach to coping with climate change and reducing vulnerability and improving livelihoods in the region have been proposed.

A dust storm is a common phenomenon in many parts of the world, especially in arid and semiarid regions of the world. Dust storm adverse effects on the agriculture production and gardening, pollution of water and soil resources, a variety of respiratory diseases and the finally on the environmental issues, social challenges, a sharp reduction in horizontal visibility and road accidents. In this research, dust source identification in the Middle East with using MODIS satellite images was used in the period of time 2004-2014. For dust source identification 4 indices BTD3132 4BTD2931 4NDDI and D for 45 MODIS satellite images were calculated. Then with make a false-color combination (FCC) determined the best of a method dust source identification. The results showed that color combination BTD2931 4 B4 and B3 determined the best color combination for enhancement dust and dust source identification. The results showed that 212 points dust source identified in the case study that 123 points were in Iran and 93 Points in out of the country. The results also show that after Iran, Afghanistan has highest points dust source in the study area. The Middle East arid and semi-arid climates and precipitation in this area rarely exceed 300 mm per year As a result; this area has been poor vegetation cover and precipitation hardening and is susceptible to erosion.