1,720,969 research outputs found
Efficacy of Solar irradiance, Methane and Black carbon aerosols
No full textIn climate science literature, the concept of radiative forcing is used to infer the equilibrium temperature change that would occur as a result of changes in the forcing agents such as greenhouse gases and aerosols. Radiative forcing is defined as the energy imbalance that occurs at the top-of-atmosphere because of the imposed changes in the forcing agents. It would be a useful quantity to compare the importance of various forcing agents if the climate system response depends on the radiative forcing and not on the forcing agents. However, recent studies show that the climate system response depends on the forcing agents to some extent.
In order to address this issue, the concept of ‘efficacy’ of forcing agents was introduced. Efficacy is the ratio of the equilibrium global mean surface temperature change per unit forcing from an agent to the equilibrium temperature change per unit carbon-dioxide (CO2) forcing from the same initial climate state. An efficacy of one implies that two forcing agents that induces same radiative forcing would produce same global mean temperature response while a non-unity efficacy would indicate different temperature response for same radiative forcing. Past studies investigated the efficacy of various forcing agents but a detailed assessment of the climate processes responsible for the efficacy to be different from one is lacking.
Using a global climate model, Community Atmosphere Model version 5 (CAM5) developed by the National Centre for Atmospheric Research (NCAR), we estimate the efficacy of three climate forcing agents - solar irradiance, methane (CH4) and black carbon (BC) aerosols and investigate the physical mechanisms responsible for a differing efficacy of these forcing agents compared to CO2. We also investigate and compare the hydrological cycle response to CO2 and these forcing agents. To compute the radiative forcing and efficacy, we adopt the Hansen’s prescribed-sea-surface-temperature (SST) and Gregory’s regression approaches. The recent Intergovernmental Panel on Climate Change (IPCC 2013) finds the radiative forcing estimated using these methods to be better predictor of global mean surface temperature change compared to other radiative forcing definitions.
This study is the first modelling study which provides a comprehensive assessment of the physical mechanisms responsible for a non-unity efficacy for solar irradiance, methane and black carbon aerosols. It also highlights the importance of including the efficacy factor in the “forcing and response” relationship for an improved estimate of surface temperature change due to a particular forcing agent. Further investigation using a multi-model intercomparison framework would permit an assessment of the robustness of the results shown in this study
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“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
Full text linkWe 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
Full text linkWe 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
The 2000-2012 global warming hiatus more likely with a low climate sensitivity
No full textThis dataset contains py codes, observational data, CMIP6 model data and AR6 ERF forcing used to produce figures of this paper. The respective figures are also uploaded in this dataset
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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