نتایج جستجو برای: soil moisture curve

تعداد نتایج: 331640  

2014
Mohammad Subzar Malik

Understanding the spatial and temporal variations of soil moisture is crucial for the land surface processes and their management. Accurate estimation of spatial and temporal variations of soil moisture is important for various hydrological studies also. Recently, remote sensing techniques have been used to estimate soil moisture. Estimation of soil moisture by remote sensing techniques provide...

2010
Tarendra Lakhankar Andrew S. Jones Cynthia L. Combs Manajit Sengupta Thomas H. Vonder Haar Reza Khanbilvardi

Spatial and temporal soil moisture dynamics are critically needed to improve the parameterization for hydrological and meteorological modeling processes. This study evaluates the statistical spatial structure of large-scale observed and simulated estimates of soil moisture under pre- and post-precipitation event conditions. This large scale variability is a crucial in calibration and validation...

2007
Alexander Loew Heike Bach Wolfram Mauser

Soil moisture is a key variable for the water and energy exchanges at the land surface. The determination of soil moisture dynamics from space is one of the most prominent, but also most challenging applications for recent active microwave sensor systems. Since the launch of ENVISAT ASAR, more than 4 years of data is available for the retrieval of soil moisture information. The wide area covera...

2001
JEFFREY P. WALKER GARRY R. WILLGOOSE JETSE D. KALMA

The Kalman filter assimilation technique is applied to a simplified soil moisture model for retrieval of the soil moisture profile from near-surface soil moisture measurements. First, the simplified soil moisture model is developed, based on an approximation to the Buckingham–Darcy equation. This model is then used in a 12month one-dimensional field application, with updating at 1-, 5-, 10-, an...

2007
Tarendra Lakhankar Andrew Jones Cynthia Combs Dustin Rapp Thomas H. Vonder Haar

The spatial pattern of soil moisture varies at different scales due to evapo-transpiration and precipitation which are transformed by topography, soil texture, and vegetation. The mapping of soil moisture by remote sensing has several advantages over conventional field measurement techniques especially in the case of heterogeneous landscapes. However, validation of low resolution satellite soil...

2006
J. A. SMETHURST

In temperate European climates, the season of peak water demand by vegetation (summer) is out of phase with the season of greatest rainfall (winter). This results in seasonal fluctuations in soil water content and, in clay soils, associated problems of shrinking and swelling that can in turn contribute to strain-softening and progressive slope failure. This paper presents field measurements of ...

2009
Chunling Tang Thomas C. Piechota

This research investigates the interannual variability of soil moisture as related to large-scale climate variability and also evaluates the spatial and temporal variability of modeled deep layer (40–140 cm) soil moisture in the Upper Colorado River Basin (UCRB). A three layers hydrological model VIC-3L (Variable Infiltration Capacity Model – 3 layers) was used to generate soil moisture in the ...

2010
M. Choi H. Kim

Passive microwave sensors have many advantages including the ability to directly measured soil moisture at large spatial scales regardless of weather conditions or time of day. However, microwave-sensed soil moisture’s inevitable limitation is that it cannot describe hydrology at the watershed because its retrieved soil moisture scale is too large. Thus, microwave-sensed soil moisture requires ...

Journal: :Remote Sensing 2009
Claudia Notarnicola

This paper presents an approach denominated Group Inversion Approach (GIA) which aims at detecting soil moisture temporal invariants, i.e., the stable temporal soil moisture locations, by using mainly remotely sensed data. The soil moisture temporal invariants are those locations where independently of the absolute value changes, the relative spatial distribution of soil moisture remains almost...

2007
Feike A. Dijkstra Weixin Cheng

While it is well known that soil moisture directly affects microbial activity and soil organic matter (SOM) decomposition, it is unclear if the presence of plants alters these effects through rhizosphere processes. We studied soil moisture effects on SOM decomposition with and without sunflower and soybean. Plants were grown in two different soil types with soil moisture contents of 45% and 85%...

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