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A mediados del 2018 un grupo de investigadores e investigadoras del Centro de Investigaciones Geofísicas y de la Escuela de Física de la Universidad de Costa Rica iniciaron un proyecto para compartir conocimientos sobre las ciencias del tiempo y el clima con la comunidad cabécar de Pú Ksogë (9.591°N, 82.978°W, 114.4 m s. n. m.), Talamanca, Limón. La iniciativa fue apoyada por líderes y autoridades educativas de esa comunidad indígena a finales de ese año. Con el aporte laboral local y la autorización respectiva, se instaló y dejó en operación una estación meteorológica automática (Siwá Etka) en terrenos de la escuela comunal a principios de 2019. Se describen aquí detalles de este proyecto y se muestran los primeros datos atmosféricos observados en la historia de esa comunidad.La falta de un adecuado control comunal y el desinterés de las autoridades de la escuela en el cuido del instrumental provocaron problemas que no permitieron darle continuidad al proyecto y la estación tuvo que ser desinstalada en octubre de 2019. La experiencia tuvo resultados positivos, pero otros aspectos como la conectividad a celular e internet, en ocasiones de muy baja calidad o inexistente, también incidieron en la decisión de descontinuar la iniciativa. Los contactos realizados con una asociación de desarrollo integral de la región podrían ser una alternativa para darle continuidad al proyecto.

Understanding ecohydrological dynamics that result from land-use conversions is fundamental in managing ecosystem services. One common forest transformation in the tropics is the establishment of monospecific plantations with exotic species for timber exploitation, replacing highly diverse natural forests. The impacts of establishing forest plantations in hydrological processes and biogeochemical dynamics, have been highly controversial, with functions from structurally homogeneous plantations being sometimes assumed to be comparable to natural forests. To assess the effects of planting exotic conifer species versus natural forests on hydrological and biogeochemical functions, we measured incoming precipitation, throughfall and stemflow. To compare between forest types, we propose the use of basal area for standardization of hydrochemical fluxes. While net precipitation was similar among forest types, the transmission of water to the forest floor per basal area unit was significantly higher in native forests. Yet, nutrient concentrations were similar among them. However, greater nutrient enrichment per unit basal area was observed for the native species. This more efficient nutrient cycling could be related to native forests being better adapted to oligotrophic soils. The re-establishment of native species rather than with exotic species can result in more efficient hydrochemical regulation, improving the capacity of these ecosystems to produce services.

We introduce Dynamic Constrained Grid (DCGrid), a hierarchical and adaptive grid structure for fluid simulation combined with a scheme for effectively managing the grid adaptations. DCGrid is designed to be implemented on the GPU and used in high-performance simulations. Specifically, it allows us to efficiently vary and adjust the grid resolution across the spatial domain and to rapidly evaluate local stencils and individual cells in a GPU implementation. A special feature of DCGrid is that the control of the grid adaption is modeled as an optimization under a constraint on the maximum available memory, which addresses the memory limitations in GPU-based simulation. To further advance the use of DCGrid in high-performance simulations, we complement DCGrid with an efficient scheme for approximating collisions between fluids and static solids on cells with different resolutions. We demonstrate the effectiveness of DCGrid for smoke flows and complex cloud simulations in which terrain-atmosphere interaction requires working with cells of varying resolution and rapidly changing conditions. Finally, we compare the performance of DCGrid to that of alternative adaptive grid structures.

Due to the complex interplay of various meteorological phenomena, simulating weather is a challenging and open research problem. In this contribution, we propose a novel physics-based model that enables simulating weather at interactive rates. By considering atmosphere and pedosphere we can define the hydrologic cycle - and consequently weather - in unprecedented detail. Specifically, our model captures different warm and cold clouds, such as mammatus, hole-punch, multi-layer, and cumulonimbus clouds as well as their dynamic transitions. We also model different precipitation types, such as rain, snow, and graupel by introducing a comprehensive microphysics scheme. The Wegener-Bergeron-Findeisen process is incorporated into our Kessler-type microphysics formulation covering ice crystal growth occurring in mixed-phase clouds. Moreover, we model the water run-off from the ground surface, the infiltration into the soil, and its subsequent evaporation back to the atmosphere. We account for daily temperature changes, as well as heat transfer between pedosphere and atmosphere leading to a complex feedback loop. Our framework enables us to interactively explore various complex weather phenomena. Our results are assessed visually and validated by simulating weatherscapes for various setups covering different precipitation events and environments, by showcasing the hydrologic cycle, and by reproducing common effects such as Foehn winds. We also provide quantitative evaluations creating high-precipitation cumulonimbus clouds by prescribing atmospheric conditions based on infrared satellite observations. With our model we can generate dynamic 3D scenes of weatherscapes with high visual fidelity and even nowcast real weather conditions as simulations by streaming weather data into our framework.

