Search results for "NDVI"

Impact de la variabilité climatique et de la dynamique des états de surface sur les écoulements du bassin béninois du fleuve Niger

2007

This thesis has for principal objective to establish a diagnosis of the hydrological system of the beninese basin of the Niger River, in the context of the rainfall decrease which has severely affected Africa since the 1970s. To achieve this goal, this study was based on three main types of data :weather (rainfall, temperature, relative humidity, potential evapotranspiration, real evapotranspiration), hydrological (stream flow, recharge) and of land surface conditions (land cover types, NDVI).It considers three key aspects. The first one, devoted to the study of hydro-climatic variability over the period 1955- 1992, shows that the rainfall deficits of the 1970s and 1980s were largely amplif…

Smiltāja neļķes (Dianthus arenarius) izplatības modelēšana pelēkajās kāpās izmantojot attālās izpētes datus

2016

Smiltāja neļķe (Dianthus arenarius) ir Latvijā reti sastopama, aizsargājama vaskulāro augu suga. Tās pasuga Dianthus arenariu subsp. arenarius ir aizsargājama visā Eiropas Savienības (ES) līmenī. Lai būtu iespējams mainīt esošo situāciju, nepieciešams iegūt vairāk datu par sugas izplatību ietekmējošajiem faktoriem, kā arī noskaidrot iespējamās smiltāja neļķu augšanas vietas, ar mērķi precizēt sugas populācijas lielumu. Mūsdienās nereti sugu iespējamā izplatība pētāmajā teritorijā tiek modelēta, balstoties uz attālās izpētes datiem. Lai noskaidrotu smiltāja neļķes izplatību ietekmējošos faktorus, Užavas dabas lieguma pelēkajās kāpās izveidoti 233 apļveida parauglaukumi (D= 3 m) vietās ar un …

Notices (sur des caricatures de Daumier, Grandville, Nix, Kupka et D'Ostoya)

2009

Detecting biophysical and geometrical characteristics of the canopy of three olive cultivars in hedgerow planting systems using an UAV and VIS-NIR ca…

2021

The success of olive (Olea europaea) orchards depends on the interaction between genotype, planting system and orchard management. Research efforts often collide with the lack of high-throughput monitoring technologies for effective and rapid evaluation of expressed phenotypes under field conditions. Rapid phenotyping technologies allow to acquire a large amount of information in a relatively short period, optimizing efforts and labor. In an experiment carried out in Sicily, an unmanned aerial vehicle (UAV) equipped with VIS-NIR cameras was used to monitor canopy characteristics of three olive cultivars (‘Koroneiki’, ‘Biancolilla’ and ‘Calatina’), planted at three different planting distanc…

Relation between reflectance of rice crop and indices of pollution by heavy metals in soils of albufera natural park (Valencia, Spain)

1993

13 páginas, 3 figuras, 4 tablas, 1 foto.

Multiscale study of rainfall and vegetation cover in Cameroon : spatial analysis, temporal trends, climatic and anthropogenic factors of NDVI variabi…

2011

Due to its shape and location (2°N-13°N – 8°E-16°E; proximity of the Atlantic Ocean), Cameroon is characterized by a panel of cross-regional climate encountered widely in tropical Africa. Over the region, the decrease rainfall during the second half of the last century has been shown to be associated with stronger recurrence of drier periods, specifically in the core of the rainy season. These conditions have favored the degradation of vegetation cover, driven by socioeconomic and demographic constraints. The substantial impacts on human activities and local society highlight the need to better understand how climate and environmental dynamics do interact locally. The aim of this study is t…

Time Series Analysis of Climatic Vegetation Data in the Oreto Watershed in Sicily

2008

Time series analysis of climate and vegetation variables in the Oreto watershed (Sicily, Italy)

2008

A low-cost multispectral imaging system for the characterisation of soil and small vegetation properties using visible and near-infrared reflectance

2022

Current Proximal Sensing technologies are based on multispectral imaging systems able to capture images in a few spectral bands, usually centred in VIS and NIR regions, to derive vegetation indices. However, most of such systems lack an internal radiometric calibration to estimate the actual reflectance of the observed target, making them sensitive to the local radiative environment and requiring a per-session calibration against a reference target. To overcome such dependence, the instrument described adopts an active illumination of the target surface, allowing the monitoring of soil and low vegetation surfaces by a radiometrically pre-calibrated imaging camera. The system, driven by a mi…

Metodo per il monitoraggio di superfici vegetali

2019

Si descrive un metodo da impiegare per la caratterizzazione delle coperture vegetali. A method to be used for the monitoring of vegetation surfaces is described, which includes the use of a device for measuring the spectral reflectance of vegetation using images acquired with a lightening system based on visible and infrared monoband LEDs and including devignetting, image cropping, radiometric calibration procedures and calculation of reflectance values and vegetation indices.