نتایج جستجو برای: it causes soil moisture shortage and reduced current waters

تعداد نتایج: 17047266  

2006
A. J. Teuling P. A. Troch

Root zone soil moisture is a key variable in many land surface hydrology models. Often, however, there is a mismatch in the spatial scales at which models simulate soil moisture and at which soil moisture is observed. This complicates model validation. The increased availability of detailed datasets on space-time variability of root-zone soil moisture allows for a posteriori analysis of the unc...

Journal: :Remote Sensing 2017
Xuefei Zhang Tingting Zhang Ping Zhou Yun Shao Shan Gao

Soil moisture products acquired from passive satellite missions have been widely applied in environmental processes. A primary challenge for the use of soil moisture products from passive sensors is their reliability. It is crucial to evaluate the reliability of those products before they can be routinely used at a global scale. In this paper, we evaluated the Soil Moisture Active/Passive (SMAP...

Journal: :Remote Sensing 2010
Soo-See Chai Jeffrey P. Walker Oleg Makarynskyy Michael Kuhn Bert Veenendaal Geoff A. W. West

Passive microwave remote sensing is one of the most promising techniques for soil moisture retrieval. However, the inversion of soil moisture from brightness temperature observations is not straightforward, as it is influenced by numerous factors such as surface roughness, vegetation cover, and soil texture. Moreover, the relationship between brightness temperature, soil moisture and the factor...

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...

Journal: Journal of Nuts 2016
A. Alizadeh, H. Ansari N.. Sedaghati S. J. Hosseinifard

In this study, changes in soil moisture and salinity contents in drip irrigation combined with white and black plastic mulches compared to no mulch (control) was evaluated. The experiment was carried out in two commercial pistachio orchards (Ohadi cultivar) with irrigation frequencies of 8 to 12 days with a total water consumption 4100 and 6170 m3ha−1. The study was conducted in a complete rand...

2003
G. C. Van Kooten

Rates of soil erosion in the dryland cropping region of Saskatchewan are investigated under alternative cropping strategies. Chemical fallow is examined as an alternative to tillage fallow for moisture and soil conservation. Conclusions include: (a) flexible cropping increases net discounted returns and substantially reduces soil erosion compared to the predominant crop rotation; (b) chemical f...

2015
Ranmalee Bandara Jeffrey P. Walker Christoph Rüdiger Olivier Merlin

Soil moisture plays a key role in most environmental processes, as evaporation and transpiration are heavily dependent on soil moisture variability. While it is one of the few important hydrological variables that can be directly observed, the high spatial and temporal variability makes it difficult to measure globally or even regionally. Reliance is therefore placed on land surface models to p...

2004
Jeffrey P. Walker Paul R. Houser

Soil moisture satellite mission accuracy, repeat time and spatial resolution requirements are addressed through a numerical twin data assimilation study. Simulated soil moisture profile retrievals were made by assimilating near-surface soil moisture observations with various accuracy (0, 1, 2, 3, 4, 5 and 10%v/v standard deviation) repeat time (1, 2, 3, 5, 10, 15, 20 and 30 days), and spatial r...

2010
E. De Keyser H. Lievens H. Vernieuwe J. Álvarez-Mozos B. De Baets

Soil moisture retrieval from SAR images using semi-empirical or physically-based backscatter models requires surface roughness parameters, generally obtained by means of in situ measurements. However, measured roughness parameters often result in inaccurate soil moisture contents. Furthermore, when these retrieved soil moisture contents need to be used in data assimilation schemes, it is import...

The relationship between topography, land use, and topsoil moisture storage is investigated for a small catchment with undulating deep loess hilslopes in the south of the Netherlands. For a period of 10 months, soil moisture profiles have been measured weekly at 15 locations throughout the catchment. A Generalized Additive Model was employed to find relationships between the various factors inf...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید