نتایج جستجو برای: wind water erosion crisscross region

تعداد نتایج: 1150573  

Introduction: More than 168 countries face the phenomenon of land degradation and desertification. Land use changing and more exploitation of nature's potential in arid and semiarid ecosystems over the past three decades have increased the trend of desertification phenomena in these ecosystems. Deserts are dynamic ecosystems that are constantly evolving. Deserts are dynamic ecosystems that are ...

2014
Zhongling Guo Ning Huang Zhibao Dong Robert Scott Van Pelt Ted M. Zobeck Douglas L. Karlen Marc A. Rosen

Soil degradation is one of the most serious ecological problems in the world. In arid and semi-arid northern China, soil degradation predominantly arises from wind erosion. Trends in soil degradation caused by wind erosion in northern China frequently change with human activities and climatic change. To decrease soil loss by wind erosion and enhance local ecosystems, the Chinese government has ...

2008
A. MAXWELL

Darlit streamlined streaks observed in orbital images of the Western Desert of Egypt are similar in saale and form to craterand knob-related streaks on the martian surfaae. In Egypt, dark streaks form in the lee of topographic highs^ ranging in sise from small hills a few meters across^ to the 60 km wide Uweinat massifs On the surfaae of Mars, streaks may he either lighter or darker in tone tha...

2010
Sujith Ravi David D. Breshears Travis E. Huxman Paolo D'Odorico

a r t i c l e i n f o Land degradation in drylands is one of the major environmental issues of the 21st century particularly due to its impact on world food security and environmental quality. Climate change, shifts in vegetation composition, accelerated soil erosion processes, and disturbances have rendered these landscapes susceptible to rapid degradation that has important feedbacks on regio...

Journal: :تحقیقات جغرافیایی 0
عادل سپهر دانشکده منابع طبیعی و محیط زیست، دانشگاه فردوسی مشهد

monte carlo methods designed base on stochastic reiterations and can be useful in uncertainty conditions. the purpose of this research was investigation of uncertainty to rank desertification indicators. in order to decrease uncertainty have been applied monte carlo reiterations for each value of indicator, if rank of xi is higher than rank of xk constantly. using multi dimension integrals the ...

2012
Liu Xuedong Liu Zhiyan

When the crisscross baffles and logarithmic spiral baffles are placed on the bottom of the stirred tank with elliptic bottom, using CFD software FLUENT simulates the velocity field of the stirred tank with elliptic bottom and bottom baffles. Compare the velocity field of stirred tank with bottom crisscross baffle to the velocity field of stirred tank without bottom baffle and analysis the flow ...

Journal: :Appl. Math. Lett. 2015
Luigi Preziosi Davide Fransos Luca Bruno

Three phenomena are involved in sand movement: erosion, wind transport, and sedimentation. This paper presents a comprehensive easy-to-use multiphase model that include all three aspects with a particular attention to situations in which erosion due to wind shear and sedimentation due to gravity are not in equilibrium. The interest is related to the fact that these are the situations leading to...

Journal: :desert 2012
h r azimzadeh m r ekhtesasi

different types of sediment trap have been introduced so far to be used in erosion measuring stations, each with its own advantages and disadvantages in trapping aeolian particles. these traps have different collection and retention efficiency due to aerodynamic conditions. some characteristics such as isokinetic feature of the trap, collection efficiency, time needed to download sediment, capa...

Journal: :Sustainability 2022

Land degradation induced by soil erosion is widespread in semiarid regions globally and common the agro–pastoral ecotone of northern China. Most researchers identify wind water as independent processes, there a lack research regarding relative contributions interactions between them what referred to here compound (CSE). CSE may occur situations where more effectively erodes surface already subj...

Behnoush Farokhzadeh Davoud Akhzari, Iman Saeedi Mohsen Goodarzi

Dust storms are known as hazardous problems in western part of Iran. Iraq is one of the main sources for dust storm arriving to the western part of Iran. The Radial Basis Function Network model (RBFN) has been used to assess wind erosion hazards in the source area of dust storms over several western Iranian cities. Normalized Difference Salinity Index (NDSI) was used to determine the changes in...

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