No description available.

Finely laminated sediments within Bainbridge Crater Lake, Galapagos, provide a record of El Nino-Southern Oscillation (ENSO) events over the Holocene. Despite the importance of this sediment record, hypotheses for how climate variability is preserved in the lake sediments have not been tested. Here we present results of long-term monitoring of the local climate and limnology and a revised interpretation of the sediment record. Brown-green, organic-rich, siliciclastic laminae reflect warm, wet conditions typical of El Nino events, whereas carbonate and gypsum precipitate during cool, dry La Nina events and persistent dry periods, respectively. Applying this new interpretation, we find that ENSO events of both phases were generally less frequent during the mid-Holocene (similar to 6100-4000 calendar years B.P.) relative to the last similar to 1500 calendar years. Abundant carbonate laminations between 3500 and 3000 calendar years B.P. imply that conditions in the Galapagos region were cool and dry during this period when the tropical Pacific E-W sea surface temperature (SST) gradient likely strengthened. The frequency of El Nino and La Nina events then intensified dramatically around 1750-2000 calendar years B.P., consistent with a weaker SST gradient and an increased frequency of ENSO events in other regional records. This strong interannual variability persisted until similar to 700 calendar years B.P., when ENSO-related variability at the lake decreased as the SST gradient strengthened. Persistent, dry conditions then dominated between 300 and 50 calendar years B.P. (A.D. 1650-1900, +/- similar to 100 years), whereas wetter conditions and frequent El Nino events dominated in the most recent century. Plain Language Summary Sediments accumulating at the bottom of Bainbridge Crater Lake have provided a record of Galapagos climate and the frequency of El Nino events over the past similar to 6000 years. Motivated by the importance of this lake for our understanding of climate in the tropical Pacific Ocean, we have been monitoring the link between climate, lake conditions, and the physical and chemical properties of the lake sediments since 2009. Based on this long-term monitoring, we find that the Bainbridge sediment record preserves both El Nino and La Nina events. This makes Bainbridge a particularly valuable archive of past climate, as most sediment-based records typically preserve only one or the other key phase of tropical Pacific climate.

Typically, multi-model ensemble studies show mixed responses of El Nino Southern Oscillation (ENSO) under global warming, so it is currently unknown how, or even if, global warming will impact ENSO and its teleconnections. ENSO is governed by various ocean-atmosphere interactions in the equatorial Pacific, which provide either positive amplifying or negative damping feedbacks and are not always accurate in models. This results in uncertainty in projected ENSO responses. In a flux adjusted HadCM3 perturbed physics ensemble, the Bjerknes' stability index (BJ index), a measure of ENSO stability, has been used to analyse the strength of ENSO feedbacks and their response under the SRES A1B warming scenario with respect to mean climate conditions. Despite mean sea surface temperature biases being minimised by flux adjustment, the important dominant feedbacks, namely the latent heat flux feedback, shortwave flux feedback, the thermocline feedback and the zonal advective feedback are found to be too weak in the ensemble. Common model biases cause weak ocean-atmosphere interactions such as a weak response of ocean currents to wind stress anomalies, a weak thermocline slope response to wind stress anomalies and weak thermodynamic dampings. These biases are linked to overly strong zonal surface ocean currents and convective response biases. Under global warming, a large increase in thermodynamic damping, caused by increasing shortwave damping, is found. This increase is linked to a strong convective response and overrides other feedback responses, resulting in a weakening BJ index in contrast to increasing ENSO amplitude. Positive feedback responses are also found but counteract each other, so have relatively little impact on total ENSO stability. Results here show that common model biases, such as the cold tongue bias, are linked to persistent ENSO feedback biases pointing to areas of improvement in future models. Results also suggest that caution must be exercised when using the BJ index to assess ENSO, as the BJ index is not always representative of ENSO amplitude. This may be caused by non-linearities in ENSO feedbacks which are not accounted for by the linear approximations used in the BJ index, or by ENSO feedbacks not being directly comparable in magnitude, as assumed by the BJ index calculation.

