47 research outputs found
Un modelo docente para sensibilizar sobre la sostenibilidad empleando la geoinformación
The increase in geoinformation and its integrated use in cloud-based geographic information systems, or Web GIS, facilitates visualization of data and helps to improve our understanding of socio-economic factors as well as the natural landscape. Effective application of these tools in the classroom requires a change in teachers’ pedagogies. Thus, a review of existing pedagogies and a brief questionnaire given to teachers with lots of experience of using Web GIS, was carried out in order to identify how they were integrating online interactive maps into their teaching to make learning more effective. The results led to the development of a series of learning scenarios, or vignettes. These all use the visualization provided by online maps, to encourage more critical and reasoned learning. They also contribute to educating for sustainability, as they highlight trends and interrelationships that are intended to promote transformative action, beyond the theoretical knowledge and application of the Sustainable Development Goals. Direct observation in teacher training classrooms and detailed discussion over each result obtained has validated a teaching model. To support the use of these materials and the application of the model, a training course has been designed for teachers who are new to the profession or those who are interested in integrating these tools into their teaching. To date, trainee teachers who have been introduced to the model have expressed their satisfaction with this new way of working in secondary classrooms.El incremento de la geoinformación y su integración en los sistemas de información geográfica en la nube o SIG Web, facilitan la visualización de los datos y una mejora de la comprensión de la realidad socioeconómica y territorial del paisaje. La efectividad de estas herramientas en las aulas hace necesario un cambio en las pedagogías de los docentes. Así, se ha realizado un seguimiento de las pedagogías existentes y un pequeño cuestionario a profesores experimentados en el empleo de SIG Web con la finalidad de formular cómo integrar los mapas interactivos en línea en la docencia para un aprendizaje más eficiente y elaborar con estos resultados una serie de situaciones de aprendizaje o vignettes. En todas ellas se emplean mapas en línea cuya visualización fomenta el aprendizaje crítico y razonado. Con ellos también se colabora en educar para la sostenibilidad, ya que evidencian tendencias e interrelaciones que se pretende promuevan una acción transformadora, más allá del conocimiento y aplicación teórica de los Objetivos de Desarrollo Sostenible. La observación directa en las aulas de formación del profesorado y una detallada discusión sobre cada resultado que se va obteniendo han validado el modelo docente creado. Para apoyar el empleo de estos materiales y la aplicación del modelo se ha diseñado un curso de formación para el profesorado que se inicia en la profesión o aquél otro con interés en integrar estas herramientas en su docencia. Hasta el momento los profesores en formación que han conocido este modelo han mostrado su satisfacción, su satisfacción por esta nueva forma de trabajar en las aulas de secundaria
Advanced exploitation of Ground-Based measurements for Atmospheric Chemistry and Climate Applications "AGACC"
We live in an era in which human activities are causing significant changes to the atmospheric environment which result in local to global consequences on the ecosystems. Changes in the atmospheric composition impact our climate via chemical and dynamical feedback mechanisms; in many instances they also affect air quality, and the health of the biosphere. Monitoring and understanding those changes and their consequences is fundamental to establish adequate actions for adaptation to and mitigation of the environmental changes. Furthermore, after implementation of regulatory measures like the Montreal Protocol, it is necessary to verify whether the measures are effective. This can only be achieved if we have adequate detection methods and a reliable long record of a series of key geophysical parameters.
Thus the AGACC project contributes to the provision of basic new knowledge regarding the atmospheric composition and its changes, based on advanced groundbased monitoring, in combination with satellite and numerical modelling data. Its results are integrated in ongoing international research programmes.
The general objective of AGACC has been to improve and extend the groundbased detection capabilities for a number of climate-related target species and, based hereupon, analyse past and present observations to derive new information about the atmospheric composition, its variability and long-term changes. Despite the advent of a growing and more performant fleet of Earth Observation satellites, ground-based observations are still indispensable to (1) guarantee long-term continuity, homogeneity and high quality of the data, and (2) to underpin the satellite data for calibration and (long-term) validation.
A first target gas is atmospheric water vapour. It is the key trace gas controlling weather and climate. It is also the most important greenhouse gas in the Earth’s atmosphere. Its amount and vertical distribution are changing, but how and why?
