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Analyzing tree-growth response, past hydroclimate variability and related geohazard activities in the Western Himalayas using dendroecological and dendrogeomorphological approaches
No full textThe inevitable climate change will have significant long-term impact on the Earth’s natural ecosystem and human civilization over the world. The unprecedented global warming observed since the last century and warming trend predicted by climate models, alarms the future availability of fresh water and other ecosystem services for human livelihood. The Himalayan arc, which hosts diverse ecosystems under different hydroclimatic regimes, is highly susceptible to climate change with a warming rate higher than the global average. The impact of temperature rise in the Himalayan region is evident by the monitored high rates of glacier retreats, tree-line shifts, changes in vegetation composition, phenology, species distribution, and in addition by a significant rise in extreme weather events and related geohazard episodes. The western Himalayan climate exhibits a complex interplay of western disturbances (WDs) and south Asian summer monsoon (SASM) controlling the hydrology, ecosystem and livelihood over the region. Meteorological records show an inverse relationship between WD and SASM circulation intensity, and their connectivity with other climatic circulations operating in the north Atlantic, the tropical Pacific and the Indian Ocean regions. However, the limited geographical coverage of meteorological stations with instrumental data not before the 20th century restricts our understanding of the behaviour of these interconnected climatic circulations beyond the meteorological records. The long-term quantification of these climatic processes is thus needed to extend the present meteorological records for a robust understanding of climate processes on regional to local level, and their impact on biodiversity. Although a number of climate reconstructions are available from the Himalayan region, large knowledge gaps still exist on the annually to intra-annually resolved climate in time and space. Tree-rings are the best archives preserving the evidences of ongoing climatic and non-climatic processes of regional and local scale. This dissertation presents the contribution and interconnection of three independent studies on the tree-growth dynamics, climate reconstructions, and geohazard activity analysis in relation to climate from sites located in different hydroclimatic regimes of the western Himalayas.
The first study in chapter 2 entitled “Tree-ring oxygen isotope variations in subalpine Firs from the Western Himalaya capture spring season temperature signals” focuses on the growth response of Abies spectabilis (Fir) at subalpine altitudes in the SASM dominated region of the western Himalayas. Here, a developed 60 year-long (1960–2019 CE) tree-ring δ18O chronology was found to be strongly sensitive to temperatures, snow-cover, soil-moisture and relative humidity of late winter and spring months (February to April). The spatial correlation with sea surface temperatures (SSTs) and climate indices identified an influence of the North Atlantic Oscillation (NAO) with subdued effects of tropical Pacific circulations. At the subalpine site, the winter snow fed soil-moisture and spring months’ temperature modulates the 18O fractionation in the trees during photosynthesis. Moreover, the “amount effect” of summer precipitation is found to be too weak to override the spring temperature signals at the subalpine altitudes.
Chapter 3 entitled “Himalayan silver fir reveals moist phase during Little Ice Age in the Kashmir region of the western Himalayas” focusses on the region under the influence of winter precipitation by WD circulations. A 461 year-long (1555-2016 CE) tree-ring width chronology (TRWC) of Abies pindrow (silver Fir) covers the time span of Little Ice Age (LIA) climate anomaly. The tree growth-climate relationship revealed a coupled response of temperature and moisture of spring and summer months (April-June) significant for Fir radial growth. The moisture reconstruction using the self-calibrated Palmer drought severity index (scPDSI) for the period 1643-2016 CE was able to identify wet and dry phases corresponding to the respective LIA and post-LIA periods. Further analysis showed the significant impact of the Atlantic Multi-decadal Oscillation (AMO) and NAO with a strong westerly circulation pattern for the wet LIA phase, and a subsequent weakening of WD strength during the 19th and 20th century.
The third study in chapter 4 put forth “Past drought reconstruction and related dendrogeomorphic time-series analysis from Kinnaur region of western Himalayas”. This study site located in the WD and SASM transient region also presents a 463 year-long (1558-2021 CE) Tree ring width chronology of Cedrus deodara (Deodar or Cedar) covering the LIA period. The late winter and spring months (FMA) moisture are important for deodar growth in the region. The 364 years reconstruction of the standardized precipitation evapotranspiration index (SPEI04) revealed a phase of high moisture variability corresponding to the LIA and a subsequent dry post-LIA phase. The climate modes AMO and NAO show a strong influence during the 18th century, whereas El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) impacted the study area during the 19th and 20th century. In a pioneer attempt, past geohazard episodes are reconstructed for the Himalayan region using dendrogeomorphological approach. Reconstructed rockfall activities correspond with years of dry spring and summer months.