Objectives. Congenital cytomegalovirus infection (cCMV) has been considered more prevalent among HIV-exposed children during pregnancy. Spanish national guidelines recommend the cCMV screening in these newborns. Nowadays, pregnant women have a better control of HIV infection compared to previous decades. We aim to analyze the prevalence and associated risk factors to cCMV in these children. Patients and methods. A retrospective cross-sectorial study was performed. All newborns exposed to HIV were assisted in a third-level hospital (2014-2020). Epidemiological and clinical data of the mother and newborn were recorded. Shell vial urine culture and/or CRP were performed along the two first weeks of life for the neonatal screening of cCMV. Results. Overall 69 newborns were enrolled. A high proportion (82.4%) of the mothers had been diagnosed with HIV before getting pregnant. All women received ART during the pregnancy. Median T-CD4 lymphocytes before delivery was 641/mm3 (IQR: 480-865) and the viral load was undetectable in 83.6%. Serological test for CMV along the first trimester of pregnancy was performed in 73.5% (positive IgG in 96%). There were no congenital cases of HIV neither cCMV (CI 95%:0-5.3%). Conclusions. The cCMV prevalence in newborns exposed to HIV was 0%, lower than reported before, probably related to a better and earlier ART during pregnancy, leading to a better immunological status.

Este estudio analiza los elementos descritos e implementados en el modelo de Educación Intercultural Bilingüe en Honduras, que tiene como resultado tácito la revitalización de la lengua pech¹. Se empleó una metodología cualitativa, apoyada por una investigación documental a través del método de análisis documental y la recopilación, procesamiento e interpretación de estadísticas educativas. Previo a esto, se realizó la investigación documental, donde se tomaron como muestra los documentos obtenidos en el proceso de recolección de datos. Luego, se aplicaron entrevistas estructuradas a la totalidad de las personas informantes (16 en total); también entrevistas a profundidad al personal directivo, docente, padres y madres de familia, y personas líderes comunitarias. Los datos cualitativos se procesaron a través de la transcripción de los audios y se triangularon los resultados de las entrevistas, los resultados de la investigación documental y la teoría. Los resultados principales muestran el quebrantamiento de la transmisión intergeneracional de la lengua pech. La población hablante representa el 4.19 %[1] de los 2,122 que habitan en el núcleo indígena donde se realizó este estudio. De manera paulatina, la lengua pech ha sido desplazada por la lengua oficial, el español, tanto en el hogar como en la escuela, el trabajo y la vida pública. Existen materiales educativos, pero son insuficientes para la enseñanza de la lectoescritura del pech, tomando en cuenta que en el Currículo Nacional Básico es considerada como segunda lengua. El modelo de educación intercultural bilingüe, que tiene como función primordial revitalizar la lengua pech e iniciar un proceso de alfabetización para la población, no logra su cometido. El valor cultural que tiene la lengua para los pech es símbolo identitario que agencia un potencial para su revitalización. [1] Según el censo de población y vivienda de Honduras correspondiente al año 2013, son 89 personas mayores de 60 años que habitan en el núcleo poblacional indígena en estudio.

Congenital Zika infection has been linked with a characteristic phenotype including neurologic sequelae. However, West syndrome has not been previously well described as a consequence. We aim to show this association through a retrospective descriptive study performed in Ecuador. Among 147 infants with congenital Zika infection, 7.5% suffered from West syndrome. Vigabatrin seems to be effective to control the spasms.

Existen fuertes críticas a la baja relación que existe entre los procesos de investigación y el contexto empresarial en las facultades, los programas de administración y las escuelas de negocios poco posicionados. Este documento tiene como objetivo determinar los temas relevantes en ciencias administrativas mediante la aplicación de análisis de redes para identificar las instituciones que manejan temas recurrentes, aquellas que abordan temas especializados y los territorios con investigación en el campo administrativo. Se identificaron las mejores facultades, programas de administración y escuelas de negocios a nivel mundial y nacional y a partir de esta selección, se construyó un modelo relacional de las interacciones entre las instituciones y las temáticas utilizando la teoría de redes. Se implementó este tipo de análisis dadoque permite la revisión sistemática y sus resultados se convierten en insumos que contribuyen a la posterior toma de decisiones por parte de las instituciones inmersas en este campo. Entre los resultados se encuentran como nodos institucionales notables la Escuela de Negocios de Columbia, la Escuela de Negocios Insead, la Universidad de Negocios Cornell, la Escuela de Negocios de Harvard y, finalmente, la Escuela de Gestión SLOAN del Massachusetts Institute of Technology. Finalmente, se identificaron como nodos temáticos relevantes aquellos relacionados con finanzas, emprendimiento, globalización y liderazgo.