Especially in the upper troposphere - lower stratosphere, the radiative effects of changes in the water vapour are significant and should be quantified. The measurement of water vapour is a hot topic since several years. It is a challenge, because water vapour exhibits a large gradient in its concentration when going from the ground to the stratosphere, and because it is highly variable in time and space. For example, we have found that the time scale of the variations of the total water vapour amount at Jungfraujoch is in the order of minutes.
In AGACC, we have therefore investigated various experimental techniques to measure the concentration of water vapour in the atmosphere, focusing on the total column as well as on the vertical distribution in the troposphere up to the lower stratosphere. The retrieval of water vapour vertical profiles and total columns from ground-based FTIR data has been initiated at three very different stations where correlative data for verification are available, namely Ukkel (± sea level, mid-latitude), Ile de La Réunion (± sea level, tropical) and Jungfraujoch (high altitude, mid-latitude), with promising results. In particular, at Jungfraujoch, it has been demonstrated that the precision of the FTIR integrated water vapour (IWV) measurements is of order 2%. The capability to retrieve individual isotopologues of water vapour, and to monitor their daily and diurnal variations, has also been demonstrated. This could open new ways to study in the future the role of water vapour in the radiative balance, the global circulation, precipitation etc. We also started joint exploitation of ground-based FTIR and satellite IASI data for water vapour and its isotopologues, in order to exploit fully the potential of the existing instrumentation.
A correction method for the radiosoundings at Ukkel has been successfully implemented, resulting in a homogeneous and reliable time series from 1990 to 2008 from which trends in upper troposphere humidity (UTH) and tropopause characteristics have been derived. One observes a rising UTH until September 2001, followed by a decline, accompanied by a descent and heating of the tropopause up to the turning point and an ascent and cooling afterwards. The changes after September 2001 in the upper troposphere can be explained by surface heating and convective uplift. At Jungfraujoch, one does not observe any significant trend in the total water vapour abundance above the station over the 1988-2010 time period, although significant positive summer and negative winter trends have been detected.
We have made a quantitative statistical comparison between ground-based FTIR, CIMEL, GPS and integrated (corrected) radio sounding measurements of the IWV at Ukkel. This work is important to better characterize the different sensors in order to exploit together different observations made by different instruments.
A second target species is atmospheric aerosol. There is a very large variety of aerosol both from natural or anthropogenic origin. One of the reasons why they are so important is that they affect the optical properties of the atmosphere. In particular, it has been demonstrated in previous studies that the aerosols have a large impact on the quantity of harmful UV-B radiation received at the Earth’s surface. The latest IPCC Report also stressed that the radiative forcing caused by atmospheric aerosols is one of the largest uncertainties in determining the total radiative forcing in the atmosphere. Better monitoring capabilities of aerosol properties can therefore improve our understanding and forecasting of the atmospheric processes and evolution, and in particular of UV-B and climate changes.
Several measurement techniques are now operational in the AGACC consortium for the ground-based monitoring of aerosol properties. These are the Brewer spectrometer and CIMEL observations at Ukkel, the latter contributing also to the AERONET network since July 2006, and the newly developed MAXDOAS observations. Unlike CIMEL and Brewer measurements, that provide the total Aerosol Optical Depth, it has been demonstrated that the MAXDOAS measurements also provide additional information about the vertical distribution of the aerosol extinction in the lowest kilometres of the troposphere. A better understanding of the ultimate capabilities of MAXDOAS aerosol remote sensing has been gained through participation to the international CINDI campaign (Cabauw Intercomparison Campaign of Nitrogen Dioxide measuring Instruments ) in summer 2009. The combination of Brewer, CIMEL and MAXDOAS instruments gives us a remote-sensing dataset that will enable a more comprehensive characterization of the tropospheric aerosol optical properties. The usefulness of these aerosol observations has already been demonstrated in the improvement of the UVindex predictions for the general public. Another application is their use as input data in the retrieval of vertical profiles of tropospheric pollutants from MAXDOAS measurements, like tropospheric NO2 and formaldehyde.
