Search results for "Atmosphere"
showing 10 items of 673 documents
Correcting the effect of stellar spots on ARIEL transmission spectra
2020
The goal of this study is to assess the impact of the stellar spots on the extraction of the planetary transmission spectra observed by ARIEL. We develop a method to model the stellar spectrum of a star in the presence of spots by using the out-of-transit observations. It is based on a chi squared minimization procedure of the out-of-transit spectrum on a grid of stellar spectra with different sizes and temperatures of the spots. The approach allows us also to study the temporal evolution of the spots when comparing stellar spectra observed at different epochs. We also present a method to correct the transit depth variations due to non-occulted stellar spots and estimate the error we introd…
Using the transit of Venus to probe the upper planetary atmosphere
2015
The atmosphere of a transiting planet shields the stellar radiation providing us with a powerful method to estimate its size and density. In particular, because of their high ionization energy, atoms with high atomic number (Z) absorb short-wavelength radiation in the upper atmosphere, undetectable with observations in visible light. One implication is that the planet should appear larger during a primary transit observed in high energy bands than in the optical band. The last Venus transit in 2012 offered a unique opportunity to study this effect. The transit has been monitored by solar space observations from Hinode and Solar Dynamics Observatory (SDO). We measure the radius of Venus duri…
‘Can I tell?’ : Children’s participation and positioning in a secretive atmosphere in family therapy
2020
As a multifaceted phenomenon, family secrets affect interaction in the therapeutic system. This qualitative study, applying the multi‐actor Dialogical Methods for Investigations of Happening of Change, explored how children participated and positioned themselves in family therapy in a climate of family secrets. The results showed that the children were active co‐participants in the complex dynamics of a secretive atmosphere, involving themselves in the paradoxical processes of reconstructing and deconstructing the secretive and unsafe climate. In family therapy, a child’s symptomatic behaviour can function as a visible ‘cover story’ for invisible constructions of secrets, preventing sensiti…
Synthetic scene simulator for hyperspectral spaceborne passive optical sensors. Application to ESA's FLEX/sentinel-3 tandem mission
2014
The simulation of synthetic images serve scientists and engineers to study the instrument configuration as well as to develop image processing and retrieval strategies for a sensor in development. Despite synthetic scene simulators have been developed in the past in the frame of satellite missions, their functionality and flexibility to create a user-defined scene is limited by their architecture, design and implementation. This paper introduces the design of a generic scene simulator with the flexibility to generate realistic synthetic scenes by configuration of the surface and atmosphere. Following this generic design, a scene simulator is being developed for the ESA's Earth Explorer 8th …
Replacing radiative transfer models by surrogate approximations through machine learning
2015
Physically-based radiative transfer models (RTMs) help in understanding the processes occurring on the Earth's surface and their interactions with vegetation and atmosphere. However, advanced RTMs can take a long computational time, which makes them unfeasible in many real applications. To overcome this problem, it has been proposed to substitute RTMs through so-called emulators. Emulators are statistical models that approximate the functioning of RTMs. They are advantageous in real practice because of the computational efficiency and excellent accuracy and flexibility for extrapolation. We here present an ‘Emulator toolbox’ that enables analyzing three multi-output machine learning regress…
Sustainability in Polish Road Transport Sector
2013
Abstract Today, road transport is the fastest-growing segment of the freight transport in Poland. Due to its dynamic development in the 90's and low barriers to entry of new transport companies the importance of this segment still growing. Low transport rates, the ability to reach every place, as well as high flexibility and reliability of supplies carried are the main advantages of this kind of transport. However, besides the advantages, road transport has disadvantages as well, and the biggest drawback of this type of transport is its negative impact on the environment through the emission of pollutants into the atmosphere. In addition, road transport is characterized by high land consump…
On the influence of the physico-chemical properties of aerosols on the life cycle of radiation fogs
1991
A one-dimensional model of radiation fog with detailed microphysics is presented. Aerosols and cloud droplets are treated in a joint two-dimensional size distribution. Radiative fluxes are calculated as functions of the radiative properties of the time-dependent particle spectra. The droplet growth equation is solved by considering radiative effects. Turbulence is treated by means of a higher order closure model. The interaction between the atmosphere and the earth's surface is explicitly simulated. Three numerical sensitivity studies are performed to investigate the impact of the different physico-chemical properties of urban, rural and maritime aerosols on fog formation. Numerical results…
Contro il dominio dell’Arte. L’estetica quotidiana dei Futuristi
2020
Uno degli aspetti più significativi del Futurismo è la violenta ribellione contro l’arte aulica del passato. Tale polemica si traduce nella proclamazione di una nuova estetica incentrata sul corpo in movimento e sulle sue relazioni polisensoriali con l’ambiente circostante. Per mettere a fuoco questa prospettiva estetica si prenderanno in considerazione le cosiddette “ambientazioni futuriste”. Esse segnano il momento cruciale in cui la creatività futurista si allarga dall’arte allo spazio quotidiano sia pubblico sia privato, sia domestico sia urbano. Inoltre le ambientazioni attestano il ruolo pionieristico che i futuristi hanno avuto nell’ avviare una riflessione sullo spazio vissuto che m…
Estimation of the geogenic carbon degassing of Greece
2019
Abstract Greece belongs to the most geodynamically active regions of the world and as such it has to be considered an area of intense geogenic degassing. Here we review all the papers already published in the scientific literature on both the geochemistry of gas manifestations and the CO2 and CH4 release, in an attempt to obtain the first nationwide inventory of the natural output of these carbon gases in Greece. The best studied and most exhaling area is the South Aegean Active Volcanic Arc (SAAVA), which releases more than 1.3 × 105 tons of CO2 per year. Continental Greece, on the contrary, is much less studied but may release CO2 in the same order of magnitude in its eastern-central and …
Magnetic Properties Experiments on the Mars Exploration Rover Spirit at Gusev Crater
2004
The magnetic properties experiments are designed to help identify the magnetic minerals in the dust and rocks on Mars—and to determine whether liquid water was involved in the formation and alteration of these magnetic minerals. Almost all of the dust particles suspended in the martian atmosphere must contain ferrimagnetic minerals (such as maghemite or magnetite) in an amount of ∼2% by weight. The most magnetic fraction of the dust appears darker than the average dust. Magnetite was detected in the first two rocks ground by Spirit.