This PhD dissertation synthesizes the outcomes of studies from three sites discussing on the established tree-ring width and tree-ring δ18O chronologies, tree-growth response, long-term hydroclimatic trend and their driving mechanisms on a regional perspective over the western Himalayas. The studies captured the variability in the tree-growth sensitivity to climate showing influence of geographical position and elevation. Importantly, this endeavor presents two TRWC based hydroclimate reconstruction covering the LIA time frame which is still less understood for its inter- and intra-annual hydroclimate dynamics over the Himalayas. The correlation amongst the reconstructed long-term hydroclimatic trends from two sites reflects the dynamics of WD and SASM circulations at regional and local spatial scale. Moreover, the pioneer attempt of geohazard analysis using tree-rings at one study site has provided insight on the relationship between climate and geohazard activities. The generated datasets will help append the available proxy records and also complements the meteorological stations to fill the spatial climate data gaps in the region. Moreover, the research findings could help managers and decision-makers in sustainable management of forests, land-use, water resources, and towards geohazard risk management and mitigation.Der nachweisliche Prozess des Klimawandels hat in langfristiger Perspektive erhebliche Auswirkungen auf die natürlichen Ökosysteme der Erde und die menschliche Zivilisation. Die seit dem letzten Jahrhundert zu beobachtende beispiellose globale Erwärmung und die von Klimamodellen vorhergesagte Erwärmungstendenz bedrohen die zukünftige Verfügbarkeit von Süßwasser und anderen Ökosystemdienstleistungen. Der Himalaya mit seinen unterschiedlichen hydroklimatischen Verhältnissen und vielfältigen Ökosystemen ist aufgrund der im globalen Vergleich hohen Erwärmungsraten hochgradig gegenüber dem Klimawandel anfällig. Die Auswirkungen des Temperaturanstiegs im Himalaya äußern sich dabei in einem beobachteten, starken Gletscherrückgang, einer Verschiebung der Baumgrenze, an Veränderungen in der Vegetationszusammensetzung, der Phänologie und der Artenverteilung sowie in einer signifikanten Zunahme extremer Wetterereignisse und damit verbundener Naturereignisse.
Das Klima der westlichen Himalaya-Region weist ein komplexes Zusammenspiel von westlichen Störungen (WD) und dem südasiatischen Sommermonsun (SASM) auf, der die Hydrologie, das Ökosystem und die Lebensgrundlagen in der Region kontrolliert. Meteorologische Aufzeichnungen zeigen eine umgekehrte Beziehung zwischen der Zirkulationsintensität der WD und des SASM sowie deren Verbindung mit anderen klimatischen Zirkulationsmustern im Nordatlantik, im tropischen Pazifik und im Indischen Ozean. Die begrenzte Verfügbarkeit von meteorologischen Stationen und dort aufgezeichneter Klimadaten, die zudem nicht vor dem 20. Jahrhundert zur Verfügung stehen, schränkt jedoch das Verständnis für die Konnektionen dieser miteinander verbundenen Klimazirkulationen signifikant ein.
Eine langfristige Quantifizierung von Klimaprozessen ist daher notwendig, um sie mit meteorologischen Aufzeichnungen zu erweitern und dadurch ein solides Verständnis der Klimadynamik auf regionaler bis lokaler Ebene sowie der damit verbundenen Auswirkungen auf die biologische Vielfalt zu erlangen. Obwohl einige Klimarekonstruktionen aus der Himalaya-Region zur Verfügung stehen, gibt es nach wie vor große Wissenslücken bezüglich des jährlichen bis intra-jährlichen Klimas in Zeit und Raum. Jahrringe sind das bestgeeignete Klima-Archiv, das nachweislich Informationen zu aktuellen und vergangenen klimatischen und nichtklimatischen Prozessen auf regionaler und lokaler Ebene beinhalten. Diese Dissertation stellt den Beitrag und die Verbindung dreier unabhängiger Studien über die Dynamik des Baumwachstums, Klimarekonstruktionen und die Analyse von Naturgefahren im Zusammenhang mit der Klimadynamik an Standorten mit unterschiedlichen hydroklimatischen Regimen des westlichen Himalaya vor.
Die erste Studie in Kapitel 2 mit dem Titel „Tree-ring oxygen isotope variations in subalpine Firs from the Western Himalaya capture spring season temperature signals“ konzentriert sich auf die Wachstumsreaktion von Abies spectabilis (Tanne) in subalpinen Höhenlagen in der SASM-dominierten Region des westlichen Himalaya. Es wurde festgestellt, dass eine über 60 Jahre (1960-2019 n. Chr.) lange δ18O-Chronologie von Baumringen stark auf die Temperaturen, die Schneedecke, die Bodenfeuchtigkeit und die relative Luftfeuchtigkeit der späten Winter- und Frühlingsmonate (Februar bis April) reagiert. Die räumliche Korrelation mit den Meeresoberflächentemperaturen (SST) und den Klimaindizes zeigt den Einfluss der Nordatlantischen Oszillation (NAO) mit einer gedämpften Wirkung der tropischen pazifischen Zirkulationen. In den subalpinen Regionen, modulieren die durch Schnee gespeiste Bodenfeuchtigkeit im Winter und die Temperatur in den Frühlingsmonaten die 18O-Fraktionierung in den Bäumen während der Photosynthese. Darüber hinaus wurde festgestellt, dass der „Mengeneffekt“ des Sommerniederschlags zu schwach ist um die Temperatursignale des Frühjahrs in den subalpinen Höhenlagen zu überlagern.