Third we have focused on a few climate-related trace gases. Changing greenhouse gas and aerosol concentrations directly affect the radiative budget of the atmosphere, and therefore climate. But many species known as pollutants like carbon monoxide (CO), nitrogen oxides (NOx) and hydrocarbons, - often related to fossil fuel or biomass burning -, also affect climate through their role in chemical reactions that produce tropospheric ozone, which is a well-known greenhouse gas, or that modify the lifetime of gases like methane, or the oxidation capacity of the atmosphere.
Therefore in AGACC, we have focused on the measurement of a number of trace gases that are subject to changing concentrations, that directly or indirectly affect climate, and that are either difficult to monitor or that have not yet been measured from the ground. We have included attempts to observe distinctly some isotopologues, because the isotopic ratios observed in an airmass provide information on its history, and because the FTIR solar absorption measurements provide a rather unique capability hereto.
The investigated species are the isotopologues of CH4 and CO, and hydrogen cyanide (HCN), as examples of biomass burning tracers, some hydrocarbons like formaldehyde (HCHO), ethylene (C2H4) and acetylene (C2H2), and HCFC-142b, a replacement product for CFCs and a greenhouse gas.
In many cases, retrieval strategies had to be adapted when going from one site to another with different atmospheric conditions, especially when the local humidity and abundances are very different as is the case between Jungfraujoch (dry, high altitude, mid-latitude) and Ile de La Réunion (humid, low altitude, low latitude). Still we have been able to show the feasibility of retrieving particular trace gas information even under difficult conditions. Many of our results have been compared to correlative data, to validate the approach and to gain complementary information. It is also important to note that the retrieval strategies developed in AGACC have regularly been presented to the global Network for the Detection of Atmospheric Composition Change (NDACC) UV-Vis and Infrared communities and have often been adopted by others or even proposed for adoption as a standard in the community (e.g., for hydrogen cyanide (HCN)).
In particular:
We have been able to study the seasonal variations of HCN at the Jungfraujoch and at Ile de La Réunion, and to show the dominant impact of biomass burning. Formaldehyde was studied in much detail at Ukkel, Jungfraujoch and Ile de la Réunion. The challenge for detection at Jungfraujoch is the small abundance (about 10 times smaller than at Ukkel and Ile de La Réunion); a particular observation strategy was developed successfully, resulting in a time series that already shows the day-to-day and seasonal variations. At Ile de La Réunion, comparisons of FTIR, MAXDOAS, satellite and model data have (1) shown the good agreement between the various data sets, but also, (2), the variability of HCHO (diurnal, seasonal, day-to-day), and (3), thanks to the complementarities of the various data sets, they have enabled us to learn more about the long-range transport of Non-methane Volatile Organic Compounds (NMVOCS, precursors of HCHO) and deficiencies in the models. It was shown that fast, direct transport of NMVOCS from Madagascar has a significant impact on the HCHO abundance and its variability at Ile de La Réunion, and that this is underestimated in the model.
Significant progress was made as to the detection of 13CH4 and CH3D from ground-based FTIR observations, both at Jungfraujoch and Ile de La Réunion. To our knowledge, it is the first time that a d13C data set is derived from ground-based FTIR observations. More work is needed to improve the CH3D retrieval at Ile de La Réunion, and to interpret the results, in combination with models.
Also for the first time, 12CO and 13CO have been retrieved individually at Jungfraujoch. The d13C time series shows significant seasonal and interannual changes.
As to the hydrocarbon ethylene, it is shown that it can be detected at Jungfraujoch only in spectra at low solar elevation, given its small atmospheric abundance.
Regarding acetylene, the observed time series at Jungfraujoch and Ile de La Réunion show clear seasonal variations and enhancements due to the impact of biomass burning events, correlated with enhancements in CO, C2H6 and HCN.
It is not clear yet whether we can reliably retrieve the concentration of HCFC- 142b, a replacement product that is increasing strongly in the troposphere. New line parameters for the interfering species HFC-134a are required to confirm/infirm the preliminary results. This highlights again the importance of the laboratory work for providing such parameters.
