Search results for "Planetary Science"
showing 10 items of 4367 documents
Der Wärme- und Wasserdampfhaushalt der freien Atmosphäre
1951
Die Zahlenwerte des horizontalen Warmetransportes durch Grosaustausch, die man bisher kennt, sind schwierig zu deuten; insbesondere gilt dies fur die Umkehr des meridionalen Stromes in der mittleren Troposphare. Es wird deshalb ein Verfahren angegeben, aus den Radiosondenaufstiegen eines Stationsdreiecks die Warmebilanz in der freien Atmosphare zu bestimmen. Fur das Jahr von April 1949 bis Marz 1950 wird in einem England, die Nordsee und Nordwestdeutschland uberdeckenden Gebiet eine Abkuhlung der Troposphare von 0,5°/Tag am Boden, zunehmend auf 1,8°/Tag bei 300 mb gefunden; die Stratosphare zeigt eine leichte Erwarmung. Uber dem Ozeangebiet westlich Englands besteht am Boden Erwarmung von 0…
Numerical analysis of ionosphere disturbances and Schumann mode splitting in the Earth-ionosphere cavity
2008
[1] The variability of ionosphere properties plays an important role in the Schumann resonances (SR), amplitudes, frequencies, and Q factor. Therefore, as atmosphere ionization is related to solar activity, SR could be devised as a source of indirect parameters that locally from the surface of the Earth could provide space weather information. A proper understanding of this link to SR parameters can be obtained through finite difference time domain (FDTD) simulations, specifically with the numerically obtained modes and frequencies that relate frequency shifts to the day-night asymmetry and polar inhomogeneities. Day-Night asymmetry is observed to have a minor influence in SR; however, larg…
Personality, social support and affective states during simulated microgravity in healthy women
2009
This study investigated the time-course of stress and recovery states and their relations to social support and personality traits in healthy women during a long-term head-down tilt bed rest. Personality, social support and affective states were assessed in 16 women exposed to simulated microgravity for a 60-day duration involving three stages: a 20-day baseline control period (BDC), a 60-day head-down tilt bed rest (HDT) and a 20-day post-HDT ambulatory recovery period (R+). Participants were divided into two groups: an exercise (Exe, n = 8) and a control group (Ctl, n = 8). All the participants experienced significantly more stress during the HDT period. But exercise did not improve the i…
Validation of Landsat-7/ETM+ Thermal-Band Calibration and Atmospheric Correction With Ground-Based Measurements
2010
Ground-based measurements of land-surface temperature (LST) performed in a homogeneous site of rice crops close to Valencia, Spain, were used for the validation of the calibration and the atmospheric correction of the Landsat-7 Enhanced Thematic Mapper Plus (ETM+) thermal band. Atmospheric radiosondes were launched at the test site around the satellite overpasses. Field-emissivity measurements of the near-full-vegetated rice crops were also performed. Seven concurrences of Landsat-7 and ground data were obtained in July and August 2004-2007. The ground measurements were used with the MODTRAN-4 radiative transfer model to simulate at-sensor radiances and brightness temperatures, which were c…
A Precise Photometric Ratio via Laser Excitation of the Sodium Layer II: Two-photon Excitation Using Lasers Detuned from 589.16 nm and 819.71 nm Reso…
2020
This article is the second in a pair of articles on the topic of the generation of a two-color artificial star (which we term a "laser photometric ratio star," or LPRS) of de-excitation light from neutral sodium atoms in the mesosphere, for use in precision telescopic measurements in astronomy and atmospheric physics, and more specifically for the calibration of measurements of dark energy using type Ia supernovae. The two techniques respectively described in both this and the previous article would each generate an LPRS with a precisely 1:1 ratio of yellow (589/590 nm) photons to near-infrared (819/820 nm) photons produced in the mesosphere. Both techniques would provide novel mechanisms f…
Analysis of broadband surface BRDFs derived from TOA SW CERES measurements for surfaces classified by the IGBP land cover
2012
Most studies on the reflectance properties of the Earth's surface are addressed estimating the bidirectional reflectance distribution function (BRDF) of high spatial resolution and high spectral resolution satellite measurements. This article assesses the development of broadband (BB) BRDFs from radiances corresponding to large footprints classified according to the International Geosphere-Biosphere Programme (IGBP) land-cover classification. Top-of-atmosphere (TOA) shortwave (SW) CERES (Clouds and the Earth's Radiant Energy System) measurements are employed to invert the bidirectional reflectance factor (BRF) Rahman–Pinty–Verstraete (RPV) model for regions identified with the same IGBP typ…
Revision of the Single-Channel Algorithm for Land Surface Temperature Retrieval From Landsat Thermal-Infrared Data
2009
This paper presents a revision, an update, and an extension of the generalized single-channel (SC) algorithm developed by Jimenez-Munoz and Sobrino (2003), which was particularized to the thermal-infrared (TIR) channel (band 6) located in the Landsat-5 Thematic Mapper (TM) sensor. The SC algorithm relies on the concept of atmospheric functions (AFs) which are dependent on atmospheric transmissivity and upwelling and downwelling atmospheric radiances. These AFs are fitted versus the atmospheric water vapor content for operational purposes. In this paper, we present updated fits using MODTRAN 4 radiative transfer code, and we also extend the application of the SC algorithm to the TIR channel …
Temperature and Emissivity Separation From MSG/SEVIRI Data
2014
In this paper, we analyze the feasibility of applying the temperature and emissivity separation (TES) algorithm to thermal-infrared data acquired with three bands of the Spinning Enhanced Visible and Infrared Imager (SEVIRI) onboard the Meteosat Second Generation platform (SEVTES). The performance of the SEVTES algorithm was tested using data simulated over different atmospheric conditions and surface emissivities, with errors around 1.5% for emissivity and 1.5 K for temperature when atmospheric correction is accurate enough. In contrast, errors on land-leaving radiances higher than 2% or uncertainties on total atmospheric water vapor amount higher than 5% lead to errors on emissivity highe…
Dal game-based learning ai serious games: alcune prospettive per l’apprendimento mediato dalla tecnologia digitale
2023
In the last years, serious games have become popular in media education as they are useful tools in engaging, motivating, and helping students learn. However, few studies investigate the long-term effects of game-based learning, and many scholars declare themself skeptical about the learning mediated by digital technology. This paper reflects on the importance of new media and serious games for young people belonging to the Net Generation as defined by Prensky. In particular, I support the idea that game-based learning reflects a broader change in our society, coinciding with the rise of the phenomenon of Gamification and the Homo Ludens paradigm. Apart from the limitations of technology-me…
Database Versioning 2.0, a Transparent SQL Approach Used in Quantitative Management and Decision Making
2015
Abstract Managerial decisions are based on accurate information and in today's time raw data is produced even with a stroke of a key. Regardless of the data creating process one needs to know how the information was extracted and which pool of data was used. One important factor is time therefore we need to structure it in layers of data history in such a way that it can be analyzed, (post)process, in order to be able to retrieve valuable information. The simplest way is to use a Database Management System (DBMS), but even with such a management system we face the issue of making it a self-contained database on each version of data added. Our proposed system, a continuation of previous work…