Publicación a texto completo no autorizada por el autor / Evalúa e interpreta la predicción de las Anomalías de la Temperatura Superficial del Mar (ATSM) frente a la costa de Sudamérica asociada al fenómeno El Niño-Oscilación del Sur (ENOS), se analizaron los resultados de las dos interpretaciones del modelo climático acoplado (océano - tierra - atmósfera) CLIMATE FORECAST SYSTEM (CFS) del organismo National Centers for Enviromental Prediction (NCEP) de la National Oceanic and Atmospheric Administration (NOAA) de los EEUU. La primera versión del modelo hace el pronóstico hasta 9 leads (meses) a futuro y se toma para el estudio los pronósticos para el periodo de los años 1982-2009 para la región Niño 1+2; la segunda versión del modelo hace el pronóstico hasta 10 leads (meses) a futuro y se toma el periodo 1983-2010 para la misma región. Los mayores coeficientes de correlación entre los pronósticos del CFSv1 (versión 1) y los datos observados se dieron entre los meses mayo-diciembre con un valor entre 0.65 y 0.9. Estos valores son mayores hacia los últimos meses del año y disminuyen a manera que se incrementan el tiempo de pronósticos; los mayores coeficientes de correlación para el CFSv2 (versión2) se observa entre los meses abril-mayo y octubre-enero; como un primer resultado se observa que los coeficientes de correlación de CFSv2 son menores que los coeficientes que CFSv1. Se realiza también el mismo procedimiento y análisis de los pronósticos de anomalías de TSM para las regiones Niño 3, Niño 3.4 y Niño4; de la misma manera para el estudio en tres periodos del CFSv1 abarcando los siguientes años 1982-1990, 1991-2000, 2001-2009, y para el CFSv2 los años 1983-1990, 1991-2000, 2001-2010. Las correlaciones fueron buenas para los primeros dos periodos, pero en el último periodo se observaron bajos niveles de correlación para la región Niño 1+2 en las 2 predicciones del CFS, donde los niveles de correlación incluso fueron en algunos meses negativos. Se sugiere que esto último se debe a cambios decadales en el clima del Pacífico que ha llevado en una predominancia de eventos “El Niño Modoki”. El CFS también hace pronósticos de otras variables y/o indicadores, entre ellos se utilizo el Contenido de Calor en el Océano (CCO), Profundidad de la Isoterma de 15 ◦C (PI15◦C) y Nivel Medio del Mar (NMM) como posibles predictores de cambios en el océano Pacífico, los resultados de estas variables indicaron que no son mejores que la TSM modelada por el mismo modelo. La importancia de este trabajo es la utilidad para un eventual pronóstico de un evento Niño en el OP, en especial el monitoreo de la región Niño 1+2. / Tesis

The connection between Upper Tropospheric Cyclonic Vortex (UTCV) and Brazilian Northeast Jet Stream (BNEJS) was analyzed for 9 years between 1988 and 2000, separated by El Niño, La Niña and Neutral years. Through the reanalysis products from NCEP, and METEOSAT satellite images in the infrared channel, were observed 167 UTCVs, most of them originated over the Atlantic Ocean with an average last of 4 days and showed no significant variability in years of El Niño and La Niña. Approximately 54% of the observed UTCVs were associated to air currents superior than 20m.s-1 in its periphery, these currents are called BNEJS. In El Niño years was observed an increase of BNEJS cases associated to UTCV, while in La Niña years, the number of occurrences was practically the same as in neutral years. The BNEJS showed intensitity up to 40 m.s-1, and the most observed wind directions were from south, southeast, northwest and west. Thus, 3 patterns of occurrence of BNEJS were identified, named Meridional, Zonal and Transversal. The Meridional BNEJS occurs in the UTCVs west periphery, usually over the continent, showing the upward movements between the BNEJS and the Northern Subtropical Jet Stream (NSJS). And finally, the transversal BNEJS, showed two kinds of currents, one from southeast and another from northwest. In these cases, the UTCVs axis showed an inclination to west and the upward movements were observed in the UTCVs periphery, where the winds were