The aim of this thesis is to estimate the market value of the company Stora Enso Wood Products Ždírec s.r.o. to the date of 1st April 2015. For this purpose a strategic analysis was firstly conducted. This analysis focused not only on the environment where the company operates, but also on internal factors that significantly affect the company's competitiveness in the specific timber market. Consequently the financial stability and performance of the company was assessed through financial analysis. Its results confirmed the principle of going concern which enabled to estimate the market value of the company using some of the income approach. Due to adjustment of the capital structure, the two-step model of DCF Equity method was chosen. The determined value of the company was finally compared with a book value of equity.

Syftet med arbetet var att upprätta en svavel- och kloridbalans för Skoghalls bruk för att bättre kunna förstå sulfatfabrikens in- och utflöde av anjonerna. Detta gjordes genom att undersöka några av de största och mest intressanta in- och utflöden innehållande svavel och klor. Det var dessutom fokus på att studera analysmetoden för pappersmassorna då vissa balanser som utförts tidigare gett orimliga resultat. Det undersöktes genom att analysera halten av anjonerna som fanns i fibern respektive löst i filtrat.  Upparbetade prover analyserades i en jonkromatograf alternativt med titrering för att erhålla halter av anjonerna. Erhållen balans hade en ökning i både in- och utlopp jämfört med tidigare internt beräknade värden. De tydligaste avvikelserna var halterna i oblekt och blekt massa men även CTMP- avlopp, tvättvätska från blekeriet och restsyra. Differenserna skulle kunna bero på olika metoder för upparbetning av proverna då det inte var givet för referensvärdena.  Resultat visade även att största andelen anjoner sitter lösta i vätskan vilket stämmer med teorin att fibrerna lättare binder katjoner. Att anjoner är mest anrikade i vätskan ger antagandet att även största andelen av de utlösta extraktivämnena som är negativt laddade, borde finnas i vätskan och kan tvättas bort. Slutsatserna för arbetet blev att man i framtida analyser behöver analysera fler provströmmar som täcker en större del av fabrikens in- och utflöden av svavel och klor, samt att utföra fler mätningar av massaprover då metoden ger stor variation av halter.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23479号 / 工博第4891号 / 新制||工||1764(附属図書館) / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 立川 康人, 准教授 市川 温, 教授 角 哲也 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

This project summarizes the findings of research organized in two parts. The first involved the characterization of changes in the variability of climate that lead to extreme events. The second focused on the predictability of extreme climate on time-scales ranging from short forecast lead-times to long-lead climate predictions exceeding a year. Initial studies focused on three interrelated, yet regionally unique extreme climate phenomena. First, the relationship between increasing greenhouse gas (GHG) emissions and particulate matter (PM) concentration in basin terrain was investigated. Next, we evaluated changes in large-scale atmospheric circulation associated with two climate phenomena at either extreme side of the water cycle--droughts and floods. In the final analysis, an attempt was made to understand the mechanisms that link two North Pacific ENSO precursor patterns to the ENSO cycle.

