1,720,958 research outputs found
On the 2010 Anomalous Europe Blocking High and Wave Activity
No full text在2010年的夏天，東歐發生了俄羅斯熱浪，造成一萬多人死亡以及嚴重的經濟損失，屬於相當極端的熱浪。熱浪起因於在東歐影響整個夏季之阻塞高壓，噴流位置的改變也使的非洲的暖空氣容易進入東歐，創下高溫紀錄。此高壓在長期的百分位數上非常突出，因大氣提供良好的條件使阻塞生成及維持，分析後發現2010年瞬變渦流活動情形明顯，不僅阻塞上游渦流活躍，阻塞下游的活動情形更是突出，也顯示阻塞影響的範圍涵蓋整個歐亞大陸，瞬變渦流的活躍反映在能量轉換上，在阻塞上游能量由瞬變渦流轉換至平均流的情形顯著，E向量分析上也顯示這些能量輻合到阻塞區累積，使得阻塞有足夠的能量長期維持。而在駐波能量通量上則發現由北美及大西洋向東頻散的波列，並且在垂直上面發現顯著的由低層向高層頻散之通量，在阻塞發生處輻散，分成兩支向下游東南及東北方頻散，顯示能量可能來源除了北美及大西洋方向外，也有來自低層地表或海洋的作用。
這樣極端的阻塞現象，雖然有良好的大氣條件，但必有其他因素影響才可能發生，本研究目的為了解此極端現象之相關的因素，企圖找出維持阻塞長期籠罩東歐之影響因素，故由海溫著手，探究是否高海溫維持了此阻塞高壓，並利用ECHAM5模式做檢驗。
2010年的海溫有幾處相當的高，尤其是鄰近歐洲的熱帶、高緯度大西洋以及印度洋，皆超過95百分位數，以此海溫距平作為邊界驅動大氣環流模式，三實驗皆可以在東歐地區產生正的壓力距平，但程度遠小於實際情形，瞬變渦流與平均場的交互作用情形微弱，在大西洋兩實驗中，能量進入波導引發類似的波列，印度洋的實驗可能經由羅士培波源的引發，引發高壓及影響波列傳送。
本研究以大氣環流模式探究海溫對於東歐阻塞高壓的貢獻，結果顯示不論是大西洋海溫或者印度洋海溫，皆對東歐阻塞高壓有加強的貢獻，且印度洋的影響較大西洋來的強烈，但無法在模式中得到如實際般的極端情形。長期統計分析顯示東歐阻塞與熱帶大西洋和高緯大西洋海溫呈現顯著正相關，表示海溫是造成東歐擾動的重要因素，但2010年個案的極端強度則不是極端海溫異常可以單獨解釋。A series of severe heat waves, wildfires and droughts occurred in Eastern Europe in the 2010 summer. This dramatic event is also known as the 2010 Russian heat wave. Over 15,000 people lost their life in this event, and the economic loss was dramatic. A long-lasting blocking high that affected this region between June 20th and August 16th. The percentile analysis showed the 500hPa pressure in the region was the highest among the past 53 summers. Meanwhile, the sea surface temperature (SST) in parts of the North Atlantic was also found to be among the highest in the past 130 years. The possible effect of the anomalously high Atlantic SST anomaly (SSTA) on the Eastern European blocking high was explored in this study using the ECHAM5 AGCM.
Different initial conditions and resolutions were first tested in the simulations forced by the observed global SSTA. The observed high SSTA in the tropical and high-latitude Atlantic were prescribed as forcing to explore their relative influence. The results were sensitive to both the spatial resolution and initial condition. The T106 simulations with proper initial conditions were able to produce reasonable results, while all T63 simulations with or without proper initial condition failed to simulation the event. Both tropical and high-latitude SSTA experiments reasonably simulated the high-pressure anomaly in the Eastern Europe, however, the high-latitude SSTA experiment performed slightly better than the tropical SSTA one. The wave activity flux calculated from the model output showed that both SSTA experiments carried energy flux into waveguide. Thus, the pattern that simulated performed analogously.
India Ocean SSTA were also anomalous high in 2010 summer. The effect of the high SSTA was tested by same condition. The India ocean SSTA experiment may induce Rossby wave source near Mediterranean that cause a resembling wave pattern near East Europe. The result showed India ocean SSTA had more effect then the Atlantic SSTA.
The preliminary results suggest that the anomalously high SSTA in the Atlantic and India ocean could be partially responsible for the European blocking in the 2010 summer. However, the simulated amplitudes are smaller the observed. Such an experiment approach cannot explain the record-breaking amplitude and duration of this unusual event
Roles of European blocking and tropical-extratropical interaction in the 2010 Pakistan flooding
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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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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