Background Few congenital Zika syndrome (CZS) cases have been notified in Ecuador and, to our knowledge, there are no significant published studies dealing with their clinical evolution. We present a detailed clinical characterization of 21 children with congenital Zika virus (ZIKV) infection born in Ecuador who were followed up until September 2019. Methods We did a retrospective longitudinal study of children attended by the infectious disease specialists of Francisco Icaza Bustamante Children’s Hospital (Guayaquil) due to congenital ZIKV infection suspicion. The inclusion criteria consisted of laboratory confirmed diagnosis of congenital ZIKV infection. Results Sixteen of these 21 cases of congenital ZIKV infection showed clinical, neuroimaging and laboratory findings strongly suggestive of CZS and 5 children showed laboratory findings compatible with congenital ZIKV infection without congenital manifestations associated to CZS. All children with CZS showed neurodevelopmental delay, spasticity and hyperreflexia during follow-up, whereas the majority of them (14/15) experienced recurrent epileptic seizures and dysphagia (12/13). Two CZS cases died during follow-up. Visual evoked potential and hearing screening with acoustically evoked auditory brainstem response were abnormal in 50% and 37.5% of CZS cases, respectively. Congenital ZIKV infection without findings consistent with CZS at birth was not clinically relevant at 23 months of age in the five cases of our cohort. Conclusions Severe neurodevelopmental delay, severe microcephaly, epileptic seizures and dysphagia were present at 2 years of age in most CZS cases of our cohort.

An improved understanding of ecosystem functions is increasingly needed as ecosystem management moves towards optimizing their capacity to provide services to society. Such a task requires the characterization of ecosystem functions in strategic systems such as tropical mountain forests, which are also subject to pressure due to both global and local environmental changes. In particular, transformation of native forests into pastures or agriculture, has been regarded as the type of transformation with the largest effects in ecosystem regulating and provision functions. However, the effects of other transformations such as those associated with replacement of native with planted forests, have been less studied. To evaluate the effect of forest type on key-ecosystem functions related to water resources, we studied the dynamics of rainfall partitioning and nutrient circulation on a suite of representative forest types in neotropical mountain systems: two plantations of exotic fast-growing species and two types of native forests. Our results illustrate that, when considered in a per-basal unit area, water transmission to the forest floor is significantly higher in both native forests. Similarly, native forests are more effective on circulating nutrients on the ecosystem as they are better adapted to oligotrophic soils such as those occurring in tropical mountains. These results suggest that the replacement of native forests with exotic tree plantations can potentially impact hydrological regulation and the nutrient cycling in these high Andean lands, affecting both directly and indirectly the capacity of ecosystems to produce services to society.

Lightning activity has been recognized to have, historically, social and environmental consequences around the globe. This work analyzes the space-time distribution of lightning-densities (D) in an extended Central America region (ECA). World Wide Lightning Location Network data was analyzed to link D with dominant climate patterns over the ECA for 2012–2020. D associated with cold surges entering the tropics dominate during boreal winter. The highest D (hot-spots) was found to agree well with previously known sites, such as the “Catatumbo” in Venezuela; however, D was lower here due to different detection efficiencies. Previously reported hot-spots showed strong continental signals in CA; however, in this work, they were over the oceans near to coastlines, especially in the eastern tropical Pacific (ETP). Most cold-spots, implying a minimum of vulnerability to human impacts and to some industries, were situated in the Caribbean Sea side of Central America. The Mid-Summer-Drought and the Caribbean-Low-Level-Jet (CLLJ) markedly reduced the D during July-August. The CLLJ in the central CS and across the Yucatan and the southern Gulf of Mexico acts as a lid inhibiting convection due to its strong vertical shear during the boreal summer. The CLLJ vertical wind-shear and its extension to the Gulf of Papagayo also diminished convection and considerably decreased the D over a region extending westward into the ETP for at least 400–450 km. A simple physical mechanism to account for the coupling between the CLLJ, the MSD, and lightning activity is proposed for the latter region. UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones Geofísicas (CIGEFI)

Resumen Las exacerbaciones pulmonares de causa infecciosa son una de las mayores complicaciones en los pacientes con fibrosis quística (FQ). Estas se asocian a un progresivo aumento en la morbilidad y mortalidad. El tratamiento antimicrobiano se realiza dependiendo del microorganismo aislado. Con frecuencia se utilizan antimicrobianos β-lactámicos, los cuales no están exentos de reacciones adversas. A continuación, se describen dos casos de neutropenia tras el uso prolongado de cefepime en pacientes con FQ.