[ES] Las sequías han incrementado significativamente en las últimas décadas, y se espera que el cambio climático contribuya a esta tendencia creciente, lo que plantea mayores riesgos para aquellos sectores que dependen de la precipitación y los recursos hídricos. Por ello es necesario la detección temprana de la sequía para implementar estrategias y medidas de mitigación antes de que ocurra el evento. En esta investigación se caracterizan las sequías de la Demarcación Hidrográfica de Manabí (DHM) para entender el inicio, desarrollo y el fin del evento. Se realiza un análisis de las sequías para identificar el impacto económico que tiene el evento en la demarcación. Se ha desarrollado un sistema de predicción de sequía basado en Oscilación del Sur-El Niño (ENSO) e índices de sequías, y se han establecido medidas de gestión de sequías que permitan a los tomadores de decisiones prepararse al evento. La caracterización de las sequías en la demarcación, parte del análisis de las series históricas de precipitación y temperatura en el período octubre/1964 - septiembre/2012; para obtener la serie histórica de índices de sequía. Los índices aplicados son el Índice de Precipitación Estandarizado (SPI) y el Índice de Severidad de Sequía de Palmer (PDSI). Los resultados de los índices se validaron con los comunicados de prensa históricos disponibles en el Sistema de Inventario de Desastres. Los resultados indican que en la DHM las sequías son estacionales y anuales. En la Zona Norte y Centro el evento es de corta duración, y puede durar entre 3 y 9 meses y con frecuencia son incipientes y leves. En la Zona Sur, las sequías pueden durar más de un año, llegando a ser extremas. Para el desarrollo del sistema de predicción de sequías se correlacionó el Índice de Oscilación del Sur (SOI), el Índice de Niño Oceánico (ONI), la Temperatura de la Superficie del Mar (SST) en las regiones Niño 4.3, 3.4 y 1+2; y los índices de sequía aplicados, SPI y PDSI, para estimar la relación entre los eventos ENSO y la ocurrencia de sequía en la demarcación. El análisis de las correlaciones permite establecer un sistema de detección temprana de sequía basado en anomalías SST región Niño 1+2 (lag -7), SST región Niño 3 (lag -9) y SST región Niño 3.4 (lag -9) y en ambos índices de sequía. El sistema propuesto debe aplicarse en diciembre para detectar la sequía estacional y en mayo para detectar la sequía anual. Las medidas de mitigación de sequías se dividen en estratégicas, tácticas y de emergencia. Para establecer las etapas, los indicadores y los umbrales de la sequía, se toma como referencia los estándares internacionales y los Lineamientos publicados por la Comisión Nacional del Agua - México. / [CA] Les sequeres s'han incrementat significativament en les últimes dècades, i s'espera que el canvi climàtic contribueixi a aquesta tendència creixent, el que planteja més riscos per a aquells sectors que depenen de la precipitació i els recursos hídrics. Per això cal la detecció primerenca de la sequera per implementar estratègies i mesures de mitigació abans que passi l'esdeveniment. En aquesta investigació es caracteritzat les sequeres de la demarcació hidrogràfica de Manabí per entendre l'inici, desenvolupament i la fi de l'esdeveniment. S'ha realitzat una anàlisi de les sequeres per identificar l'impacte econòmic que té l'esdeveniment a la demarcació. Finalment s'ha desenvolupat un sistema de predicció de sequera basat en El Nen Oscil·lació de l'Sud (ENSO) i índexs de sequeres, i han establert mesures de gestió de sequeres que permetin als prenedors de decisions preparar-se a l'esdeveniment. La caracterització de les sequeres a la demarcació, part de l'anàlisi de les sèries històriques de precipitació i temperatura en el període octubre / 1964 - setembre / 2012; per obtenir la sèrie històrica d'índexs de sequera. Els índexs aplicats són l'Índex de Precipitació Estandarditzat (SPI) i l'Índex de Severitat de Sequera de Palmer (PDSI). Els resultats dels índexs es van validar amb els comunicats de premsa històrics disponibles en el Sistema d'Inventari de Desastres. Els resultats indiquen que a la DHM les sequeres són estacionals i anuals. A la Zona Nord i Centre l'esdeveniment és de curta durada, i pot durar entre 3 i 9 mesos i amb freqüència són incipients i lleus. A la Zona Sud, les sequeres poden durar més d'un any, arribant a ser extremes. Per al desenvolupament de sistema de predicció de sequeres es va correlacionar l'Índex de Oscil·lació de l'Sud (SOI), l'Índex de Nen Oceànic (ONI), la Temperatura de la Superfície de la Mar (SST) en les regions Nen 4.3, 3.4 i 1+2; i els índexs de sequera aplicats, SPI i PDSI, per estimar la relació entre els esdeveniments ENSO i l'ocurrència de sequera a la demarcació. L'anàlisi de les correlacions permet establir un sistema de detecció primerenca de sequera basat en anomalies SST regió Nen 1+2 (lag -7), SST regió Nen 3 (lag -9) i SST regió Nen 3.4 (lag -9) i en tots dos índexs de sequera. El sistema proposat s'ha d'aplicar al desembre per detectar la sequera estacional i al maig per detectar la sequera anual. Les mesures de mitigació de sequeres es divideixen en estratègiques, tàctiques i d'emergència. Per establir les etapes, els indicadors i els llindars de la sequera, es pren com a referència els específics internacionals i els Directrius publicats per la Comissió Nacional de l'Aigua - Mèxic. / [EN] Droughts have increased significantly in recent decades, and climate change is expected to contribute to this growing trend, which poses greater risks for those sectors that depend on precipitation and water resources. Therefore, early detection of drought is necessary to implement mitigation strategies and measures before the event occurs. In this research the droughts of Manabí River Basin District (MRBD) are characterized to understand the beginning, development and end of the event. An analysis of droughts is carried out to identify the economic impact that the event has on the River Basin District. A drought prediction system based on El Niño Southern Oscillation (ENSO) and drought indices has been developed, and drought management measures have been established that allow decision makers to prepare for the event. The characterization of droughts in the River Basin District, start of the analysis of the historical series of precipitation and temperature in the period October/1964 - September/2012 to obtain the historical series of drought indices. The indices applied are the Standardized Precipitation Index (SPI) and the Palmer Drought Severity Index (PDSI). Index results were validated with the historical press releases available in the Disaster Inventory System. The results indicate that in the DHM the droughts are seasonal and annual. In the North and Central Zone the event is of short duration, and can last between 3 and 9 months and are often incipient and mild. In the South Zone, droughts can last more than a year, becoming extreme. For the development of the drought prediction system, the Southern Oscillation Index (SOI), the Ocean Niño Index (ONI), the Sea Surface Temperature (SST) in the Niño 4.3, 3.4 and 1+2 regions; and the applied drought indices, SPI and PDSI, were correlated to estimate the relationship between ENSO events and the occurrence of drought in the River Basin District. The correlation analysis allows establishing an early drought detection system based on anomalies SST Niño 1+2 region (lag -7), SST Niño 3 region (lag -9) and SST Niño 3.4 region (lag -9) and in both drought indices. The proposed system should be applied in December to detect seasonal drought and in May to detect annual drought. Drought mitigation measures are divided into strategic, tactical and emergency. In order to establish the stages, the indicators and the thresholds of the drought, the international specific ones and the Guidelines published by the National Water Commission - Mexico are taken as reference. / A la Secretaría de Educación Superior, Ciencia, Tecnología e Innovación del Ecuador (SENESCYT) por financiar esta investigación en el programa de becas: "Convocatoria Abierta 2012, Segunda Fase" (contrato 323 -2012). / Zambrano Mera, YE. (2020). Determinación de medidas de gestión de sequías en climas tropicales. Aplicación a la Demarcación Hidrográfica de Manabí - Ecuador [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/149400 / TESIS

