نتایج جستجو برای: different vegetation

تعداد نتایج: 1800636  

Journal: :journal of agricultural science and technology 2014
m. masoudi

the entire land in the southern iran faces problems arising out of various types of land degradation, of which the vegetation type forms one of the major ones. the payab basin (522,470 ha), which covers the lower reaches of mond river, was chosen for a test risk assessment of this type. the different kinds of data for indicators of vegetation degradation were taken from the records and publishe...

Journal: :ecopersia 2011
ghasem ali dianati tilaki hossein naderi nasrabad jalal abdollahi

the relationship between topography, soil factors, and distribution of ecological vegetation groups in the nodoushan arid rangelands of yazd province (iran) was investigated. the present species were recorded in each vegetation group using a randomized-systematic sampling method. plant cover and density were estimated quantitatively using the transect and quadrate methods, and the two-way indic...

2016
Zhiyong Liu Chao Li Ping Zhou Xiuzhi Chen

Climate change significantly impacts the vegetation growth and terrestrial ecosystems. Using satellite remote sensing observations, here we focus on investigating vegetation dynamics and the likelihood of vegetation-related drought under varying climate conditions across China. We first compare temporal trends of Normalized Difference Vegetation Index (NDVI) and climatic variables over China. W...

2008
M. Baudena

We discuss a simplifed, conceptual model for the dynamics of the soil-vegetation system in drylands. The model considers the different dynamical processes taking place in vegetated and non-vegetated soil and it distinguishes between the upper soil layer, where rapid evaporation dominates, and the deeper root layer where only plant transpiration takes place. We explore the role of rainfall inter...

2006
T. Wagner

Introduction Conclusions References Tables Figures Back Close Full Screen / Esc Printer-friendly Version Interactive Discussion EGU Abstract A new method for the satellite remote sensing of different types of vegetation and ocean colour is presented. In contrast to existing algorithms, our method analyses weak narrow-band reflectance structures (i.e. " fingerprint " structures) of vegetation in...

2014
Gaolong Zhu Weimin Ju J. M. Chen Yibo Liu

A new moisture adjusted vegetation index (MAVI) is proposed using the red, near infrared, and shortwave infrared (SWIR) reflectance in band-ratio form in this paper. The effectiveness of MAVI in retrieving leaf area index (LAI) is investigated using Landsat-5 data and field LAI measurements in two forest and two grassland areas. The ability of MAVI to retrieve forest LAI under different backgro...

2003
E. Jeppesen

The turbidity of lakes is generally considered to be a smooth function of their nutrient status. However, recent results suggest that over a range of nutrient concentrations, shallow l&es can have two alternative equilibria: a clear state dominated by nquatic vegetation, and a turbid state characterized by high algal biomass. This bi-stability has important implications for the possibilities of...

2007
A. Kleidon

Multiple steady states in the atmospherebiosphere system can arise as a consequence of interactions and positive feedbacks. While atmospheric conditions affect vegetation productivity in terms of available light, water, and heat, different levels of vegetation productivity can result in differing energyand water partitioning at the land surface, thereby leading to different atmospheric conditio...

2007
Toon Westra Sarah Crabbe

The Waza-Logone floodplain in the north of Cameroon is both ecologically and economically of exceptional importance. Envisat ASAR Alternating Polarization images are used for studying the flooded grassland vegetation. Backscatter signature of different vegetation types, varying in species composition, height, density, and flooding condition, were analyzed and interpreted. Feature selection base...

2016
Siyuan Wang Bojuan Yang Qichun Yang Linlin Lu Xiaoyue Wang Yaoyao Peng

Satellite-derived vegetation phenology has been recognized as a key indicator for detecting changes in the terrestrial biosphere in response to global climate change. However, multi-decadal changes and spatial variation of vegetation phenology over the Northern Hemisphere and their relationship to climate change have not yet been fully investigated. In this article, we investigated the spatial ...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید