Search results for "VEGETATION"
showing 10 items of 1069 documents
Mapping productivity and essential biophysical parameters of cultivated tropical grasslands from sentinel-2 imagery.
2020
Nitrogen (N) is the main nutrient element that maintains productivity in forages
Synergy of Sentinel-1 and Sentinel-2 Time Series for Cloud-Free Vegetation Water Content Mapping with Multi-Output Gaussian Processes
2023
Optical Earth Observation is often limited by weather conditions such as cloudiness. Radar sensors have the potential to overcome these limitations, however, due to the complex radar-surface interaction, the retrieving of crop biophysical variables using this technology remains an open challenge. Aiming to simultaneously benefit from the optical domain background and the all-weather imagery provided by radar systems, we propose a data fusion approach focused on the cross-correlation between radar and optical data streams. To do so, we analyzed several multiple-output Gaussian processes (MOGP) models and their ability to fuse efficiently Sentinel-1 (S1) Radar Vegetation Index (RVI) and Senti…
Determinants of the interannual relationships between remote sensed photosynthetic activity and rainfall in tropical Africa
2007
International audience; The response of photosynthetic activity to interannual rainfall variations in Africa South of the Sahara is examined using 20 years (1981-2000) of Normalised Difference Vegetation Index (NDVI) AVHRR data. Linear correlations and regressions were computed between annual NDVI and annual rainfall at a 0.5° latitude/longitude resolution, based on two gridded precipitation datasets (Climate Prediction Center Merged Analysis of Precipitation [CMAP] and Climatic Research Unit [CRU]). The spatial patterns were then examined to detect how they relate to the mean annual rainfall amounts, land-cover types as from the Global Land Cover 2000 data set, soil properties and soil typ…
TISSBERT: A benchmark for the validation and comparison of NDVI time series reconstruction methods
2018
[EN] This paper introduces the Time Series Simulation for Benchmarking of Reconstruction Techniques (TISSBERT) dataset, intended to provide a benchmark for the validation and comparison of time series reconstruction methods. Such methods are routinely used to estimate vegetation characteristics from optical remotely sensed data, where the presence of clouds decreases the usefulness of the data. As for their validation, these methods have been compared with previously published ones, although with different approaches, which sometimes lead to contradictory results. We designed the TISSBERT dataset to be generic so that it could simulate realistic reference and cloud-contaminated time series …
Longhorn beetles of the Ficuzza woods (W Sicily, Italy) and their relationship with plant diversity (Coleoptera, Cerambycidae
2010
The woods in Sicily are the result of centuries of anthropogenic activities that have reduced the surface of wood and changed the original composition even with the introduction of alien species to native flora. The value in terms of biodiversity of these forests remains, however, high for they are the last refuge areas for many animals and plant species. This study was conducted within the Ficuzza woods (West Sicily), extended about 5,000 hectares on the slopes of limestone-dolomite rock of Busambra (1615 m asl), within which lies the largest remaining forest area in western Sicily. It is an area with a wide diversity of vegetation, represented mainly by native forests (holm oak, cork oak,…
On the processing of field spectroradiometric data for remote sensing mapping of submerged vegetation in coastal zones and lagoon environments
2008
Monitoraggio e valutazione del danno degli insetti defogliatori su diverse specie di Quercus in Sicilia
Most of the insects feeding on oaks are usually ‘in balance’ with their host trees, causing occasional damage. When severe defoliations regularly occur, oak trees vulnerability to the complex of factors causing the overall decline syndrome can increase. Assessing canopy damage due to defoliating insects through the usually adopted visual methods is quite difficult, requiring highly experienced operators and a long time spent to collect field data. The present research has been carried out to investigate the different susceptibility of Sicilian oak species to defoliating insect attacks, in particular the oak moth Tortrix viridana (L.) (Lepidoptera Tortricidae), with the aim to assess the rel…
Investigation of a Gravel-Bed River’s Pattern Changes: Insights from Satellite Images
2021
Changes in river pattern have been documented in the literature. The recognition of islands and vegetated patches, which is indicative of the evolution processes, requires simultaneous information at different points and at different times and field studies are still difficult and scarce. The present work, focusing the attention on a gravel-bed river, explores the possibility to conduct a first-step pattern changes analysis by identifying the evolution of the morphological features and taking information of islands and vegetated patches from satellite images easily available from Google Earth. The study is conducted by combining the information taken from both the satellite images and the f…
Zbiorowiska roślinne doliny Czerwonej Wody w Parku Narodowym Gór Stołowych
2018
The Czerwona Woda River is the main watercourse in the Stołowe Mountains National Park and drains the major part of the Stołowe Mts. It was regulated in the past, but its channel has been spontaneously naturalized. Now, managed spruce forests grow along almost the entire length of this small mountain stream. The aims of the present study were to investigate diversity of plant communities connected with the Czerwona Woda stream and to prepare detailed vegetation maps. The results obtained can potentially be a reference for future restoration projects implemented in the Stołowe Mountains National Park. As a result of vegetation mapping, there were distinguished 20 plant communities representa…
Experimental investigation of flow turbulent structure in a high-amplitude vegetated meandering laboratory flume
2018
The present work focuses on high-curved channels which are characterized by a complex flow turbulent structure. The specific aim of work is to analyze the evolution of turbulent coherent motion in the pres-ence of vegetation on the bed.