Improved line parameters have been obtained for water vapour and its isotopologues, ethylene and formic acid. These AGACC results have been integrated in the international spectroscopic databases. We also showed that line intensities available around 2096 cm–1 for the 13C16O isotopologue of carbon monoxide in the HITRAN database seem to be accurate to 2%. We failed to improve line intensities for the 13.6 μm region of acetylene.
The new data sets that have been derived in AGACC from FTIR and MAXDOAS observations have been archived in the NDACC data centre, where they are available for users (generally modelers and satellite teams). In addition, they are stored locally and are available to users upon request.
AGACC results have been reported to the international scientific community, via the literature, via integration in geophysical or spectroscopic databases, and via participation to international research initiatives like the Atmospheric Water Vapour in the Climate System (WAVACS) Cost Action, the International Space Science Institute (ISSI) Working Group on Atmospheric Water Vapour, the International Union of Pure and Applied Chemistry (IUPAC) project, the International CINDI campaign, etc.
The results have already found important scientific applications. A few examples are worth mentioning: the re-evaluation of methane emissions in the tropics from SCIAMACHY based on the new H2O spectroscopy, and the improved retrievals of HCOOH from the satellite experiments ACE-FTS and IASI, and from the ground.
In the longer-term, the AGACC results will no doubt benefit the research in atmospheric sciences –in particular in the monitoring of its composition changes–, which is the fundamental basis of environmental assessment reports for supporting policy makers.Advanced exploitation of ground-based measurements for atmospheric chemistry and climate applications "AGACC
Technical Note: New ground-based FTIR measurements at Ile de La Réunion: observations, error analysis, and comparisons with independent data
Ground-based high spectral resolution Fourier-transform infrared (FTIR) solar absorption spectroscopy is a powerful remote sensing technique to obtain information on the total column abundances and on the vertical distribution of various constituents in the atmosphere. This work presents results from two FTIR measurement campaigns in 2002 and 2004, held at Ile de La Réunion (21° S, 55° E). These campaigns represent the first FTIR observations carried out at a southern (sub)tropical site. They serve the initiation of regular, long-term FTIR monitoring at this site in the near future. To demonstrate the capabilities of the FTIR measurements at this location for tropospheric and stratospheric monitoring, a detailed report is given on the retrieval strategy, information content and corresponding full error budget evaluation for ozone (O3), methane (CH4), nitrous oxide (N2O), carbon monoxide (CO), ethane (C2H6), hydrogen chloride (HCl), hydrogen fluoride (HF) and nitric acid (HNO3) total and partial column retrievals. Moreover, we have made a thorough comparison of the capabilities at sea level altitude (St.-Denis) and at 2200 m a.s.l. (Maïdo). It is proved that the performances of the technique are such that the atmospheric variability can be observed, at both locations and in distinct altitude layers. Comparisons with literature and with correlative data from ozone sonde and satellite (i.e., ACE-FTS, HALOE and MOPITT) measurements are given to confirm the results. Despite the short time series available at present, we have been able to detect the seasonal variation of CO in the biomass burning season, as well as the impact of particular biomass burning events in Africa and Madagascar on the atmospheric composition above Ile de La Réunion. We also show that differential measurements between St.-Denis and Maïdo provide useful information about the concentrations in the boundary layer.Peer reviewe
Fourier transform measurements of water vapor line parameters in the 4200–6600cm−1 region
Composition, propriétés et comportement des aérosols atmosphériques, des brouillards, des rosées et des pluies en région bruxelloise