The Caribbean low‐level jet (CLLJ) is an important modulator of regional climate, especially precipitation, in the Caribbean and Central America. Previous work has inferred, due to their semiannual cycle, an association between CLLJ strength and meridional sea surface temperature (SST) gradients in the Caribbean Sea, suggesting that the SST gradients may control the intensity and vertical shear of the CLLJ. In addition, both the horizontal and vertical structure of the jet have been related to topographic effects via interaction with the mountains in Northern South America (NSA), including funneling effects and changes in the meridional geopotential gradient. Here we test these hypotheses, using an atmospheric general circulation model to perform a set of sensitivity experiments to examine the impact of both SST gradients and topography on the CLLJ. In one sensitivity experiment, we remove the meridional SST gradient over the Caribbean Sea and in the other, we flatten the mountains over NSA. Our results show that the SST gradient and topography have little or no impact on the jet intensity, vertical, and horizontal wind shears, contrary to previous works. However, our findings do not discount a possible one‐way coupling between the SST and the wind over the Caribbean Sea through friction force. We also examined an alternative approach based on barotropic instability to understand the CLLJ intensity, vertical, and horizontal wind shears. Our results show that the current hypothesis about the CLLJ must be reviewed in order to fully understand the atmospheric dynamics governing the Caribbean region. Consejo Superior Universitario Centroamericano/[805-A9-532]/CSUCA/Guatemala Agencia Sueca de Desarrollo Internacional/[805-A9-532]/ASDI/Suecia Universidad de Costa Rica/[805-B6-143]/UCR/Costa Rica Consejo Nacional para Investigaciones Científicas y Tecnológicas/[805-B6-143]/CONICIT/Costa Rica Ministerio de Ciencia, Tecnología y Telecomunicaciones/[805-B6-143]/MICITT/Costa Rica UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones Geofísicas (CIGEFI) UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencias del Mar y Limnología (CIMAR) UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Física

De acuerdo a referencias, existe una fuerte influencia del estrés con el desarrollo de enfermedades. En este trabajo se consideraron los atributos que hacen posible esa influencia para la elaboración de un modelo matemático que permite el planteamiento de escenarios que cambian con la frecuencia con la que un individuo implementa soluciones temporales para atender el estrés (pseudosoluciones) o cambia la frecuencia con la que recibe el tratamiento médico especializado para atender la enfermedad. Los resultados son concluyentes de la dinámica del comportamiento del sistema, permitiendo la configuración de escenarios en los que es posible que el paciente: 1) sane completamente, 2) alcance niveles estables de estrésenfermedad que puede sobrellevar sin riesgos pero con la implementación de diferentes pseudosoluciones y tratamientos médicos, o 3) ponga en riesgo su vida.

We explored the relationship between the precipitation anomalies during May to June as the first peak of the rainy season in the Pacific slope of Central America, and sea surface temperature (SST) fluctuations in the surrounding oceans, using canonical correlation analysis (CCA). With this approach, we studied variations in total precipitation, frequency of rainy days and the monthly occurrence of days with rainfall above (below) the 80th (20th) percentile, due to changes in the nearby SST. Composites of the sea-level pressure (SLP), geopotential heights (200 hPa), relative humidity (700 hPa), horizontal moisture flux and wind at 850 hPa were estimated to provide a dynamical analysis. The composites are calculated using the information obtained with CCA. In addition, we used a general circulation model forced with fixed SST to explore the sensitivity of the model to the SST patterns found using CCA. The results show that the SST over the tropical North Atlantic controls the precipitation fluctuations at interannual scales, due to its connection with the tropical upper tropospheric trough. Warmer (colder) temperatures result in SLP below normal in the Caribbean region, associated with an increase in the heights at 200 hPa. This vertical configuration reduces the wind shear between 850 and 200 hPa and increases the input of humidity to mid-levels, creating favourable conditions for deep convection, and favouring the generation of tropical cyclone activity. In the Pacific, a positive anomalous low-level moisture flux is observed from the ocean to the continental parts of the region and may enhance the formation of mesoscale systems. The classic prediction schemes show a lead time of 1 or 2 months; this is an advantage for climate services operative work. The atmospheric model outcomes replicate the main results found in the composite analysis, reflecting its potential use for model output statistics predictive schemes.

The local and condensed Fukui functions as well as the principle of hard and soft acids and bases were used to study the addition of free radicals to the exocyclic and endocyclic double bonds of seven monocyclic monoterpenes of formula C10H16. The results obtained showed that, in general, the most reactive double bond was the one with the most substituents on the double-bonded carbon atoms, and that the reaction of a double bond with an electrophile is a soft-soft interaction. The effects of substituents on the double-bonded carbon atoms and the stabilization of the monoterpenes were interpreted by invoking hyperconjugated structures, which led us to propose a simple rule: the larger the value of the Fukui function for the double bond, the greater the hyperconjugative stabilization and the susceptibility of the double bond to electrophilic attack. In general, our results are in good accordance with relevant experimental and theoretical results published in the literature. Graphical abstract The specific electrophilic addition to monocyclic monoterpenes.