weaker. Thus, three cases were chosen to represent the observed patterns and investigate the vertical movements, comparing to the cloudiness in the satellite images, where was observed, in both cases, that the upward movements doesn t exists or are too weak in the jet streak BNEJS area. / Conselho Nacional de Desenvolvimento Científico e Tecnológico / A ligação entre Vórtice Ciclônico em Altos Níveis (VCAN) e a Corrente de Jato do Nordeste Brasileiro (CJNEB), foi analisada durante 9 anos entre 1988-2000, divididos em períodos de El Niño, La Niña e Neutro. Através dos produtos de reanálise do NCEP, e imagens do satélite METEOSAT no canal infravermelho, foram observados 167 VCAN s, em grande maioria originados sobre o oceano Atlântico, com uma duração média de 4 dias, não apresentando variabilidade significativa em anos de El Niño e La Niña. Dos VCAN s observados, aproximadamente 54%, estavam associados a correntes de ar superiores a 20m.s-1 em sua periferia, essas correntes são chamadas de CJNEB. Em anos de El Niño, foi observado um aumento dos casos de CJNEB associados à VCAN, enquanto que em anos de La Niña, o número de ocorrências foi praticamente o mesmo que em anos neutros. As CJNEB apresentaram intensidade de até 40 m.s-1, e as direções mais observadas foram de sul, sudeste, noroeste e oeste. Assim, foram identificados 3 padrões de ocorrência de CJNEB, denominadas de Meridional, Zonal e Transversal. A CJNEB Meridional ocorre na periferia oeste do VCAN, geralmente sobre o continente, apresentando os movimentos ascendentes no lado oeste da corrente. A CJNEB Zonal ocorreu sobre a periferia norte do VCAN, apresentando movimentos ascendentes entre a CJNEB e o Jato Subtropical do Hemisfério Norte (JSTHN). E finalmente, a CJNEB Transversal, que apresentou dois tipos de correntes, uma de sudeste e outra de noroeste. Nesses casos, o eixo do VCAN apresentou uma inclinação para oeste, e os movimentos ascendentes foram observados na periferia do VCAN, onde os ventos foram mais fracos. Assim, três casos foram escolhidos a fim de representar os padrões observados e investigar os movimentos verticais, comparando com a nebulosidade nas imagens de satélites, onde foi observado em ambos os casos, que os movimentos ascendentes inexistem ou são muito fracos na região mais intensa da CJNEB ( Jet Streak ).

Made available in DSpace on 2016-06-02T19:28:52Z (GMT). No. of bitstreams: 1 TeseJELB.pdf: 1718672 bytes, checksum: 2d711e25884ea18ec2a00592f22b4906 (MD5) Previous issue date: 2002-03-01 / Financiadora de Estudos e Projetos / In the semi-arid North-east region of Brazil occurs the second highest density of dams in the world (or açudes , as they are locally known) which supply water to ca. 40 millions inhabitants, mainly during the dry period, a catastrophic and frequent event in that Brazilian region. The limnological functioning of such water system in the Taperoá II dam (07o11 44 S and 07o13 44 S, 36o52 03 W and 36o50 09 W) was investigated through sampling carried out between September/1998 and September/2000. Sampling was performed at four collecting stations: three of them at the pond margins and one in its pelagic zone, where four depths were selected: surface, 50% and 1% light penetration, and at 4.0m depth. Climatological characteristics of the region (air temperature, evaporation, winds, and rainfall) were analysed, as well as the physical and chemical properties of the water (temperature, dissolved oxygen, pH, electric conductivity, alkalinity, turbidity, transparency, total dissolved inorganic carbon, ammonia, nitrite, nitrate, total phosphorus, orthophosphate, and silicate). Climatic variations due to El Niño event (1997-1998) caused, between September/98 and January/99, a drastic reduction of the available stock of water in the pond, which determined a strong concentration of dissolved salts, an alkaline pH, high electric conductivity and high inorganic nutrient contents. The diluter effect of the increased rainfall in February and March/1999 exerted a reduction of oxygen, conductivity, and dissolved nutrients and caused water acidity. The recovery of the pond