نتایج جستجو برای: soil moisture retention curve

تعداد نتایج: 395269  

2013
B. Chrisman

Soil moisture governs the surface fluxes of mass and energy and is a major influence on floods and drought. Existing techniques measure soil moisture either at a point or over a large area many kilometers across. To bridge these two scales we used the cosmic-ray rover, an instrument similar to the recently developed COSMOS probe, but bigger and mobile. This paper explores the challenges and opp...

2012
SallyRose Anderson Glenn Tootle Henri Grissino-Mayer

Soil moisture is an important factor in the global hydrologic cycle, but existing reconstructions of historic soil moisture are limited. We used tree-ring chronologies to reconstruct annual soil moisture in the Upper Colorado River Basin (UCRB). Gridded soil moisture data were spatially regionalized using principal components analysis and k-nearest neighbor techniques. We correlated moisture se...

2013
S. Manfreda L. Brocca T. Moramarco M. Fiorentino

In the present work, we present a new formulation for the estimation of the soil moisture in the root zone based on the measured value of soil moisture at the surface. The method sheds lights on the relationship between surface and root zone soil moisture. It derives from a simplified form of the soil water balance equation and provides a closed form of the relationship between the root zone an...

ژورنال: علوم آب و خاک 2012
حجت امامی, , محمدرضا نیشابوری, , مهدی شرفا, ,

Direct measurement of soil unsaturated hydraulic conductivity (K(h) or K(θ)) is difficult and time-consuming, and often in many applied models, predicting hydraulic conductivity is carried out according to measurements of soil retention curve and saturated hydraulic conductivity (Ks). However, using KS as a matching point in many procedures may result in over-estimation of unsaturated hydraulic...

2009
Claire Gruhier François Cabot Yann Kerr Patricia de Rosnay Edouard Belin

Soil moisture is one of the most important variables that influences the soil-vegetation-atmosphere fluxes. This is particularly true over the Sahelian region, soil moisture has an important feedback on precipitation. It is particularly difficult to access to soil moisture values because its high temporal and spatial variability. Different approaches exist, but microwave remote sensing is the m...

2010
Fuqin Li Wade T. Crow William P. Kustas

The upcoming deployment of satellite-based microwave sensors designed specifically to retrieve surface soil moisture represents an important milestone in efforts to develop hydrologic applications for remote sensing observations. However, typical measurement depths of microwave-based soil moisture retrievals are generally considered too shallow (top 2–5 cm of the soil column) for many important...

2003
Jun Wen Zhongbo Su

[1] The radar backscattering coefficient is mainly determined by surface soil moisture, vegetation and land surface roughness under a given configuration of the satellite sensor. It is observed that the temporal variations of the three variables are different, the variation of vegetation and roughness are at the longer temporal scales corresponding to climate and cultivation practices, while so...

2007
Haibin Li Alan Robock Martin Wild

[1] Soil moisture trends, particularly during the growing season, are an important possible consequence of global warming. Climate model simulations of future soil moisture changes should be made with models that can produce reliable simulations of soil moisture for past climate changes. In this paper, we compare soil moisture simulations from Intergovernmental Panel on Climate Change Fourth As...

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