1,721,235 research outputs found
Comparison of the O3 chemistry in the Po Valley with that in the Benelux region as simulated with MECO(n)
Get PDFNon-traffic (i.e. households, industry, etc.) emissions and land transport emissions are important anthropogenic precursors of tropospheric O3 and affect the air quality and contribute to global climate change. In order to improve air quality and mitigate climate change, robust knowledge of the amount of O3 formed by different emission sources is required. This study investigates the contributions of the different emission sectors to the ground-level ozone budget in Europe and Southeast Asia. For the present study we applied the MECO(n) model system, which couples the global chemistry-climate model EMAC on-line with the regional chemistry-climate model COSMO-CLM/MESSy. We used MECO(n) with a source apportionment method for ozone to investigate regional differences of the contributions from different emissions to ground-level ozone. Our findings show that contributions from anthropogenic non-traffic emissions to ground-level ozone are larger in Southeast Asia than in Europe. The contrary applies for the land transport emissions, which are more important in Europe compared to Southeast Asia
johannespletzer/rf-of-hypersonic-trajectories: First public release v1.0-doi
No full text<p><strong><span>Radiative forcing of hypersonic aircraft emission inventories</span></strong></p>
<p><strong><span></span></strong><span>The software quantifies climate impact of hypersonic aircraft emission inventories as a number and within seconds instead of very long numerical simulations that produce Petabytes of data. The input requires water vapor, hydrogen and nitrogen oxide emission data along flight trajectories.</span></p>
<p><span>The repository provides a Python package, examples and an executable to calculate the climate impact (stratosphere adjusted radiative forcing) of hypersonic aircraft emission inventories. The radiative forcing of water vapour changes and ozone changes are calculated on the basis of water vapour, hydrogen and nitrogen oxide emissions. <br></span></p>
<p><strong><span>Limitations</span></strong></p>
<p><span>Interpolation (30-38 km) and extrapolation surface-30 km are used. It is recommended to note the following:</span></p>
<ul>
<li><span>The atmospheric and radiative sensitivites are based on results from [Pletzer et al (2024)](https://acp.copernicus.org/articles/24/1743/2024/). The atmospheric composition of the numerical climate model is based on surface emission inventories for 2050. </span></li>
<li><span>The class includes a function (`drop_vertical_levels()`) that drops emission in the troposphere or below specified altitude levels and excludes it from the climate calculation. Its use is strongly recommended as long as sensitivities are not yet extended to altitudes below 30 km.</span></li>
<li><span>The climate impact of emission inventories where the average flight altitude does not correspond to the typical hypersonic flight altitudes (about 24-40 km) should not be estimated.</span></li>
<li><span>Meaningful results can be expected for the radiative effect of water vapour changes due to water vapour emissions. This explicitly excludes the radiative effect of water vapour changes due to hydrogen and nitrogen oxide emissions.</span></li>
<li><span>Meaningful results can be expected for the radiative effect of ozone changes due to water vapour, hydrogen and nitrogen oxide emissions.</span></li>
</ul>
<p><span>Please keep these limitations in mind when using the software.</span></p>
<p><strong><span>Python environment requirements</span></strong></p>
<p><span>The software requires various functions from the following python modules:</span></p>
<ul>
<li><span>numpy</span></li>
<li><span>pandas</span></li>
<li><span>xarray</span></li>
<li><span>scipy</span></li>
<li><span>xlsxwriter</span></li>
<li><span>netcdf4</span></li>
<li><span>aerocalc3</span></li>
</ul>
<p><span> </span><span>Install the required packages with <code>pip install numpy pandas xarray scipy xlsxwriter netcdf4 aerocalc3</code></span></p>
<p><strong><span>Getting started</span></strong></p>
<p><span>The repo contains two example notebooks for processing of emission inventories in mat- and nc-format. Otherwise, the user can run the main.py executable which reads all emission inventory files within the folder and returns the calculated radiative forcing in an xlsx file. Execute main.py with `python3 main.py <path_to_your_emission_files>`. Please contact Johannes Pletzer for any questions.</span></p>
<p><strong><span>Code quality</span></strong></p>
<p><span>The code was formatted according to PEP 8 style with the help of the modules 'flake8', 'isort', 'pylint' and 'black'.</span></p>
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Finding the climate optimal cruise altitude for a selection of aircraft types and mission combinations
No full textThe climate impact of aviation is assessed as function of the emission altitude for two different aircraft types, the Boeing 787-800 and Boeing 777-300ER. The basis for this research is an assembly of 2,738 historical trajectories for which the fuel consumption and emissions were determined by using Piano-X aircraft performance data and atmospheric weather data from the European Centre for Medium-Range Weather Forecasts. The resulting emissions served as input for the climate response model AirClim which calculated the resulting climate response over time. To analyze the effect of changes in cruise altitude, the fuel consumption and corresponding emissions were recalculated for scenarios with relocated cruise altitude profiles ranging from an upward shift of 2000 ft to a downward shift of 18000 ft with respect to the original cruise altitude. By shifting cruise altitudes down, the total climate impact was found to be reduced for both aircraft types where the minimal climate impact is found for the lowest analyzed cruise altitude. The reduction in climate impact is mainly the result of the reduced short term forcings from contrail cirrus, ozone and the induced destruction of methane where their individual contribution to the total climate impact reduction was found to be dependent on aircraft type. Relocating cruise altitudes up was found to increase the climate impact for both aircraft types.Aerospace Engineerin
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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