Kapitel 3 mit dem Titel „Himalayan silver fir reveals moist phase during Little Ice Age in the Kashmir region of the western Himalayas“ dar, die sich auf die Region unter dem Einfluss von Winterniederschlägen durch WD-Zirkulationen konzentriert. Eine 461 Jahre lange (1555-2016 n. Chr.) Baumring-Breiten-Chronologie (TRWC) basierend auf Abies pindrow (Weißtanne) deckt die Zeitspanne der Klimaanomalie der Kleinen Eiszeit (LIA) ab. Die Beziehung zwischen Baumwachstum und Klima zeigte eine gekoppelte Reaktion von Temperatur und Feuchtigkeit in den Frühlings- und Sommermonaten (April-Juni), die für das radiale Wachstum der Tanne von Bedeutung ist. Die Feuchtigkeitsrekonstruktion unter Verwendung des selbstkalibrierten Palmer-Dürre-Schwere-Index (scPDSI) für den Zeitraum 1643-2016 n. Chr. konnte feuchte und trockene Phasen identifizieren, die den jeweiligen LIA- und Post-LIA-Zeiträumen entsprechen. Weitere Analysen zeigten, den straken Einfluss der Atlantischen Multidekadischen Oszillation (AMO) und die NAO mit starken WD-Zirkulationen für die feuchte LIA-Phase und eine anschließende Abschwächung der WD-Stärke während des 19. und 20.
Die dritte Studie in Kapitel 4 befasst sich mit der Rekonstruktion der Trockenheit und der damit verbundenen dendrogeomorphen Zeitreihenanalyse in der Region Kinnaur im westlichen Himalaya. An diesem Studienort, der in der gemeinsamen WD- und SASM-Region liegt, wurde eine 463 Jahre (1558-2021 n. Chr.) dauernde Jahrringbreitenchronologie aus Cedrus deodara Bäumen (Deodar-Zeder) generiert, die damit den Zeitraum der LIA abdeckt. Die Feuchtigkeit in den späten Winter- und Frühlingsmonaten (FMA) ist hierbei von hoher Bedeutung für das Wachstum der Deodar-Zeder in der Region. Die 364-jahre umfassende Rekonstruktion mit Hilfe des standardisierten Niederschlags-Evapotranspirations-Index (SPEI04) zeigt ebenfalls eine Phase hoher Feuchtigkeitsvariabilität, die der LIA und einer daran anschließenden trockeneren Klima-Phase entspricht. Im 18. Jahrhundert beeinflussen die Klimamodi AMO und NAO und im 19. und 20 Jahrhundert die El Niño-Southern Oscillation (ENSO) und Pacific Decadal Oscillation (PDO) die Region nachhaltig. In einem Pionierversuch wurden darauf aufbauend vergangene Geohazard-Episoden in der Himalaya-Region mithilfe eines dendrogeomorphologischen Ansatzes rekonstruiert. Die darin rekonstruierten Steinschlagaktivitäten stimmen dabei mit Jahren mit eher trockenen Frühlings- und Sommerbedingungen überein.
Die Dissertation beinhaltet somit zusammenfassend die Ergebnisse von drei thematisch individuellen Studien von drei verschiedenen Regionen im westlichen Himalaya, in denen etablierten Jahrringbreiten und δ18O-Chronologien, die Reaktion des Baumwachstums, der langfristige hydroklimatische Trend und ihre Antriebsmechanismen aus regionaler Sicht erörtert wurden. In den Studien wurde die Variabilität der Empfindlichkeit des Baumwachstums gegenüber dem Klima erfasst, wobei der Einfluss der geografischen Lage und der Höhenlage deutlich wurde. In diesem Projekt werden zwei TRW-basierte Rekonstruktionen des Hydroklimas vorgestellt, die den LIA-Zeitraum abdecken, dessen inter- und intra-annuelle Hydroklimadynamik über dem Himalaya noch wenig verstanden ist. Die Korrelation zwischen den rekonstruierten langfristigen hydroklimatischen Trends von zwei Standorten zeigt die Dynamik der WD- und SASM-Zirkulationen auf regionaler und lokaler räumlicher Ebene. Darüber hinaus hat der Pionierversuch einer Georisikoanalyse mit Hilfe von Baumringen an einem Studienstandort einen Einblick in die Beziehung zwischen Klima und Georisikoaktivitäten gegeben. Die erzeugten Datensätze werden dazu beitragen, die verfügbaren Proxy-Datensätze zu ergänzen und die meteorologischen Stationen zu vervollständigen, um die räumlichen Klimadatenlücken in der Region zu schließen. Darüber hinaus könnten die Forschungsergebnisse den Managern und Entscheidungsträgern bei der nachhaltigen Bewirtschaftung von Wäldern, Landnutzung und Wasserressourcen sowie beim Risikomanagement und der Risikominderung von Georisiken helfen
Going Beyond Counting First Authors in Author Co-citation Analysis
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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
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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
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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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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