Search results for "Law"

2018

The Radar Vegetation Index (RVI) is a well-established microwave metric of vegetation cover. The index utilizes measured linear scattering intensities from co- and cross-polarization and is normalized to ideally range from 0 to 1, increasing with vegetation cover. At long wavelengths (L-band) microwave scattering does not only contain information coming from vegetation scattering, but also from soil scattering (moisture & roughness) and therefore the standard formulation of RVI needs to be revised. Using global level SMAP L-band radar data, we illustrate that RVI runs up to 1.2, due to the pre-factor in the standard formulation not being adjusted to the scattering mechanisms at these lo…

The Synergistic Impacts of Anthropogenic Stressors and COVID-19 on Aquaculture: A Current Global Perspective

2021

13 pages, 6 figures, 2 tables.-- This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License

Flares from small to large: X-ray spectroscopy of Proxima Centauri with XMM-Newton

2003

(Abridged) We report results from a comprehensive study of the nearby M dwarf Proxima Centauri with the XMM-Newton satellite. We find strongly variable coronal X-ray emission, with flares ranging over a factor of 100 in peak flux. The low-level emission is found to be continuously variable. Several weak flares are characteristically preceded by an optical burst, compatible with predictions from standard solar flare models. We propose that the U band bursts are proxies for the elusive stellar non-thermal hard X-ray bursts suggested from solar observations. A very large X-ray flare was observed in its entirety, with a peak luminosity of 3.9E28 erg/s [0.15-10 keV] and a total X-ray energy of 1…

Complex geometry and kinematics of subsidiary faults within a carbonate-hosted relay ramp

2019

Abstract Minor fault geometry and kinematics within relay ramps is strongly related to the stress field perturbations that can be produced when two major fault segments overlap and interact. Here we integrate classical fieldwork and interpretation of a virtual outcrop to investigate the geometry and kinematics of subsidiary faults within a relay ramp along the Tre Monti normal fault in the Central Apennines. Although the Tre Monti fault strikes parallel to the regional extension (NE-SW) it shows predominant dip-slip kinematics, suggesting a NW-SE oriented extension acting at sub-regional scale (1–10 km). Conversely, the slickenlines collected on the front segment of the relay ramp highlight…

Approach to a water safety plan for recreational waters: disinfection of a drainage pumping station as an unconventional point source of fecal contam…

2020

Abstract In the context of the management of bathing water quality, the intermittent contamination of rainwater drainage pumps (unconventional point sources) could be controlled by peracetic acid disinfection. Thus, a field experimental study was carried out to set up a water safety plan, determining the monitoring parameters and the critical limit for corrective actions. With a 0.5 mg/l dosage, the average logarithmic microbial reduction was 0.50 ± 0.48 for Escherichia coli (EC) and 0.43 ± 0.54 for intestinal enterococci. Among the chemical and physical parameters that could be monitored in real time, the oxidation–reduction potential was the only one able to predict the microbial concentr…

Climate change policies and agendas: facing implementation challenges and guiding responses

2020

Climate policies are essential to mitigate climate change and to develop successful adaptation processes. However, there is a paucity of international studies that analyse the status of climate change policies. This paper reports on research undertaken in a sample of 13 highly diverse countries, in regards to their geography, socioeconomic development, vulnerability elements, adaptation, and climate-risks. The results draw attention to the global spread and standardisation of climate change policies, namely through the adoption of comprehensive National Adaptation Plans/Strategies (NAPs/NASs) that include mitigation measures and evaluation mechanisms. Although NAPs tend to take into account…

Scale: The Universal Laws of Growth, Innovation, Sustainability, and the Pace of Life in Organisms, Cities, Economies, and Companies

2020

National audience

PHYSICS-based retrieval of scattering albedo and vegetation optical depth using multi-sensor data integration

2017

Vegetation optical depth and scattering albedo are crucial parameters within the widely used τ-ω model for passive microwave remote sensing of vegetation and soil. A multi-sensor data integration approach using ICESat lidar vegetation heights and SMAP radar as well as radiometer data enables a direct retrieval of the two parameters on a physics-derived basis. The crucial step within the retrieval methodology is the calculus of the vegetation scattering coefficient KS, where one exact and three approximated solutions are provided. It is shown that, when using the assumption of a randomly oriented volume, the backscatter measurements of the radar provide a sufficient first order estimate and …

X-ray flare oscillations track plasma sloshing along star-disk magnetic tubes in Orion star-forming region

2018

Pulsing X-ray emission tracks the plasma echo traveling in an extremely long magnetic tube that flares in an Orion Pre-Main Sequence (PMS) star. On the Sun, flares last from minutes to a few hours and the longest-lasting typically involve arcades of closed magnetic tubes. Long-lasting X-ray flares are observed in PMS stars. Large-amplitude (~20%) long-period (~3 hours) pulsations are detected in the light curve of day-long flares observed by the Advanced CCD Imaging Spectrometer (ACIS) on-board Chandra from PMS stars in the Orion cluster. Detailed hydrodynamic modeling of two flares observed on V772 Ori and OW Ori shows that these pulsations may track the sloshing of plasma along a single l…

Understanding the Origins of Problem Geomagnetic Storms Associated with "Stealth" Coronal Mass Ejections.

2021

Geomagnetic storms are an important aspect of space weather and can result in significant impacts on space- and ground-based assets. The majority of strong storms are associated with the passage of interplanetary coronal mass ejections (ICMEs) in the near-Earth environment. In many cases, these ICMEs can be traced back unambiguously to a specific coronal mass ejection (CME) and solar activity on the frontside of the Sun. Hence, predicting the arrival of ICMEs at Earth from routine observations of CMEs and solar activity currently makes a major contribution to the forecasting of geomagnetic storms. However, it is clear that some ICMEs, which may also cause enhanced geomagnetic activity, cann…