hydrometric volume and its stability, maintained the limnological variables almost unchanged up to the next rainy period. A relative thermal stratification occurred between February and April/2000 simultaneously to a chemical stratification. The Principal Components analysis allowed to distinguish the system based on the highest limnological variables here studied and the water volume fluctuation, showing that the interaction of extreme dry season and rainfall in a short period, are the strongest determinants of the high interannual variability of the sampled variables and of the reduced spatial oscillations of the horizontal and vertical axes of the dam. / A região semi-árida do Nordeste do Brasil conta com a segunda maior densidade de açudes do mundo, responsável pelo abastecimento de 40 milhões de pessoas, principalmente, nos períodos de seca, evento climático freqüente e conseqüentemente catastrófico nesta parte do Brasil. Com o objetivo de analisar o funcionamento limnológico destes sistemas aquáticos foram realizadas no açude Taperoá II (07°11 44 S e 07°13 44 S, 36°52 03 W e 36°50 09 W), amostragens mensais durante o período de setembro de 1998 e setembro de 2000. Estas foram realizadas em quatro estações de coletas: três localizadas na região marginal e uma na região pelágica do açude, sendo nesta em quatro profundidades (superfície, 50%, 1% de penetração de luz e a 4,0 m de profundidade). Foram analisadas as características climatológicas da região (temperatura do ar, evaporação, ventos, precipitação pluviométrica) e aspectos físicos e químicos da água (temperatura, oxigênio dissolvido, pH, condutividade elétrica, alcalinidade, turbidez, transparência da água, carbono inorgânico dissolvido total, amônia, nitrito, nitrato, fósforo total, ortofosfato e sílica). As alterações climáticas decorrentes do fenômeno El Niño 1997-1998 provocaram entre setembro/98 e janeiro/99 redução drástica do volume útil de armazenamento do açude, acarretando forte concentração de sais dissolvido, pH alcalino, elevada condutividade elétrica e altos teores de nutrientes inorgânicos. O efeito diluidor das chuvas concentradas nos meses de fevereiro e março de 1999, provocou redução do oxigênio, acidez do meio, redução acentuada nos valores de condutividade e nutrientes dissolvidos. A recuperação do volume hidrométrico do açude e sua estabilidade manteve as variáveis limnológicas pouco alterados até o período chuvoso seguinte. A relativa estratificação térmica ocorrida entre os meses de fevereiro e abril de 2000 foi acompanhada por estratificação química. A análise de Componentes Principais discriminou o sistema com base nos maiores valores registrados para as variáveis limnológicas estuda e a flutuação do volume do açude, indicando que a interação seca extrema e chuvas concentradas em curto período, são os maiores determinantes da alta variabilidade interanual das variáveis amostradas e as reduzidas oscilações espaciais dos eixos horizontal e vertical do açude.

This article presents evidence of a mega Niño event that transpired around ca. 600 d.C. recovered at the archaeological site of Huaca 20-Complejo Maranga and discusses the human eco-dynamics that could have happened at the end of the Early Intermediate Period in this site and other settlements of the Lima Valleys. is information is compared with contemporary data from the North Coast. I propose that this period of environmental stress could have signied a time of opportunities for some societies of the Early Intermediate Period. / Este artículo presenta evidencia de un mega El Niño ocurrido alrededor de ca. 600 d.C. registrada en el sitio arqueológico Huaca 20-Complejo Maranga. Se discute las dinámicas hombre-medio ambiente (ecodinámicas humanas), que pudieron haber sucedido a nes del Periodo Intermedio Temprano en este sitio y en otros asentamientos de los valles de Lima. Se compara también estos datos con información contemporánea procedente de la Costa Norte y se propone queeste periodo de stress ambiental pudo haber signicado un momento de oportunidad para las sociedades del Periodo Intermedio Temprano.

