نتایج جستجو برای: desertification indices

تعداد نتایج: 84578  

Journal: :مرتع و آبخیزداری 0
الهام السادات شکوهی دانش آموخته کارشناس ارشد مدیریت مناطق بیابانی، دانشکده منابع طبیعی، دانشگاه تهران، ایران. غلامرضا زهتابیان استاد دانشکده منابع طبیعی، دانشگاه تهران، ایران. علی طویلی دانشیار دانشکده منابع طبیعی، دانشگاه تهران، ایران.

more than 80% of iran’s area has arid and semi arid climate. therefore, iran is exposed to desertification process. practical activities in controlling desertification must be based on current desertification situation and its severity. based on this theory, evaluating desertification rate indices in khezrabad region was done based on imdpa model. in this research two factors with 10 indices we...

Journal: :desert 0
m.h. sadeghi ravesh assistant professor, faculty of agriculture, islamic azad university, takestan branch, takestan, iran h. ahmadi professor, islamic azad university, science and research branch, tehran, iran gh.r. zehtabian professor, faculty of natural resources, university of tehran, karaj, iran m. tahmoures phd. student, faculty of natural resources, university of tehran, karaj, iran

due to increasing importance of desertification challenges and its consequences the necessity of sustainabledevelopment achievement in arid and semi-arid regions is essential in order to avoid limited sources asting, increase the efficiency of controlling, reclamation and restoration projects of natural areas. based on the iterature review, it has been recognized that combating desertification ...

Journal: :desert 2013
m.h. sadeghi ravesh h. ahmadi gh.r. zehtabian m. tahmoures

due to increasing importance of desertification challenges and its consequences the necessity of sustainabledevelopment achievement in arid and semi-arid regions is essential in order to avoid limited sources asting, increase the efficiency of controlling, reclamation and restoration projects of natural areas. based on the iterature review, it has been recognized that combating desertification ...

Journal: :desert 2008
f. taghavia h. mohammadi

climate is the most important factor which control desertification .in order to detect climate changes in desert zones, time trend analysis is applied to extreme indices in kashan station using extreme climate index software (ecis). results show significant trends in extreme indices during the past decade 1995-2004 and the pronounced warming is associated with a negative trend in cold extremes....

Journal: :Int. J. Applied Earth Observation and Geoinformation 2014
Xia Zhang Kun Shang Yi Cen Tong Shuai Yanli Sun

Coverage rates of vegetation and exposed bedrock are two key indicators of karst rocky desertification. In this study, the abundances of vegetation and exposed rock were retrieved from a hyperspectral Hyperion image using linear spectral unmixing method. The results were verified using the spectral indices of karst rocky desertification (KRDSI) and an integrated LAI spectral index: modified chl...

ژورنال: علوم آب و خاک 2015
جعفری, رضا, سلطانی, سعید, فتحی, محبوبه,

Desertification is known as a major crisis in arid regions of Isfahan province. This study aimed to assess the performance of three main desertification models including MEDALUS, MICD and FAO-UNEP for mapping desertification severity in the hotspot of Jarghuyeh region, eastern Isfahan. Different desertification indicators and their related indices were chosen based on the characteristics of the...

Journal: Desert 2012
Gh.R. Zehtabian H. Ahmadi M. Tahmoures M.H. Sadeghi Ravesh

Due to increasing importance of desertification challenges and its consequences the necessity of sustainabledevelopment achievement in arid and semi-arid regions is essential in order to avoid limited sources asting, increase the efficiency of controlling, reclamation and restoration projects of natural areas. Based on the iterature review, it has been recognized that combating desertification ...

ژورنال: علوم آب و خاک 2018

In this study, to study the status of water resources degradation in Kashan region, Isfahan Province, eight indices including: drop in groundwater, water salinity, irrigation efficiency, Well-to-Qanat development ratio, the pumping time, shortage of water supplies for animals and humans and the water negative balance were selected according to previous studies conducted on desertification in Ir...

Journal: :desert 2005
gh. r. zehtabian h. ahmadi h. khosravi a. rafiei emam

desertification process as a great problem affects most of the countries in the world specially developing countries. this process has a high rate in arid and semi-arid countries such as iran. the main objective of this research was to investigate land degradation status and desertification mapping of kashan area. different studies have been carried out in the world in order to assess desertifi...

Journal: Desert 2008
F. Taghavia H. Mohammadi,

Climate is the most important factor which control desertification .In order to detect climate changes in desert zones, time trend analysis is applied to extreme indices in Kashan station using extreme climate index software (ECIS). Results show significant trends in extreme indices during the past decade 1995-2004 and the pronounced warming is associated with a negative trend in cold extremes....

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