ResumenEl presente artículo sintetiza los principales procesos histórico-científicos que permitieron el desarrollo de las primeras observaciones meteorológicas elaboradas en la región caribeña de Costa Rica. Se parte de las descripciones y mediciones realizadas por el Bachiller Osejo (1833) hasta la clausura parcial del Servicio Meteorológico y Sismológico Nacional (1949). Durante más de un siglo, dichas observaciones fueron elaboradas, sistematizadas y analizadas por diversos actores. Entre ellos, destacan científicos y estudiosos nacionales y extranjeros, instituciones científicas como el Instituto Físico-Geográfico Nacional y empresas como la United Fruit Company. Los datos recopilados fueron reanalizados e interpretados con el propósito de caracterizar el clima de la región en el pasado. Los resultados de este estudio aportan una línea base de comparación histórica ante el problema actual del cambio climático regional. AbstractThis article summarizes the main historical and scientific processes that allowed the development of the first meteorological observations made in the Caribbean region of Costa Rica. It is part of the descriptions and measurements made by Bachelor Osejo (1833) to the partial closure of the National Weather and Seismological Service (1949). For over a century, these observations were made, systematized and analyzed by various stakeholders. Among them are domestic and foreign scientists and scholars, scientific institutions such as the National Physical Geographic Institute and companies like United Fruit Company. The collected data were re-analyzed and interpreted in order to characterize the climate of the region in the past. The results of this study provide a baseline for historical comparison to the current problem of regional climate change.

A climatology of moisture sources linked with Central American precipitation was computed based upon Lagrangian trajectories for the analysis period 1980–2013. The response of the annual cycle of precipitation in terms of moisture supply from the sources was analysed. Regional precipitation patterns are mostly driven by moisture transport from the Caribbean Sea (CS). Moisture supply from the eastern tropical Pacific (ETPac) and northern South America (NSA) exhibits a strong seasonal pattern but weaker compared to CS. The regional distribution of rainfall is largely influenced by a local signal associated with surface fluxes during the first part of the rainy season, whereas large-scale dynamics forces rainfall during the second part of the rainy season. The Caribbean Low Level Jet (CLLJ) and the Chocó Jet (CJ) are the main conveyors of regional moisture, being key to define the seasonality of large-scale forced rainfall. Therefore, interannual variability of rainfall is highly dependent of the regional LLJs to the atmospheric variability modes. The El Niño–Southern Oscillation (ENSO) was found to be the dominant mode affecting moisture supply for Central American precipitation via the modulation of regional phenomena. Evaporative sources show opposite anomaly patterns during warm and cold ENSO phases, as a result of the strengthening and weakening, respectively, of the CLLJ during the summer months. Trends in both moisture supply and precipitation over the last three decades were computed, results suggest that precipitation trends are not homogeneous for Central America. Trends in moisture supply from the sources identified show a marked north–south seesaw, with an increasing supply from the CS Sea to northern Central America. Long-term trends in moisture supply are larger for the transition months (March and October). This might have important implications given that any changes in the conditions seen during the transition to the rainy season may induce stronger precipitation trends. Universidad de Costa Rica/[805-B3-600]/UCR/Costa Rica Universidad de Costa Rica/[805-B5-295]/UCR/Costa Rica Universidad de Costa Rica/[805-B0-065]/UCR/Costa Rica Universidad de Costa Rica/[805-A8-606]/UCR/Costa Rica Universidad de Costa Rica/[805-B0-130]/UCR/Costa Rica Universidad de Costa Rica/[805-A9-224]/UCR/Costa Rica Universidad de Costa Rica/[805-A7-002]/UCR/Costa Rica Universidad de Costa Rica/[805-B6-143]/UCR/Costa Rica Universidad de Costa Rica/[808-A9-180]/UCR/Costa Rica Environmental Physics Laboratory/[]/EPhysLab/España UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones Geofísicas (CIGEFI)

artículo científico -- Universidad de Costa Rica,Centro de Investigaciones Geofísicas. 2013. Este documento es privado debido a limitaciones de derechos de autor. Runoff climate change projections for the 21st century were calculated from a suite of 30 General Circulation Model (GCM) simulations for the A1B emission scenario in a 0.5 0.5 grid over Central America. The GCM data were downscaled using a version of the Bias Correction and Spatial Downscaling (BCSD) method and then used in the Variable Infiltration Capacity (VIC) macroscale hydrological model. The VIC model showed calibration skill in Honduras, Nicaragua, Costa Rica and Panama, but the results for some of the northern countries (Guatemala, El Salvador and Belize) and for the Caribbean coast of Central America was not satisfactory. Bias correction showed to remove effectively the biases in the GCMs. Results of the projected climate in the 2050–2099 period showed median significant reductions in precipitation (as much as 5–10%) and runoff (as much as 10–30%) in northern Central America. Therefore in this sub-region the prevalence of severe drought may increase significantly in the future under this emissions scenario. Northern Central America could warm as much as 3 C during 2050–2099 and southern Central America could reach increases as much as 4 C during the same period. The projected dry pattern over Central America is consistent with a southward displacement of the Intertropical Convergence Zone (ITCZ). In addition, downscaling of the NCEP/NCAR Reanalysis data from 1948 to 2012 and posterior run in VIC, for two locations in the northern and southern sub-regions of Central America, suggested that the annual runoff has been decreasing since ca. 1980, which is consistent with the sign of the runoff changes of the GCM projections. However, the Reanalysis 1980–2012 drying trends are generally much stronger than the corresponding GCM trends. Among the possible reasons for that discrepancy are model deficiencies, amplification of the trends due to constructive interference with natural modes of variability in the Reanalysis data, errors in the Reanalysis (modeled) precipitation data, and that the drying signal is more pronounced than predicted by the emissions scenario used. A few studies show that extrapolations of future climate from paleoclimatic indicators project a wetter climate in northern Central America, which is inconsistent with the modeling results presented here. However, these types of extrapolations should be done with caution, as the future climate responds to an extra forcing mechanism (anthropogenic) that was not present prehistorically and therefore the response could also be different than in the past. info:eu-repo/grantAgreement/Universidad de Costa Rica/Marine Science and Limnology Research Center (CIMAR)/808-A9-180/Costa Rica// info:eu-repo/grantAgreement/Universidad de Costa Rica/Center for Geophysical Research (CIGEFI)/805-A8-606/Costa Rica// info:eu-repo/grantAgreement/Universidad de Costa Rica/Center for Geophysical Research (CIGEFI)/805-A9-532/Costa Rica// info:eu-repo/grantAgreement/Universidad de Costa Rica/Center for Geophysical Research (CIGEFI)/805-A9-224/Costa Rica// info:eu-repo/grantAgreement/Florida Ice and Farm Company///Costa Rica// info:eu-repo/grantAgreement/Panamerican Institute of Geography and History//GEOF.02.2011/// UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones Geofísicas (CIGEFI)

