نتایج جستجو برای: soil moisture

تعداد نتایج: 205538  

Journal: :Remote Sensing 2009
Tarendra Lakhankar Hosni Ghedira Marouane Temimi Manajit Sengupta Reza Khanbilvardi Reginald A. Blake

Satellite remote sensing observations have the potential for efficient and reliable mapping of spatial soil moisture distributions. However, soil moisture retrievals from microwave remote sensing techniques are typically complex due to inherent difficulty in characterizing the interactions among land surface parameters that contribute to the retrieval process. Therefore, adequate physical mathe...

2004
ROLF H. REICHLE RANDAL D. KOSTER JIARUI DONG AARON A. BERG

Three independent surface soil moisture datasets for the period 1979–87 are compared: 1) global retrievals from the Scanning Multichannel Microwave Radiometer (SMMR), 2) global soil moisture derived from observed meteorological forcing using the NASA Catchment Land Surface Model, and 3) ground-based measurements in Eurasia and North America from the Global Soil Moisture Data Bank. Time-average ...

2006
Wenge Ni-Meister Paul R. Houser Jeffrey P. Walker

[1] Climate model prediction skill is currently limited in response to poor land surface soil moisture state initialization. However, initial soil moisture state prediction skill can potentially be enhanced by the assimilation of remotely sensed near-surface soil moisture data in off-line simulation. This study is one of the first to evaluate such potential using actual remote sensing data toge...

2011
Julien Minet Patrick Bogaert Marnik Vanclooster Sébastien Lambot

Ground penetrating radar (GPR) is an efficient method for soil moisture mapping at the field scale, bridging the scale gap between small-scale invasive sensors and large-scale remote sensing instruments. Nevertheless, commonly-used GPR approaches for soil moisture characterization suffer from several limitations and the determination of the uncertainties in GPR soil moisture sensing has been po...

2012
Wade T. Crow Aaron A. Berg Michael H. Cosh Alexander Loew Binayak P. Mohanty Rocco Panciera Patricia de Rosnay Dongryeol Ryu Jeffrey P. Walker

[1] The contrast between the point-scale nature of current ground-based soil moisture instrumentation and the ground resolution (typically >10 km) of satellites used to retrieve soil moisture poses a significant challenge for the validation of data products from current and upcoming soil moisture satellite missions. Given typical levels of observed spatial variability in soil moisture fields, t...

2013
Tana E. Wood Matteo Detto Whendee L. Silver

Precipitation and temperature are important drivers of soil respiration. The role of moisture and temperature are generally explored at seasonal or inter-annual timescales; however, significant variability also occurs on hourly to daily time-scales. We used small (1.54 m(2)), throughfall exclusion shelters to evaluate the role soil moisture and temperature as temporal controls on soil CO2 efflu...

Journal: :Remote Sensing 2017
Chenjie Xing Nengcheng Chen Xiang Zhang Jianya Gong

Surface soil moisture is an important environment variable that is dominant in a variety of research and application areas. Acquiring spatiotemporal continuous soil moisture observations is therefore of great importance. Weather conditions can contaminate optical remote sensing observations on soil moisture, and the absence of remote sensors causes gaps in regional soil moisture observation tim...

2012
H. Mittelbach

Knowledge about the spatio-temporal variability of soil moisture is essential to understand and predict processes in climate science and hydrology. A significant body of literature exists on the characterization of the spatial variability and the rank stability (also called temporal stability) of absolute soil moisture. Yet previous studies were generally based on short-term measurement campaig...

2003
M. SHOSHANY T. SVORAY P. J. CURRAN G. M. FOODY A. PEREVOLOTSKY

A linear relationship between ERS-2 SAR backscattering coe cient (s0 ) and volumetric soil moisture was determined at both ends of a rainfall gradient in Israel. A Normalized radar Backscatter soil Moisture Index (NBMI) was derived and related strongly to soil moisture concentration. This index may allow the mapping of soil moisture conditions over large areas with C band SAR data.

2002
Jeffrey P. Walker

of the spatial variability in soil moisture within the root zone. An instrument for making rapid measurements of the soil moisture Studies have shown that soil moisture content can content in the root zone is an essential tool for many applications, be inferred from measurements of the soil electrical including understanding of soil water dynamics, evaluation of agriculresistance (e.g., Seyfrie...

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