Este estudo discute uma climatologia de 59 anos (1949-2007) de bloqueios no Hemisfério Sul (SH) usando dados de altura geopotencial em 500-hPa das reanálises do National Center for Environmental Prediction / National Center for Atmospheric Research (NCEP-NCAR). A variabilidade espaço-temporal dos eventos de bloqueio e associações com o El Niño/Oscilação do Sul (ENOS) também foram examinadas. Adicionalmente, os bloqueios foram investigados em dois Modelos de Circulação Geral Acoplados Atmosfera-Oceano de clima (MCGAO) do Intergovernamental Painel for Climate Change (IPCC), o ECHAM5/MPI-OM e o MIROC 3.2. Dois cenários simulados foram analisados: O clima do século XX e o cenário de emissão A1B. Os episódios do ENOS foram identificados usando dois métodos. O primeiro foi o Índice Oceânico Mensal do Niño (ONI) do Climate Prediction Center (CPC-NCEP). O segundo método foi baseado em Funções Empíricas Ortogonais (EOF) e foi aplicado nos MCGAOs. Similarmente, também foi examinado a influencia combinada do ENOS e a Oscilação Antártica (AAO) na ocorrência e características dos bloqueios. O índice diário da AAO foi obtido pelo CPC-NCEP. Os índices convencionais de bloqueios detectam principalmente variações longitudinais. Este trabalho propõe um índice de bloqueio que detecta, além de variações longitudinais também as variações latitudinais dos bloqueios. Cinco setores relevantes de bloqueios foram examinados em detalhes: Indico Sudoeste (SB1), Pacífico Sudoeste (SB2), Pacífico Central (SB3), Pacífico Sudeste (SB4) e Atlântico Sudoeste (SB5). Além disso, foram investigados duas grandes regiões do Pacífico Sul: Pacífico Oeste e Pacífico Leste. Foi encontrado que a escala média típica dos eventos de bloqueio varia entre 1,5 e 2,5 dias. Além disso, a duração dos eventos depende da latitude, com eventos de maior duração observados em latitudes mais altas. Diferenças longitudinais estatisticamente significativas na freqüência do escoamento bloqueado foram observadas entre as fases Quente e Neutra do ENOS desde o outono a primavera. Episódios intensos da fase Quente do ENOS (isto é, moderados a fortes) tendem a modificar o local preferencial de bloqueio, mas não a freqüência. Por outro lado, os episódios fracos da fase Quente do ENOS estiveram associados relativamente com alta freqüência. Os Eventos de bloqueio durante o ENOS+ duram, em média, mais um dia relativamente aos episódios Neutros. Em contraste, a fase Fria do ENOS (ENOS-) caracterizou-se pela redução dos eventos de bloqueio sobre o setor do Pacífico Central, exceto durante os meses do verão austral. Entretanto, nenhuma diferença estatisticamente significativa foi detectada na duração dos eventos. Composições de anomalias de vento em 200-hPa indicam que o enfraquecimento (fortalecimento) do jato polar em torno de 60ºS durante a AAO negativa (positiva) em ambas as fases do ENOS tem uma importância significativa no aumento (redução) dos eventos de bloqueio. Um significativo aumento estatístico dos eventos sobre o setor do Pacífico Sudeste foi observado durante a AAO negativa em ambas as fases do ENOS. Ainda, um aumento (redução) dos eventos foi observado sobre a região do Pacífico Oeste na fase negativa (positiva) da AAO durante o ENOS-. Em contraste, durante o ENOS+ não houve diferenças estatisticamente significativas na distribuição longitudinal dos eventos separado de acordo com as fases opostas da AAO, embora haja um aumento (redução) dos eventos da região do Pacífico Oeste para o Pacífico Leste durante a fase negativa (positiva) da AAO. Os MCGAOs simularam corretamente a amplitude do ciclo anual observado. Também, ambos os MCGAOs simularam melhor a duração e o local preferencial do que freqüência. Nenhum MCGAO simulou adequadamente a freqüência durante a fase Neutra do ENOS. O ECHAM5/MPI-OM (rodada 2) mostra um erro sistemático que levam a uma superestimativa na freqüência de eventos sobre o Pacífico Leste durante as fases Neutra e Fria do ENOS. As diferenças entre as duas versões do MIROC 3.2 indicam que a alta resolução nos modelos melhora o desempenho em simular a freqüência de bloqueios. / This study discusses 59-yr climatology (1949-2007) of Southern Hemisphere (SH) blockings using daily 500-hPa geopotential height data from National Center for Environmental Prediction / National Center for Atmospheric Research (NCEP-NCAR reanalysis. The spatiotemporal variability of blocking events and associations with El Nino/Southern Oscillation (ENSO) are examined. Additionally, blockings were examined in two Intergovernmental Panel for Climate Change (IPCC) Coupled General Circulation Models (CGCM), ECHAM5/MPI-OM and MIROC 3.2. Two sets of simulations were examined: the climate of the 20th century and the A1B emission scenario. ENSO episodes were identified using two methods. The first method was the Monthly Oceanic Niño Index (ONI) from