نتایج جستجو برای: soil moisture

تعداد نتایج: 205538  

2011
W. A. Dorigo W. Wagner

In situ measurements of soil moisture are invaluable for calibrating and validating land surface models and satellite-based soil moisture retrievals. In addition, longterm time series of in situ soil moisture measurements themselves can reveal trends in the water cycle related to climate or land cover change. Nevertheless, on a worldwide basis the number of meteorological networks and stations ...

2007
Xianwei Wang Hongjie Xie Huade Guan Xiaobing Zhou

r a 200 .022 : +1 210 [email protected] Summary Surface representation of the root-zone soil moisture is investigated so that feasibility of using optical remote sensing techniques to indirectly map root-zone soil moisture is assessed. Specifically, covariation of root-zone soil moisture with the normalized difference of vegetation index (NDVI) from Moderate Resolution Imaging Spectroradiometer (MODIS) ...

2016
J. L. Kong T. Xian J. Yang L. Chen X. T. Yang

The coal development zone of Northern Shaanxi, China is one of the eight largest coal mines in the world, also the national energy and chemical bases. However, the coal mining leads to ground surface deformation and previous studies show that in collapse fissure zone soil water losses almost 50% compared with non-fissure zone. The main objective of this study is to develop a retrieval model tha...

2016
Charles V. Privette Ahmad Khalilian William Bridges Stephen Katzberg Omar Torres Young J. Han Joe Mari Maja Xin Qiao C. V. Privette

Many agricultural fields across the country have a high degree of variability in soil type and water holding capacity that affects irrigation management. One way to overcome problems associated with the field variability for improving irrigation management is to utilize a site-specific irrigation system. This system applies water to match the needs of individual management zones within a field....

2010
Minha Choi Jennifer M. Jacobs

Soil moisture state and variability control many hydrological and ecological processes as well as exchanges of energy and water between the land surface and the atmosphere. However, its state and variability are poorly understood at spatial scales larger than the fields (i.e. 1 km2) as well as the ability to extrapolate field scale to larger spatial scales. This study investigates soil moisture...

2006
Willem W. Verstraeten Jan Feyen

Global carbon budget studies are currently dominated by temperature analysis since the importance of this meteorological variable on photosynthesis processes and soil carbon dynamics. Yet, the strong coupling between the carbon and hydrological cycles is a longstanding acquisition of the biogeophysical sciences. To take the important aspect of water limitation in carbon studies into account, wa...

2003
Yongkang Xue

In this paper, SSiB's development and some of its major parameterizations in the model are briefly reviewed. The soil moisture parameterizations, which are a key element in the model, are comprehensively described. The sensitivity study shows that hydraulic conductivity at saturation, B parameter, and wilting point have a profound impact on the simulation of soil moisture, hut with different fe...

2003
F. Portmann W. Wagner K. Scipal

The soil moisture content is of great importance for numerical weather forecasts and has been identified as one of the parameter products of EUMETSAT’s Satellite Application Facility on Land Surface Analysis (Land SAF). Soil moisture strongly affects the surface energy balance and therefore near surface temperature and humidity. Conversely, temperature observations may be used to infer the soil...

2003
Jeffrey P. Walker Paul R. Houser Garry R. Willgoose

Active microwave remote sensing observations of backscattering, such as C-band vertically polarized synthetic aperture radar (SAR) observations from the second European remote sensing (ERS-2) satellite, have the potential to measure moisture content in a near-surface layer of soil. However, SAR backscattering observations are highly dependent on topography, soil texture, surface roughness and s...

2012
M. Zreda W. J. Shuttleworth X. Zeng

The newly-developed cosmic-ray method for measuring area-average soil moisture at the hectometer horizontal scale is being implemented in the COsmic-ray Soil Moisture Observing System (or the COSMOS). The stationary cosmic-ray soil moisture probe measures the neutrons that are generated by cosmic rays within air and soil and other materials, moderated by mainly hydrogen atoms located primarily ...

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