An important goal of the Climate Variability and Predictability (CLIVAR) research on the American monsoon systems is to determine the sources and limits of predictability of warm season precipitation, with emphasis on weekly to interannual time scales. This paper reviews recent progress in the understanding of the American monsoon systems and identifies some of the future challenges that remain to improve warm season climate prediction. Much of the recent progress is derived from complementary international programs in North and South America, namely, the North American Monsoon Experiment (NAME) and the Monsoon Experiment South America (MESA), with the following common objectives: 1) to understand the key components of the American monsoon systems and their variability, 2) to determine the role of these systems in the global water cycle, 3) to improve observational datasets, and 4) to improve simulation and monthly-to-seasonal prediction of the monsoons and regional water resources. Among the recent observational advances highlighted in this paper are new insights into moisture transport processes, description of the structure and variability of the South American low-level jet, and resolution of the diurnal cycle of precipitation in the core monsoon regions. NAME and MESA are also driving major efforts in model development and hydrologic applications. Incorporated into the postfield phases of these projects are assessments of atmosphere–land surface interactions and model-based climate predictability experiments. As CLIVAR research on American monsoon systems evolves, a unified view of the climatic processes modulating continental warm season precipitation is beginning to emerge.

The collection of articles in this volume reviewing eastern tropical Pacific oceanography is briefly summarized, and updated references are given. The region is an unusual biological environment as a consequence of physical characteristics and patterns of forcing – including a strong and shallow thermocline, the ITCZ and coastal wind jets, equatorial upwelling, the Costa Rica Dome, eastern boundary and equatorial current systems, low iron input, inadequate ventilation of subthermocline waters, and dominance of ENSO-scale temporal variability. Remaining unanswered questions are presented.

The North American Monsoon Experiment (NAME) is an internationally coordinated process study aimed at determining the sources and limits of predictability of warm-season precipitation over North America. The scientific objectives of NAME are to promote a better understanding and more realistic simulation of warm-season convective processes in complex terrain, intraseasonal variability of the monsoon, and the response of the warm-season atmospheric circulation and precipitation patterns to slowly varying, potentially predictable surface boundary conditions. During the summer of 2004, the NAME community implemented an international (United States, Mexico, Central America), multiagency (NOAA, NASA, NSF, USDA) field experiment called NAME 2004. This article presents early results from the NAME 2004 campaign and describes how the NAME modeling community will leverage the NAME 2004 data to accelerate improvements in warm-season precipitation forecasts for North America.

