نتایج جستجو برای: loess
تعداد نتایج: 3659 فیلتر نتایج به سال:
a r t i c l e i n f o Eco-economic regionalization (EER) is to divide an area into geographical zones. Each zone is linked to the others based on the eco-economic similarity and disparity. In this study, models of EER of the Chinese Loess Plateau were constructed. Data on 22 selected indicators were gathered for the 282 administrative counties. Then they were analyzed through an approach of PCA...
Evapotranspiration (ET) is an important component of the surface energy balance and hydrological cycle. In this study, the eddy covariance technique was used to measure ET of the semi-arid farmland ecosystem in the Loess Plateau during 2010 growing season (April to September). The characteristics and environmental regulations of ET and crop coefficient (Kc) were investigated. The results showed...
Four new AMS 14C ages, glacial mapping, and measurements of soil development, loess thickness, and moraine morphology constrain the age and extent of at least three Quaternary advances by outlet lobes of an ice cap over the Ahklun Mountains of southwestern Alaska. The relative-age data are from 107 sites correlated to 25 ice-marginal positions in the Kanektok, Goodnews, Togiak, and Kulukak Rive...
The residence time of ice in permafrost is an indicator of past climate history, and of the resilience and vulnerability of high-latitude ecosystems to global change. Development of geochemical indicators of ground-ice residence times in permafrost will advance understanding of the circumstances and evidence of permafrost formation, preservation, and thaw in response to climate warming and othe...
This study presents a special problem on vertical distribution for sediment and copper in hyper-concentrated turbulent solid-liquid system that is essentially different from the ordinary low-concentrated turbulent system. A resonance type turbulent simulation equipment is used for the experimental study in which a vertically uniform turbulent field of the mixture of loess and water is produced ...
Quantifying the hydrologic responses to land use ⁄ land cover change and climate variability is essential for integrated sustainable watershed management in water limited regions such as the Loess Plateau in Northwestern China where an adaptive watershed management approach is being implemented. Traditional empirical modeling approach to quantifying the accumulated hydrologic effects of watersh...
BACKGROUND As a key strategy for mitigating global climate change, bioenergy production by reducing CO2 emissions plays an important role in ensuring sustainable development. However, land-use change by converting natural ecosystems into energy crop field could create a carbon debt at the beginning. Thus, the potential carbon debt calculation is necessary for determining a promising bioenergy c...
We discuss the history of exploration of Red Clay vertebrate fossils of the Loess Plateau, and record observations on “Hipparion Red Clay” localities of Shanxi and Gansu provinces. Red clay is widespread across the Loess Plateau, but misleading as a descriptive term because many deposits are neither red nor dominated by clay-size sediment. Many red clay sequences contain paleosols, but also wat...
A risk assessment of vegetation zone responses to climate change was conducted using the classical Holdridge life zone model on the Loess Plateau of Northwest China. The results show that there are currently ten vegetation zones occurring on the Loess Plateau (1950–2000), including alvar desert, alpine wet tundra, alpine rain tundra, boreal moist forest, boreal wet forest, cool temperate desert...
Land-use change is widely considered to be a major factor affecting soil carbon (C) sequestration (ΔCs). This paper studied changes to soil C stocks (Cs) following the conversion of farmland to forest, shrub and grassland across the key area for implementing China's "Grain for Green"--the Loess Plateau. The results are based on a synthesis of 44 recent publications (including 424 observations a...
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