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Sources and sinks of stratospheric water vapor
Get PDFA tutorial review of the understanding of stratospheric H/sub 2/O and the processes controlling it is presented. Paradoxes posed by currently available observational data are cited and suggestions made as to how they might be resolved. Such resolution appears to require: that the bulk of our current data provides unrepresentative and misleading vertical and latitudinal H/sub 2/O gradients immediately downstream from the tropical tropopause; and, that there exists within the troposphere a mechanism different from or in addition to the tropical tropopause cold trap for drying air to the mixing ratios found in the lower stratosphere. Satisfaction of these requirements will reconcile much heretofore puzzling observational data and will obviate the necessity for a stratospheric sink for H/sub 2/O
A different view of the climatic effect of CO2 Updated
No full textAn update is given of a previous paper by the same title, an explanation is given of the way greenhouse gases operate to raise the surface temperature of a planet. The paper in general is designed to be understandable to a wide range of disciplines. The argument is advanced that the role of radiative transfer has been overemphasized relative to other climatological processes and, in particular, that the roles of deep convection in the tropics and of evaporation from tropical oceans have been underemphasized and inadequately modeled in our calculations of climatic effects of increased CO2 to date.SE PRESENTA UNA VERSION NUEVA DE UN ARTÍCULO ANTERIOR DEL MISMO TITULO, Y SE DA UNA EXPLICACION DE LA FORMA EN QIUE GASES DE INVERNADERO OPERAN EN LA ELEVACION DE LA TEMPERATURA SUPERFICIAL DE UN PLANETA. EL ARTÍCULO, EN GENERAL, ESTA DISEÑADO PARA QUE SEA COMPRENDIDO POR UNA GAMA GRANDE DE ESPECIALISTAS. SE ADELANTA EL ARGUMENTO DE QUE EL PAPEL DE LA TRANSFERENCIA DE RADIACION HA SIDO SOBREESTIMADO EN RELACION AOTROS PROCESOS CLIMATOLOGICOS; EN PARTICULAR AQUELLOS QUE SE REFIEREN A LA CONVECCION PROFUNDA EN LOS TROPICOS Y A LA EVAPORACION EN LOS OCEANOS TROPICALES HAN SIDO SUBESTIMADOS E INADECUADAMENTE MODELADOS EN NUESTROS CALCULOS DEL EFECTO CLIMATICO DEL AUMENTO HASTA NUESTROS DIAS DE CO2
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Atmospheric carbon dioxide and the climate record
Get PDFThis paper is an attempt to provide a summary review of conclusions from previous studies on this subject. Subject headings include: conceptualization of the greenhouse effect, the climatic effect of doubled CO/sub 2/, interpretation of the climatic record, diagnosis of apparent and possible model deficiencies, and the palaeoclimatic record
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Response to W. W. Kellogg carbon dioxide and climatic change: implications for mankind's future
Get PDFThe writer objects to the consensus that doubled CO/sub 2/ levels will lead to a global temperature increase of 3/sup 0/C and the associated implications for mankind. In this paper he presents his reasons for doubting the majority view on two climatic feedback processes: (1) the ice-albedo feedback, and (2) the water vapor feedback. (ACR
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Stratospheric H/sub 2/O
No full textDocumentation of the extreme aridity (approx. 3% relative humidity) of the lower stratosphere and the rapid decrease of mixing ratio with height just above the polar tropopause (20-fold in the 1st km) was begun by Dobson et al., (1946) in 1943. They recognized that this extreme and persistent aridity must be dynamically maintained else it would have been wiped out by turbulent diffusion. This led Brewer (1949) to hypothesize a stratospheric circulation in which all air enters through the tropical tropopause where it is freeze dried to a mass mixing ratio of 2 to 3 ppM. This dry air then spreads poleward and descends through the polar tropopauses overpowering upward transport of water vapor by diffusion which would otherwise be permitted by the much warmer temperatures of the polar tropopauses. Questions can indeed be raised as to the absolute magnitudes of stratospheric mixing ratios, the effective temperature of the tropical tropopause cold trap, the reality of winter pole freeze-dry sinks and the representativeness of the available observations suggesting an H/sub 2/O mixing ratio maximum just above the tropical tropopause and a constant mixing ratio from the tropopause to 30 to 35 km. However, no model that better fits all of the available data is available, than does the Brewer (1949) hypothesis coupled with a lower stratosphere winter pole, freeze-dry sink, at least over Antarctica. (JGB
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Man's effect on stratospheric ozone
Get PDFSince McDonald, at the beginning of this decade, first proposed that water vapor from SST exhaust would lead to increases in skin cancer, about a dozen man-induced mechanisms have been suggested as threatening to modify our stratospheric ozone uv-shield. Possible thinning of the ozone layer has been attributed to one or more of the catalytic ozone destroyers, water vapor (HO/sub x/), oxides of nitrogen (NO/sub x/), chlorine (ClX); or bromine (BrX). The original catalyst, HO/sub x/, rather quickly lost its role to NO/sub x/. In an almost unique evolution, computed sensitivity of stratospheric ozone to NO/sub x/ progressively declined until a reversal of effect occurred. Models now compute a thickening of the ozone layer for any but high level or very massive injections of NO/sub x/. Meanwhile, computed sensitivity to ClX has fluctuated widely and in 1978 models increased to the point where comparisons with observations were becoming an embarrassment. The potential role of BrX has also increased but awaits a credible source of stratospheric bromine to bring it center stage. More recently the atmospheric build-up of carbon dioxide, by cooling the stratosphere and increasing the chemical equilibrium level of ozone, has also been recognized as a potential modifier of the ozone layer
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
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
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