In 2013, the vast majority of the monitored climate variables reported here maintained trends established in recent decades. ENSO was in a neutral state during the entire year, remaining mostly on the cool side of neutral with modest impacts on regional weather patterns around the world. This follows several years dominated by the effects of either La Niña or El Niño events. According to several independent analyses, 2013 was again among the 10 warmest years on record at the global scale, both at the Earths surface and through the troposphere. Some regions in the Southern Hemisphere had record or near-record high temperatures for the year. Australia observed its hottest year on record, while Argentina and New Zealand reported their second and third hottest years, respectively. In Antarctica, Amundsen-Scott South Pole Station reported its highest annual temperature since records began in 1957. At the opposite pole, the Arctic observed its seventh warmest year since records began in the early 20th century. At 20-m depth, record high temperatures were measured at some permafrost stations on the North Slope of Alaska and in the Brooks Range. In the Northern Hemisphere extratropics, anomalous meridional atmospheric circulation occurred throughout much of the year, leading to marked regional extremes of both temperature and precipitation. Cold temperature anomalies during winter across Eurasia were followed by warm spring temperature anomalies, which were linked to a new record low Eurasian snow cover extent in May. Minimum sea ice extent in the Arctic was the sixth lowest since satellite observations began in 1979. Including 2013, all seven lowest extents on record have occurred in the past seven years. Antarctica, on the other hand, had above-average sea ice extent throughout 2013, with 116 days of new daily high extent records, including a new daily maximum sea ice area of 19.57 million km2 reached on 1 October. ENSO-neutral conditions in the eastern central Pacific Ocean and a negative Pacific decadal oscillation pattern in the North Pacific had the largest impacts on the global sea surface temperature in 2013. The North Pacific reached a historic high temperature in 2013 and on balance the globally-averaged sea surface temperature was among the 10 highest on record. Overall, the salt content in nearsurface ocean waters increased while in intermediate waters it decreased. Global mean sea level continued to rise during 2013, on pace with a trend of 3.2 mm yr-1 over the past two decades. A portion of this trend (0.5 mm yr-1) has been attributed to natural variability associated with the Pacific decadal oscillation as well as to ongoing contributions from the melting of glaciers and ice sheets and ocean warming. Global tropical cyclone frequency during 2013 was slightly above average with a total of 94 storms, although the North Atlantic Basin had its quietest hurricane season since 1994. In the Western North Pacific Basin, Super Typhoon Haiyan, the deadliest tropical cyclone of 2013, had 1-minute sustained winds estimated to be 170 kt (87.5 m s-1) on 7 November, the highest wind speed ever assigned to a tropical cyclone. High storm surge was also associated with Haiyan as it made landfall over the central Philippines, an area where sea level is currently at historic highs, increasing by 200 mm since 1970. In the atmosphere, carbon dioxide, methane, and nitrous oxide all continued to increase in 2013. As in previous years, each of these major greenhouse gases once again reached historic high concentrations. In the Arctic, carbon dioxide and methane increased at the same rate as the global increase. These increases are likely due to export from lower latitudes rather than a consequence of increases in Arctic sources, such as thawing permafrost. At Mauna Loa, Hawaii, for the first time since measurements began in 1958, the daily average mixing ratio of carbon dioxide exceeded 400 ppm on 9 May. The state of these variables, along with dozens of others, and the 2013 climate conditions of regions around the world are discussed in further detail in this 24th edition of the State of the Climate series. © 2014, American Meteorological Society. All rights reserved.

The annual cycle of precipitation over the southern part of Mexico and Central America exhibits a bimodal distribution with maxima during June and September–October and a relative minimum during July and August, known as the midsummer drought (MSD). The MSD is not associated with the meridional migration of the intertropical convergence zone (ITCZ) and its double crossing over Central America but rather with fluctuations in the intensity and location of the eastern Pacific ITCZ. During the transition from intense to weak (weak to intense) convective activity, the trade winds over the Caribbean strengthen (weaken). Such acceleration in the trade winds is part of the dynamic response of the low-level atmosphere to the magnitude of the convective forcing in the ITCZ. The intensification of the trade winds during July and August and the orographic forcing of the mountains over most of Central America result in maximum precipitation along the Caribbean coast and minimum precipitation along the Pacific...

We report on balloon sonde measurements of water vapor and ozone using the cryogenic frost point hygrometer and electrochemical concentration cell ozonesondes made at Alajuela, Costa Rica (10.0 N, 84.2 W) during two NASA airborne campaigns: the Tropical Convective Systems and Processes (TCSP) mission in July 2005 and the Tropical Composition, Clouds, and Climate Coupling Experiment (TC4), July - August 2007. In both campaigns we found an upper troposphere that was frequently supersaturated but no evidence that deep convection had reached the tropopause. The balloon sondes were complemented by campaigns of 4 times daily high-resolution radiosondes from mid-June through mid-August in both years. The radiosonde data reveal vertically propagating equatorial waves that caused a large increase in the variability of temperature in the tropical tropopause layer (TTL). These waves episodically produced cold point tropopauses (CPTs) above 18 km, yet in neither campaign was saturation observed above approx 380 K or 17 km. The averages of the water vapor minima below this level were 5.2 ppmv in TCSP and 4.8 ppmv in TC4, and the individual profile minima all lay at or above approx 360 K. The average minima in this 360 C380 K layer provide a better estimate of the effective stratospheric entry value than the average mixing ratio at the CPT. We refer to this upper portion of the TTL as the tropopause saturation layer and consider it to be the locus of the final dehydration of nascent stratospheric air. As such, it is the local equivalent to the tape head of the water vapor tape recorder.