La pollution atmosphérique en milieu urbain est un problème préoccupant car une fraction croissante de la population mondiale vit dans les villes. Les effets de la pollution se manifestent également sur la végétation urbaine et sur notre patrimoine architectural, de sorte que c'est la qualité de la vie de l'ensemble des habitants des métropoles de la planète qui est en jeu. Il est indispensable de connaître la composition des atmosphères urbaines et de comprendre les mécanismes qui régissent cette composition pour évaluer les conséquences de la pollution, définir les exigences de réduction des émissions et établir des scénarios des tendances futures.<p><p>L'objectif du présent travail est de déterminer la composition chimique, les propriétés et le comportement des particules et des dépôts humides en Région bruxelloise. On a distingué les aérosols atmosphériques, les brouillards, les rosées (ou givres) récoltés à la fois sur les végétaux et sur un collecteur inerte, les pluies et les dépôts totaux (formés des pluies et des dépôts secs accumulés dans l'entonnoir de collecte en l'absence de pluie). Ce vaste objectif a été réalisé grâce à la collecte de nombreux échantillons sur une échelle de temps suffisante en différents endroits de la capitale, et à l'analyse de ces échantillons par des techniques variées et complémentaires (techniques classiques d'analyse d'échantillons liquides telles que spectrométrie d'absorption et d'émission atomique, chromatographie liquide, colorimétrie, ainsi que microscopie électronique et fluorescence des rayons-X). Trois collecteurs (pour le brouillard, la pluie et la rosée) ont été entièrement conçus et réalisés au laboratoire dans le cadre de ce travail. Les éléments suivants sont analysés: NO3, SO4, NH4, Na, Mg, Al, Si, P, S, CI, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Cd, Pb.<p><p>Afin de comprendre les causes de la variabilité spatio-temporelle des concentrations, l'influence de paramètres tels que la saison, la direction du vent, et le lieu de prélèvement a été examinée. De plus, dans le cas des pluies et des brouillards, l'étude de l'évolution des concentrations au cours d'un même épisode a permis d'investiguer les processus physico-chimiques qui contrôlent le dépôt humide. Elle a permis d'acquérir une meilleure connaissance des mécanismes d'incorporation des aérosols dans la phase aqueuse et du phénomène de lessivage de l'atmosphère. Tout au long de ce travail, les interactions entre la phase particulaire (aérosols) et les phases liquides (brouillards, rosées, pluies) ont été examinées. Une relation entre les concentrations en éléments dissous et le volume d'eau de l'échantillon a été établie dans le cas des pluies, des rosées et des brouillards. Cette relation traduit un effet de dilution et démontre l'importance du mécanisme de condensation-évaporation des gouttes d'eau. L'importance du phénomène de nucléation des sulfates, nitrates et chlorures d'ammonium constitutifs de la fraction fine de l'aérosol soluble a été démontrée. Ces sels d'ammonium sont formés secondairement par des réactions de conversion gaz-particules. L'abondance des ions ammonium, et l'importance de leur action de neutralisation de l'acidité, constituent une particularité de l'atmosphère bruxelloise.<p>L'identification des sources de particules et d'éléments en relation avec leurs propriétés chimiques et granulométriques a été réalisée en utilisant divers outils statistiques (corrélations entre éléments, analyse factorielle) et géochimiques (rapports de concentration, facteurs d'enrichissement, granulométrie). Les apports d'origine marine, continentale, biologique et anthropique (trafic, incinération des déchets, processus de combustion) ont ainsi été clairement mis en évidence dans l'aérosol et le brouillard bruxellois.<p>Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe
De BA1 à MA2, que de changements, d’évolutions, de différences !
Comment évolue l’esprit critique des étudiants tout au long de leur cursus ?Afin de brosser le tableau de leur degré d’esprit critique sous différents plans, je m’attacherai, à travers des exemples concrets, à comparer leurs profils, leurs niveaux de connaissance en matière d’utilisation des ressources, de citation, plagiat, outils de navigation, …, ainsi que leurs attentes, et degrés d’autonomie. Par exemple, comment considèrent-ils Google, comment appréhendent-ils la problématique du plagiat, comment jugent-ils de la fiabilité et de la pertinence d’un document ?Mon expérience personnelle auprès d’étudiants se situant aux différents niveaux du cursus permet d’évoquer ces matières, avec comme corollaire, quelle pierre à l’édifice puis-je leur apporter en tant que formatrice à la recherche documentaire ?info:eu-repo/semantics/publishe
UV Fourier transform absorption cross sections of benzene, toluene, meta-, ortho-, and para-xylene
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Fourier transform measurements of SO2 absorption cross sections: I. Temperature dependence in the 24 000-29 000 cm-1 (345-420 nm) region
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Fourier transform measurements of SO2 absorption cross sections: II. Temperature dependence in the 29 000-44 000 cm-1 (227-345 nm) region
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