Search results for "Meteor"
showing 10 items of 4734 documents
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 …
Estudio de la radiación neta en zonas semiáridas utilizando modelos lineales y neuronales y la sinergia entre GERB y SEVIRI
2012
Las regiones áridas o semiáridas se caracterizan por una distribución irregular de los recursos hídricos, lo que muchas veces constituye una limitación para el desarrollo de una determinada región. La variabilidad hidrológica de estas regiones se debe a la mala distribución espacial y temporal de la lluvia, a la topografía heterogénea y a los cambios de origen antropogénicos que muchas veces conducen a procesos de degradación y de desertificación. Como en estas regiones la evapotranspiración explica una parte significativa de la pérdida de agua hacia la atmósfera, el estudio y modelización de la radiación neta en superficie (Rn), es de suma importancia, una vez que las estimaciones o medici…
Environmental hazard and water quality: the River Platani basin
2007
The River Platani, situated in the western side of Sicily, is one of the greatest rivers of the island. It runs for about 103 Km and the basin extends to about 1,784.9 Km. It rises near Santo Stefano Quisquina (Ag); the river flows to Capo Bianco (Ag) ends in the Mediterranean Sea. The morphology of the basin is predominantly characterized by rises of modest entities with slopes sweet or calanques. In the containing gypsum and carbonatic stony heaps are diffused the karst phenomena. In the Platani basin some mines are located of rock salt and potassium salts; today the mines are closed after a long activity and they interact with the geomorphology of the territory and on the water quality o…
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…
The Role of Excited Oxygen Molecules in the Formation of the Secondary Ozone Layer at 87 to 97 km
2018
The secondary ozone layer is located at elevations of 87 to 97 km in the upper mesosphere – lower thermosphere. It overlaps with the ionospheric D-layer. Daytime intensive UV radiation is dissociating O2 molecules to O atoms and photoexcitating O2 molecules up to 11.07eV level. Ozone photolysis between the wavelengths of 118.7–121.6 nm produces three oxygen atoms from one ozone molecule. Collision reactions of O2(B3 Σu —) and O2(X3 Σg —, υ≥26) with O2(X3 Σg —, υ=0) produce additional oxygen atoms. The number of oxygen atoms is maintained at such a high level that a small but significant ozone concentration survives. UV radiation weakens radically during the night. The number of O atoms show…
THE EVOLUTION OF THE SEWAGE TREATMENT PROCESS IN ROMANIA IN THE LAST 30 YEARS: CASE STUDY RÂMNICU VÂLCEA
2012
The evolution of the sewage treatment process in Romania in the last 30 years: case study Râmnicu Vâlcea. Most studies made at national level in the domain of hydrology target the surface water topic, analyzing the hydrometric and hydrologic characteristics and the quality of the water for certain catchment areas. This paper aims instead the relatively new field of urban hydrology, more exactly the urban wastewater treatment process. The study is based on the observations made in the first half of the year 2010 at the wastewater treatment plant from Râmnicu Vâlcea and on the analysis of some relevant wastewater quality indicators before and after the treatment process for the period between…
Stress sensitivity of stylolite morphology
2009
International audience; Stylolites are rough surfaces that form by localized stress-induced dissolution. Using a set of limestone rock samples collected at different depths from a vertical section in Cirque de Navacelles (France), we study the influence of the lithostatic stress on the stylolites morphology on the basis of a recent morphogenesis model. We measured the roughness of a series of bedding-parallel stylolites and show that their morphology exhibits a scaling invariance with two self-affine scaling regimes separated by a crossover-length (L) at the millimeter scale consistent with previous studies. The importance of the present contribution is to estimate the stylolite formation s…
Emulation of Sun-Induced Fluorescence from Radiance Data Recorded by the HyPlant Airborne Imaging Spectrometer
2021
The retrieval of sun-induced fluorescence (SIF) from hyperspectral radiance data grew to maturity with research activities around the FLuorescence EXplorer satellite mission FLEX, yet full-spectrum estimation methods such as the spectral fitting method (SFM) are computationally expensive. To bypass this computational load, this work aims to approximate the SFM-based SIF retrieval by means of statistical learning, i.e., emulation. While emulators emerged as fast surrogate models of simulators, the accuracy-speedup trade-offs are still to be analyzed when the emulation concept is applied to experimental data. We evaluated the possibility of approximating the SFM-like SIF output directly based…
The Mechanical Impact of Water Affected the Soil Physical Quality of a Loam Soil under Minimum Tillage and No-Tillage: An Assessment Using Beerkan Mu…
2021
The multi-height (low, L = 3 cm
On-Orbit Degradation of Solar Instruments
2013
International audience; We present the lessons learned about the degradation observed in several space solar missions, based on contributions at the Workshop about On-Orbit Degradation of Solar and Space Weather Instruments that took place at the Solar Terrestrial Centre of Excellence (Royal Observatory of Belgium) in Brussels on 3 May 2012. The aim of this workshop was to open discussions related to the degradation observed in Sun-observing instruments exposed to the effects of the space environment. This article summarizes the various lessons learned and offers recommendations to reduce or correct expected degradation with the goal of increasing the useful lifespan of future and ongoing s…