نتایج جستجو برای: because soil moisture condition affects vegetation changes hence

تعداد نتایج: 2151105  

2008
Genxu Wang Yuanshou Li Hongchang Hu Yibo Wang

Seasonal changes over 2 years (2004–2006) in soil moisture content ( v) of frozen alpine frost meadow soils of the QinghaiTibet plateau permafrost region under three different levels of vegetation cover were investigated. Vegetation cover and air temperature changes had significant effects (synergistic effect) on v and its distribution in the soil profile. During periods of soil freezing or tha...

2011
Mario A. Giraldo Sara Gale

Soil moisture is a critical process in the water cycle and its assessment is of paramount importance to forecast changes in the water balance of a region. Ground Penetrating Radar (GPR) technology overcomes the limitations of point data by producing a tridimensional view of subsurface characteristics with a large economy of time, logistic, data processing and analysis. The purpose of this resea...

2015
Martine Marije RUTTEN

The boundary that separates the earth from the atmosphere is a crucial zone of study for meteorology and hydrology. Here, solar energy is partitioned into sensible heat which drives atmospheric circulation, latent heat needed for evaporation from the soil and transpiration of vegetation, and soil heat which warms the subsurface. Precipitation is partitioned into interception that evaporates dir...

Recognition of humidity changes is important because of its relevance to hydrological, ecological and physiographic characteristics of the area. Therefore, soil moisture content in four main directions and three depths of 50, 70 and 110 cm of soil for two years from March 2013 to September 2012 in the forest area of Meleh-Siah Ilam was measured and analyzed in a randomized complete block design...

2014
Yuteng Ma Remke L. Van Dam Dushmantha H. Jayawickreme

In deciduous forests, soil moisture is an important driver of numerous physical, microbial, and biogeochemical processes. Therefore, characterizing the interactions between vegetation and soil moisture is critical to forecast long-term water resources and ecosystem health. However, these interactions are difficult to measure, both in time and space. Recent studies have shown the ability of elec...

2002
F. Del Frate P. Ferrazzoli G. Schiavon

Two neural network algorithms trained by a physical vegetation model are used to retrieve soil moisture and vegetation variables of wheat canopies during the whole crop cycle. The first algorithm retrieves soil moisture using L band, two polarizations and multiangular radiometric data, for each single date of radiometric acquisition. The algorithm includes roughness and vegetation effects, but ...

2008
Enrique R. Vivoni Mekonnen Gebremichael Christopher J. Watts Rajat Bindlish Thomas J. Jackson

Comparisons to ground-based surface soil moisture estimates are necessary to evaluate the capability of remote sensors to determine soil moisture and its spatiotemporal variability. Soil moisture can be especially variable in regions of complex terrain which exhibit large variations in vegetation, soil properties and hydrologic conditions. The objective of this study is to evaluate the spatiote...

2010
M. Ebrahimi A. A. Matkan

Rainfall, soil moisture, increasing temperature and changes in vegetation cover are the most important parameters effecting drought. Therefore, analysis of vegetation fraction and soil spectral signature, especially in red and infra red bands, are essential in drought estimation using remote sensing. In this study, Modified Perpendicular Drought Index (MPDI), which uses Vegetation Fraction (VF)...

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...

2015
Franco Catalano Andrea Alessandri Matteo De Felice Zaichun Zhu Ranga B. Myneni

The temporal variance of soil moisture, vegetation and evapotranspiration over land has been recognized to be strongly connected to the temporal variance of precipitation. However, the feedbacks and couplings between these variables are still not well understood and quantified. Furthermore, soil moisture and vegetation processes are associated with a memory and therefore they may have important...

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