No description available.

El Niño Southern Oscillation events have global implications both climatologically and socio-economically. One such climatological teleconnection is manifested in the Amundsen Sea region (ASR). The Amundsen sea low (ASL) is the dominant low pressure system located around the ASR and is important to the climate of Western Antarctica. Therefore, it is important to understand the ASL and any phenomena that may affect it. This thesis focuses on the ENSO--ASR teleconnection under El Niño conditions and the mechanism behind it. The ENSO--ASR teleconnection was explored using the UM version 8.4 (HadGEM3) model. Time--slice experiments with various magnitudes of idealised perpetual ENSO events are imposed. Two sets of `switch on' experiments in which tropical Pacific SSTs were ramped up were also carried out to investigate the transient nature of the teleconnection. The seasonality of the ENSO--ASR teleconnection is known from previous studies to be stronger in winter compared to summer. The mechanism behind the seasonality was explored using the time--slice experiments. The seasonality is found to originate from the seasonal differences in the Southern Hemispheric jets. As the subtropical jet is only present in austral winter, Rossby wave source anomalies can only be generated in the mid--latitudes in winter. Furthermore, the propagation of the Rossby waves is not possible in summer due to the strong polar front jet. The lack of the source and propagation in summer explains the weaker ENSO--ASR teleconnection. A flowchart summarising the mechanism was created and then verified by the transient runs. The linearity of the ENSO--ASR teleconnection within El Niño has not been previously investigated. This is mainly due to insufficient reanalysis data available to overcome the high internal variability in the ASR. In this thesis, the linearity of the teleconnection under El Niño is studied using the time--slice runs. The results indicate linearity (within errorbars) for both the summer and winter seasons up to historically maximum El Niños. However, under extreme El Niños (beyond historic records) in winter, the teleconnection is no longer linear. The UPSCALE dataset was used to investigate the effects of horizontal resolution on the simulation of the ASL climatological state and the ENSO--ASR teleconnection. The UPSCALE dataset consists of ensembles of HadGEM3 simulations at three different horizontal resolutions. The high resolution model was found to better simulate the ASL while the low resolution model was found to better simulate the ENSO--ASR teleconnection.