A relevant climate feature of the Intra-Americas Sea (IAS) is the low-level jet (IALLJ) dominating the IAS circulation, both in summer and winter; and yet it is practically unknown with regard to its nature, structure, interactions with mid-latitude and tropical phenomena, and its role in regional weather and climate. This paper updates IALLJ current knowledge and its contribution to IAS circulation-precipitation patterns and presents recent findings about the IALLJ based on first in situ observations during Phase 3 of the Experimento Climático en las Albercas de Agua Cálida (ECAC), an international field campaign to study IALLJ dynamics during July 2001. Nonhydrostatic fifth-generation Pennsylvania State University National Center for Atmospheric Research Mesoscale Model (MM5) simulations were compared with observations and reanalysis. Large-scale circulation patterns of the IALLJ northern hemisphere summer and winter components suggest that trades, and so the IALLJ, are responding to land-ocean thermal contrasts during the summer season of each continent. The IALLJ is a natural component of the American monsoons as a result of the continent's approximate north-south land distribution. During warm (cold) El Niño-Southern Oscillation phases, winds associated with the IALLJ core (IALLJC) are stronger (weaker) than normal, so precipitation anomalies are positive (negative) in the western Caribbean near Central America and negative (positive) in the central IAS. During the ECAC Phase 3, strong surface winds associated with the IALLJ induced upwelling, cooling down the sea surface temperature by 1-2 degrees C. The atmospheric mixed layer height reached 1 km near the surface wind maximum below the IALLJC. Observations indicate that primary water vapor advection takes place in a shallow layer between the IALLJC and the ocean surface. Latent heat flux peaked below the IALLJC. Neither the reanalysis nor MM5 captured the observed thermodynamic and kinematic IALLJ structure. So far, IALLJ knowledge is based on either dynamically initialized data or simulations of global (regional) models, which implies that a more systematic and scientific approach is needed to improve it. The Intra-Americas Study of Climate Processes is a great regional opportunity to address trough field work, modeling, and process studies, many of the IALLJ unknown features.

Este trabajo trata sobre la investigación realizada por el Ing. Luis Matamoros Sandoval, quien en 1902 publicó en Costa Rica sus investigaciones en Sismología en un artículo denominado "El interior de la corteza terrestre: una nueva teoría sobre el origen de los temblores". En su trabajo, Matamoros sigue la corriente de pensamiento aristotélica y la mezcla con las hipótesis del fraile español Benito Feijoo, quien propone la electricidad como la causante física de intensos terremotos con una gran área de percepción. Matamoros justifica sus resultados con matemática combinada con principios fundamentales de la física, los cuales explica en parte con cierto grado de dificultad, pues utiliza criterios y conceptos que no estaban soportados por el conocimiento de la física tradicional. Pese a los errores conceptuales, el trabajo es valioso por ser el primer intento científico local formal por explicar el origen de los temblores, proceso que aún en los grandes centros científicos de la época era fuente de continua especulación.

This work examines some of the effects of climate and climate variability in the Arenal River basin of Costa Rica, the site of the largest hydropower complex in the country. The Arenal system, which drains part of the north-central portion of Costa Rica covers a total area of approximately 493 km2 ; it is mainly managed for electric power generation and produces nearly a quarter of the total annual electricity in Costa Rica. Monthly, pentad (5-day means), and daily precipitation data are used to study signals associated with climate and shorter-term atmospheric disruptions in the basin. Although the study area is relatively small, strong spatial and temporal contrasts of precipitation patterns are found. A clear distinction in the seasonal distribution of precipitation is observed over short distances (~30–40 km), between the northwestern (NW) low lands of the basin compared to the southeastern (SE) sector. The former region exhibits a bimodal precipitation distribution, with maxima in June and September–October, and relative minima in July and December–April. The July minimum suggests a weak mid-summer drought or “veranillo” signal. The latter region has practically no dry season with the highest precipitation values occurring during the second part of the calendar year. As determined by principal component analysis of anomalies of monthly precipitation data, the main disruption of the normal pattern of precipitation appears to be related to the ENSO signal in the NW region, whereas the SE sector shows a positive correlation with Caribbean low-level wind changes. Some of the latter changes are associated with warm or cold ENSO episodes that seem to modulate wind intensities of the low-level jet over the Caribbean. Precipitation effects in the basin for selected extreme cases, such as that of hurricane Mitch, and other so-called “temporales” are also analyzed. The importance of these systems as fundamental components of the basin’s hydrological cycle is well established. ENSO related variability of the regional summer circulation (such as that of the low-level jet in the western Caribbean), and the appearance of cases of extreme strong trade winds during the winter circulation are also important forcing mechanisms for precipitation variability in the basin. In these cases, the interaction between the basin complex topography, and changes in the flow pattern and intensity seem to be of fundamental importance for precipitation variance. Some socioeconomic impacts of precipitation variability, as well as a discussion about the potential use of climate variability information for water management in the basin are presented Universidad de Costa Rica/[805-94-204]/UCR/Costa Rica Universidad de Costa Rica/[805-98-506]/UCR/Costa Rica Universidad de Costa Rica/[112-99-305]/UCR/Costa Rica UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones Geofísicas (CIGEFI) UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Física