the Climate Prediction Center (CPC-NCEP). The second method was based on Empirical Orthogonal Function (EOF) and was applied to identify ENSO episodes in the CGCMs. Similarly, the combined influence of ENSO and the Antarctic Oscillation (AAO) on the occurrence and characteristics of blockings was also examined. The daily AAO index was obtained from CPC/NCEP. Most conventional blocking indices detect longitudinal variations of blockings. In this study we propose a new blocking index that detects longitudinal and latitudinal variations of blockings. The following relevant sectors of blocking occurrence were identified and examined in detail: Southeast Indian (SB1), Southwest Pacific (SB2), Central Pacific (SB3), Southeast Pacific (SB4) and Southwest Atlantic (SB5) oceans. In addition, we investigated two large regions of South Pacific: West Pacific and East Pacific. We found that the typical timescale of a blocking event is about ~1.5 2.5 days. Nonetheless, the duration of events depends on the latitude, with larger durations observed at higher latitudes. Statistically significant differences in the longitude of blockings are observed between Warm (ENSO+) and Neutral ENSO phases from the Austral fall to spring. Moderate to strong Warm ENSO episodes modulate the preferred locations of blockings but do not play a significant role for variations in their frequency. On the other hand, weak ENOS+ episodes were associated with relatively high frequency of blockings. Blocking events during ENSO+ last on average one more day compared to events that occur during Neutral episodes. In contrast, Cold (ENOS-) ENSO episodes are characterized by a decrease of blockings over the Central Pacific sector, except during the Austral summer months. However, no statistically significant differences are detected in the duration. Composites of 200-hPa zonal wind anomalies indicate that the weakening (strengthening) of the polar jet around 60oS during negative (positive) AAO phases in both ENSO phases plays a major role for the relative increase (decrease) of blocking events. A statistically significant increase of events over Southeast Pacific is observed during negative AAO phases in both ENSO phases. Moreover, an increase (decrease) of events is observed over West Pacific region when negative (positive) AAO phases occur during ENSO-. In contrast, during ENSO+ there is no statistically significant difference in the longitudinal distribution of events separated according to opposite AAO phases, although there is an increase (decrease) in the events from West Pacific region to East Pacific during negative (positive) AAO phase. The CGCMs investigated in this study correctly simulated the amplitude of observed annual cycle of geopotential height in the extratropics. Also, both CGCMs show a better performance in simulating the duration and preferred locations of blockings than their frequency. None of these CGCMs simulated well the frequency during Neutral ENSO phase. The ECHAM5/MPI-OM (run2) shows systematic biases in some regions. For instance, this model overestimates the frequency of blockings over East Pacific region during Cold and Neutral ENSO phases. The differences between the two versions of MIROC 3.2 indicate that the increase in resolution improves the performance of the model in simulating the frequency of blockings.

Coral mortality caused by El Niño–Southern Oscillation (ENSO) activity and its related disturbances has been researched throughout the Eastern Pacific. In the past three decades, disturbances related to the El Niño–Southern Oscillation (ENSO) have been shown to influence coral growth in the Eastern Pacific. In the Galápagos Islands, Ecuador, more than 97% of corals experienced mortality after the severe 1982-1983 ENSO episode. However, two of the most dominant coral species found in a coral community adjacent to Devil’s Crown; Psammocora stellata and Diaseris distorta survived this severe ENSO event. By reconstructing sediment cores of the coral community, this study assessed how the coral assemblage has changed over the past 7,700 years of the Holocene epoch. The historical reconstructions were then related to existing records of Holocene ENSO variability in order to determine if changes in the relative abundance of coral species were related to ENSO activity and disturbances. We observed high variability in the relative abundances of P. stellata and D. distorta in the cores, including an increase in the abundance of D. distorta at approximately 2,200 yBP. Between the two species, opposite abundance trends were observed and supported by Detrended Correspondence Analysis (DCA) and Non-metric Multidimensional Scaling (NMDS) ordination analysis. Overall, the high variance in coral composition at the site throughout the Holocene documents repeated disturbance events in this region.

