Search results for "Planet"
showing 10 items of 5662 documents
Limit Periodic Sets
1998
As explained at the end of the previous chapter, the most difficult problem in the study of bifurcations in a family of vector fields on a surface of genus 0 is the control of the periodic orbits. In fact, in generic smooth families the periodic orbits will be isolated for each value of the parameter. For analytic families we have two possibilities for each orbit: it may be isolated or belong to a whole annulus of periodic orbits. In this last case and for the parameter values for which the system has infinitely many periodic orbits, the vector field has a local analytic first integral and the nearby vector fields in the family may be studied by the perturbation theory introduced in Chapter…
Multi-channel and multi-angle algorithms for estimating sea and land surface temperature with ATSR data
1996
Abstract A study has been carried out using LOWTRAN-7 simulations of the Along-Track Scanning Radiometer (ATSR) data at 11 and 12 μm wavelengths to compare the merits of the multi-angle technique with those of the currently used multi-channel technique (split-window method) to retrieve both sea surface temperature (SST) and land surface temperature (LST). To this end a simple single-channel double-angle viewing model is presented, which relates actual surface temperature to the two brightness temperatures measured from space in the two views of interest (ATSR nadir and forward). Subsequently, statistical retrieval coefficients for the double angle and split-window techniques are derived via…
Land surface emissivity retrieval from satellite data
2012
As an intrinsic property of natural materials, land surface emissivity LSE is an important surface parameter and can be derived from the emitted radiance measured from space. Besides radiometric calibration and cloud detection, two main problems need to be resolved to obtain LSE values from space measurements. These problems are often referred to as land surface temperature LST and emissivity separation from radiance at ground level and as atmospheric corrections in the literature. To date, many LSE retrieval methods have been proposed with the same goal but different application conditions, advantages, and limitations. The aim of this article is to review these LSE retrieval methods and to…
Impact of Land Cover Change Induced by a Fire Event on the Surface Energy Fluxes Derived from Remote Sensing
2015
Forest fires affect the natural cycle of the vegetation, and the structure and functioning of ecosystems. As a consequence of defoliation and vegetation mortality, surface energy flux patterns can suffer variations. Remote sensing techniques together with surface energy balance modeling offer the opportunity to explore these changes. In this paper we focus on a Mediterranean forest ecosystem. A fire event occurred in 2001 in Almodovar del Pinar (Spain) affecting a pine and shrub area. A two-source energy balance approach was applied to a set of Landsat 5-TM and Landsat 7-EMT+ images to estimate the surface fluxes in the area. Three post-fire periods were analyzed, six, seven, nine, and 11 y…
The REFLEX galaxy cluster survey VIII. Spectroscopic observations and optical atlas
2009
We present the final data from the spectroscopic survey of the ROSAT-ESO Flux-Limited X-ray (REFLEX) catalog of galaxy clusters. The REFLEX survey covers 4.24 steradians (34% of the entire sky) below a declination of 2.5 deg and at high Galactic latitude (|b| > 20 deg). The REFLEX catalog includes 447 entries with a median redshift of 0.08 and is better than 90% complete to a limiting flux fx = 3x10^{-12} erg s^{-1} cm^{-2} (0.1 to 2.4 keV), representing the largest statistically homogeneous sample of clusters drawn from the ROSAT All-Sky Survey (RASS) to date. Here we describe the details of the spectroscopic observations carried out at the ESO 1.5 m, 2.2 m, and 3.6 m telescopes, as wel…
Rare earth elements distribution in seawater and suspended particulate of the Central Mediterranean Sea
2004
Rare earth element (REE) content in suspended and dissolved phases from the Strait of Sicily (Central Mediterranean Sea) has been measured. Vertical profiles of several dissolved REEs along the water column reflect the 3-D oceanographic features of the studied area and identifies the different water masses present there. Shale-normalized REE distribution patterns and derived parameters calculated for the suspended particulate show different atmospheric dust-surface inputs and their interactions with seawater. Finally, combined information from [La/Yb]N, ratios, REE/La ratios and Eu anomalies measured in the suspended particulate suggest an important contribution of volcanic materials from t…
Sustainable Development and the Practice of Spatial Planning: A Proposal of Criteria for Measuring the Overall Sustainability of Planning Actions in …
2021
The sustainable city debate is gaining ground in recent years, featuring as a prominent issue in several policy documents of the European Commission, and enjoying support by the main organisations and institutions at international level. At the same time, improving local governance standards by involving citizens in local decision-making is a recurring issue in the debate on local democracy and enhancement of community cohesion. This paper presents an analysis of the European experience and best practice relating sustainable development to the day-to-day practice of spatial planning. The overall purpose is creating a proposal of indicators for measuring the sustainability of planning action…
Impacts of the COVID-19 Pandemic on Social Development and its Implications for the Transition to Sustainable Development
2021
Abstract The COVID-19 crisis has revealed the vulnerability of people, societies and economies and has forced a rethinking of the economic and social activities of an organization. The crisis requires strong responses based on solidarity, cooperation and responsibility. Socio-economic organizations (associations, cooperatives, alliances, and social enterprises) whose business models are based on these principles can help reshape economies and societies after the crisis.
La comprensión e impulso de la Sostenibilidad: un requisito imprescindible para una acción educativa y ciudadana eficaz
2019
Diagnósticos concordantes de la actual situación de emergencia planetaria muestran la necesidad de una urgente transición a sociedades que hagan posible una vida justa y digna al conjunto de seres humanos y a las futuras generaciones, al tiempo que se protege la biodiversidad y se revierte la degradación del medioambiente. Esta problemática ha dado lugar a propuestas con distintas denominaciones -transición a la sostenibilidad, decrecimiento, crecimiento inclusivo… - generando controversias que pueden dificultar el establecimiento de una agenda común para hacer frente a los problemas. Proponemos por ello centrar el debate en analizar las medidas que se consideran necesarias, en particular p…
Towards Municipal Environmental Development: Environmental Management Systems for Local Formal Education Establishments
2021
Educational institutions create certain environmental impacts in their operation – these impacts can be grouped into the sectors of waste, water, energy, transport and others. There is a need for educational institutions to adopt effective environmental management systems in order to reduce these impacts, as well as those of the whole municipality. The Eco-Schools programme is one of the most comprehensive and popular models of environmental education and management in the world. In recent years, the Eco-Schools programme has proved its effectiveness in numerous evaluations in several countries. The programme aims to raise awareness about environmental issues. Therefore, this programme enco…