نتایج جستجو برای: deforestation and desertification
تعداد نتایج: 16827997 فیلتر نتایج به سال:
Understanding how desertification takes place in different ecosystems is an important step in attempting to forecast and prevent such transitions. Dryland ecosystems often exhibit patchy vegetation, which has been shown to be an important factor on the possible regime shifts that occur in arid regions in several model studies. In particular, both gradual shifts that occur by front propagation, ...
Exploitation of fuel wood in pre-colonial Africa did not affect ecological balance. Carbon generated was sunk into living trees in exchange for oxygen. However, the coming of colonialism, industrial revolution, introduction of scientific or industrial forestry and urbanization has substantially altered the balance between exploitation and forest sustainability. The impact of fuel wood exploitat...
Tongyu County in Northeast China is highly prone to land degradation due to its fragile physical settings characterized by a flat topography, a semi-arid climate, and a shallow groundwater table. This study aims to determine the causes of land degradation through detecting the long-term trend of land cover changes. Degraded lands were mapped from satellite images recorded in 1992 and 2002. Thes...
Summary Precisely detecting land cover changes aids in improving the analysis of dynamics landscape and plays an essential role mitigating effects desertification. Mainly, sensing desertification is challenging due to high correlation between like‐desertification events (e.g., deforestation). An efficient flexible deep learning approach introduced address detection through Landsat imagery. Esse...
The link between environmental degradation and international security has attracted new attention due to the publication of the United Nations report A More Secure World: Our Shared Responsibility, authored by the High Level Panel on Threats, Challenges and Change, a group of experts assembled by Kofi Annan and tasked with advising the Security Council about new global threats. The panel specif...
The focus of this paper is the role of meridional distribution of vegetation in the dynamics of monsoons and rainfall over West Africa. A moist zonally symmetric atmospheric model coupled with a simple land surface scheme is developed to investigate these processes. Four primary experiments have been carried out to examine the sensitivity of West African monsoons to perturbations in the meridio...
OCTOBER 2004 AMERICAN METEOROLOGICAL SOCIETY | A erosols are airborne suspensions of tiny particles, each typically about one-thousandth the diameter of the period at the end of this sentence. Cumulatively, they have profound effects at a variety of scales, exerting myriad influences on the earth’s environment and climate and on human health. Many aerosols originate from natural sources—volcano...
OCTOBER 2004 AMERICAN METEOROLOGICAL SOCIETY | A erosols are airborne suspensions of tiny particles, each typically about one-thousandth the diameter of the period at the end of this sentence. Cumulatively, they have profound effects at a variety of scales, exerting myriad influences on the earth’s environment and climate and on human health. Many aerosols originate from natural sources—volcano...
Desertification in north China is ongoing despite the endeavours to mitigate it over the past 50 years. Overall examination of the context of desertification and defects of desertification-combating programmes is a prerequisite for desertification control, which is now attracting general concern in China. The physiographic circumstances of north China, including the dry, continental, mid-latitu...
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