A variety of anthropomorphic and environmental stresses are threatening the existence of all seven species of sea turtles. There is growing evidence that alterations in surface waters and sediment temperatures are negatively impacting reproductive success of loggerhead sea turtles (Caretta caretta). Fluctuations in water temperature associated with localized climate oscillations heavily alter the food web dynamics of the ocean. Feeding conditions are expected to be a critical factor in determining body mass and productivity for breeding seasons. An increase in regional temperatures could lead to prolonged reduction in food sources, as well as reduced nesting and recruitment. Loggerhead sea turtle nesting data from 1995-2011 werre compared with the average yearly North Atlantic Oscillation (NAO) and Atlantic Multidecadal Oscillation (AMO) which are important climatic events impacting the SST in the Atlantic Ocean. Because El Niño Southern Oscillation (ENSO) is a global event, it was proposed that turtles in the Atlantic may follow a similar trend. ENSO was quantified using Oceanic Nino Index (ONI). Analysis of loggerhead sea turtle nest frequencies from the years 1995-2011 in comparison to seasonal climate changes showed a significant inverse relationship between the detrended loggerhead nests and average yearly NAO when lagged two years, suggesting loggerheads may spend years prior breeding obtaining optimum body mass to increase successful reproduction. The detrended nesting data showed a tendency toward higher occurrence of nests during La Niña years while nest frequencies decreased during El Niño year; when the yearly detrended loggerhead nesting data was compared with the average yearly ONI; showing a significant inverse relationship without a lag. This may also suggest a relationship between changes of productivity of the ocean influenced by smaller scale climate changes and loggerhead nest frequencies.

Uncertainty in rainfall forecasts affects the level of quality and assurance for decisions made to manage water resource-based systems. However, eliminating uncertainty in a complete manner could be difficult, decision-makers thus are challenged to make decisions in the light of uncertainty. This study provides statistical models as an approach to cope with uncertainty, including: a) a statistical method relying on a Gaussian mixture (GM) model to assist in better characterize uncertainty in climate model projections and evaluate their performance in matching observations; b) a stochastic model that incorporates the El Niño–Southern Oscillation (ENSO) cycle to narrow uncertainty in seasonal rainfall forecasts; and c) a statistical approach to determine to what extent drought events forecasted using ENSO information could be utilized in the water resources decision-making process. This study also investigates the relationship between calibration and lead time on the ability to narrow the interannual uncertainty of forecasts and the associated usefulness for decision making. These objectives are demonstrated for the northwest region of Costa Rica as a case study of a developing country in Central America. This region of Costa Rica is under an increasing risk of future water shortages due to climate change, increased demand, and high variability in the bimodal cycle of seasonal rainfall. First, the GM model is shown to be a suitable approach to compare and characterize long-term projections of climate models. The GM representation of seasonal cycles is then employed to construct detailed comparison tests for climate models with respect to observed rainfall data. Three verification metrics demonstrate that an acceptable degree of predictability can be obtained by incorporating ENSO information in reducing error and interannual variability in the forecast of seasonal rainfall. The predictability of multicategory rainfall forecasts in the late portion of the wet season surpasses that in the early portion of the wet season. Later, the value of drought forecast information for coping with uncertainty in making decisions on water management is determined by quantifying the reduction in expected losses relative to a perfect forecast. Both the discrimination ability and the relative economic value of drought-event forecasts are improved by the proposed forecast method, especially after calibration. Positive relative economic value is found only for a range of scenarios of the cost-loss ratio, which indicates that the proposed forecast could be used for specific cases. Otherwise, taking actions (no-actions) is preferred as the cost-loss ratio approaches zero (one). Overall, the approach of incorporating ENSO information into seasonal rainfall forecasts would provide useful value to the decision-making process - in particular at lead times of one year ahead.

