جستجوی مقالات مرتبط با کلیدواژه « curvature » در نشریات گروه « جغرافیا »

 Erosion is a critical geomorphological process with significant environmental implications, including land degradation, fertility loss, and negative effects on aquatic ecosystems. It is recognized as an environmental hazard due to the substantial damages it can cause.

 This research uses geomorphometric indicators and a fuzzy approach to zoning the soil erosion potential in the Khiavchai area of Meshginshahr. Various variables were used, including slope, aspect, surface curvature, range length, Melton's roughness coefficient, stream power index, drainage density, topographic wetness index, distance from the river, vegetation, precipitation, and geological formations. The information layers were combined based on their impact on erosion using different fuzzifier functions. The fuzzy gamma operator in a GIS platform was utilized to combine and overlay the indicators. 

 The results revealed that approximately 8.4% of the study area exhibited high erosion potential. In comparison, around 18.7% had a high erosion potential, primarily located in the middle parts of the watershed. The high erodibility in these areas can be attributed to erodible geological formations, steep slopes, and high drainage density. Other contributing factors include predominantly southern and western slope aspects, longer slopes, and poor vegetation. 

 The indicators used in assessing erosion-prone areas provide insights into the geomorphological and hydrological conditions of the study watershed. The prepared erosion map can serve as a foundation for prioritizing soil conservation management measures and reducing the impact of erosion. 

Innovation:

 This research employs a combination of geomorphometric indicators and a fuzzy approach to assess soil erosion potential accurately. The practical application lies in utilizing the study's findings to prioritize areas for effectively implementing erosion mitigation and soil conservation measures in land management.

Analysis of the Properties of the earth's surface, which can be influenced by climatic, hydrological, intrinsic properties of formations and neotectonic activities, plays an important role in recognizing the physical Properties of the Watershed. On the other hand, understanding the physical Properties of the Watershed is one of the first steps required in morphological and hydrological studies. This research tries to study the shape of the earth's surface in Fahliyan watershed using morphometric indices. For this purpose, 6 geomorphometric indices, total curvature, profile curvature, surface curvature, TRI index, TPI index and TWI index were selected and using the relationships for each index and using relevant extensions in ArcGis 10/3 software, each map These indicators were prepared. The results of calculating the total curvature show that more than half of the surface of the basin (52.80) has a concave curvature and 47.20 percent of it has convex curvature. Also, the lower and upper limits for curvature of the surface were -2.99 and 3.96 respectively and for the curvature of the profile were -4.87 and 4.2 respectively. Accordingly, the lower and upper limit of the TPI index, which divides the mode of nodule and bulge, was calculated as <-4.2 and >, respectively. The values of the TRI index, which are somewhat different from the height of one pixel with their adjacent eight pixels, were calculated from 0 to >14. And finally TWI index values that indicate the soil moisture condition in the order of <-1.5 to >5.5 calculated. The percentage of the area of each of these indicators in the Watershed, which was obtained in the results of this study, can be used in various watershed planning including erosion and sediment, Landform Classifcation, identifying and introducing areas involved with landslide hazard, flood studies, studying and studying resources Groundwater and… to be used.

Karst is a set of geological processes and phenomena resulting from the dissolution of rocks . It is characterized by forming’s and Openings, erosion of formations and conditions of the stones, a specific type of water circulation , a certain type of local topography and the special regime of drainage network. Karst outcomes usually categorized as surface, subsurface and bathetic or internal complications.formation of Karsty phenomena such as karst pits, caves, Pole, graik and great fountains are As a result of secondary porosity.( Floria, 2005) Karst sinkholes are known as a karst erosion landforms and a proper criterion to identify Environment conditions in different periods. (pike,2011) Given the importance of Karst sinkholes, identifying and mapping distribution of karst sinkholes and their characteristics of forms are the needings of the Environmental science and geomorphology.( Van.Beynen ,,2011) Landforms are representing the processes that affect the Earth surface in the past and present and provide important informations about The characteristics and potentials of the Earth.( Bates,1987) quantitative and numerical geomorphology studies, spatial and statistical features and the correlation of spot features. also the basic principles that Geomorphomety emphasizes on that is the relationship between the form of roughness and it’s numerical parameters for explaining Processes that are involved in the formation and evolution of landforms. Kermanshah plain with an area of 5/739 km2 is located on the west side between 34 ° and 8 minutes and 32 seconds to 34° and 33 minutes and 52 seconds of north latitude and 46 degrees 22 minutes and 54 seconds to 47 degrees 00 minutes 31 seconds of East longitude from the Greenwich meridian and an average height of 1410 meters above sea level.

The basis of the identification and classification of landforms is based on Geomorphomety .Geomorphomety is about the quantity of the primary elements of morphology of the land such as slope, Slope orientation, height and relative height difference between elements, the elements relative location to each other, the condition of drainage network and Convexity or concavity of the elements.(Dehn,2001) Input data in the Geomorphomety studies is the digital model of height in Raster form and with square cells that In some cases the digital model of Earth surface could be replaced with it.( Mull,2002) In this research in order to identify the quantitative characteristics of the sinkholes in the region of Kermanshah Plain Geomorphomety indices including second grade derivatives of RTP index , indices of curvaturas parameters and finally sinkholes clustering are used. Important Curvaturas parameters including curved slope parameters (the amount of tilt in all directions), curvature profiles (at all levels) and the curvature of the plan (at all levels). Calculation of all types of curvature in digital model of raster elevation is pixel by pixel and for each cell a quartic poly-Tamyal equation is used (Equation 1 and 2)(Bishop,2000): 1) Z=Ax2y2 +Bx2y+Cxy2+Dx2+Ey2+Fxy+Hy+1 2) (SD – min D) / (max D-min D) To extract geo-morpho-metric indicators of Kermanshah Plain of digital elevation model with a resolution of 10 m, 1: 25,000 Topographic maps of mapping organization prepared and used for Geomorphometric analyzes .in order to evaluate the quantitatively landforms formation 55 units (sinkholes) were identified. Input data In the first phase are slope layer, sinkholes layer and DEM, which after entering each layer to zonal statistic as table command tables obtained. After extraction of Geomorphomety indices, average values and The maximum and minimum for each class, landforms obtained. Finally cluster analysis and output maps obtained from average data.

Kermanshah plain with elongation morphology, along the North - South, is among a collection of mountain and is limited from the north side to praw-bistoon mountains and from the south to White Mountains. In this region There are various forms of karst area from different landscapes such as sinkholes with enormous distribution. In order to existance of superelevation praw (bistoon and white mountains) in northern and southern regions of Kermanshah Plain, sinkholes affected fold and thrust belt, faults and breakage impact . based on the results we've achieved Sinkholes formations are simple, compound and complex.the role of faults is Dominant in the formation of Sinkholes in this region. The results of the rtp index represents this.the length of a small number of curvature sinkholes (11%) somewhat softened and in areas away from the fault in the lowlands has a softer morphology compared with heights which have jagged and rough morphology. Results of curvature index represents that curvature slope index,profile and plan have more performance in indicating the morphometery features of landslipy Sinkholes. based on the final clustering 89 percent of our sinkholes located on a main cluster And fault factors (tectonic) causes the formation of sinkholes on the heights and In terms of of the genesis and morphometric features they are the same (rugged and rough topography) and there is no dramatic difference between them.