A study of the Nova Scotia surface air temperature over the last century (1900 to 2015) shows that internal variability on inter-annual, decadal and multi-decadal time scales can be partly explained by ocean-atmospheric climate modes, external and anthropogenic forcings. The Atlantic Multidecadal Oscillation (AMO) and Arctic Oscillation (AO) are shown to be the dominant climate drivers in Nova Scotia. The El Niño Southern Oscillation (ENSO) is also shown to be a dominant climate driver but only during the summer. Multivariate models were generated over the full time period using only natural ocean-atmospheric modes of variability but could not explain the rapid increase in the recent rate of warming (post-1980). The inclusion of anthropogenic greenhouse gas forcing to the models improved their predictive power annually and seasonally. The modelling results show that 11% of the annual variability in Nova Scotia results from natural forcings along with anthropogenic greenhouse gas forcing while seasonally up to 28% of the temperature variability can be explained by natural plus greenhouse gas forcings. The annual and seasonal low explained variance suggests that Nova Scotia is poorly modulated by climate indices, specifically during the winter, the time when relationships between ocean-atmospheric modes and the regional climate should be the strongest. It leads to believe that Nova Scotia is located in a transition zone where large-scale ocean-atmospheric modes of variability are transitioning from being positively correlated in a region to being negatively correlated in another region. The results of this study help to better understand how large-scale ocean-atmospheric modes of variability, external and anthropogenic greenhouse gas forcings affect Nova Scotia’s surface air temperatures and also provide insight into future potential variability under a changing climate.

Introduction: Dengue is an endemic disease in Peru and is considered a public health problem. During and after the “El Niño Costero” phenomenon in 2017, the Department of Ica presented 4384 cases of dengue, the highest number of cases in this region. Methods: A cross-sectional analytical study was conducted and included all the families in the district of Palpa, Ica. The main exposure was the report of a previous dengue infection of any family member and we want to find an association with the level of knowledge, attitudes and practices about dengue. Results: We found that the participants who had been exposed to dengue had a 63% higher probability (PR: 1.63; 95% CI: 1.02 - 2.58) of having a high level of knowledge about dengue in comparison with the participants of families who did not have a history of dengue. For the levels of attitudes (PR: 0.90; IC 95%: 0.60 – 1.35) and practices (PR: 0.88; IC 95%: 0.51 – 1.51) no statistically significant differences were found. Conclusions: Our study found that previous exposure to dengue is associated with a high level of knowledge but, it is not associated with a high level of attitude or practices in families in the district of Palpa-Ica. / Introducción: El dengue es una enfermedad endémica en el Perú y es considerada un problema de salud pública. Durante y después del fenómeno del niño costero en el 2017, el Departamento de Ica presentó 4384 casos de dengue, el más alto número de casos en esta región. Métodos: Se realizó un estudio analítico de tipo transversal que incluyó a familias del distrito de Palpa, Ica. La exposición principal fue tener antecedentes de infección por dengue en algún miembro de la familia y se buscó su asociación con el nivel de conocimientos, actitudes y prácticas sobre dengue que tenía el entrevistado. Resultados: Se encontró que los participantes que sí han tenido antecedente de dengue tienen un 63% más de probabilidad (RP: 1.63; IC 95%: 1.02 – 2.58) de tener alto nivel de conocimientos sobre dengue en comparación con los participantes de familias que no tuvieron antecedente de dengue. Para el nivel de actitudes (RP: 0.90; IC 95%: 0.60 – 1.35) y prácticas (RP: 0.88; IC 95%: 0.51 – 1.51) no se encontró diferencias estadísticamente significativas. Conclusiones: Nuestro estudio encontró que el antecedente de dengue de algún miembro de su familia se asocia a un alto nivel de conocimientos; sin embargo, no se asocia a un alto nivel de actitudes o prácticas en las familias del distrito de Palpa, en la región de Ica. / Tesis