Revista de Biología Tropical

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https://hdl.handle.net/10669/15280

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Algunas características de las corrientes marinas en el Golfo de Nicoya, Costa Rica
(2016-10-13) Lizano Rodríguez, Omar Gerardo; Alfaro Martínez, Eric J.
The spatial and vertical structure of the water currents and its relationship with the tidal cycles were studied using current meters in the Gulf of Nicoya. In the upper gulf, the vertical marine current differences increase as the depth increases. The water column at the station near Chira Island (upper gulf) shows the smaller changes in currents and in temperature. The flow at the station between San Lucas Island and Puntarenas (middle gulf) is the most stratified in this region. Currents with magnitudes over 100 cm/seg were measured during spring tides. Changes in the lags of the surface and bottom tidal flows were measured on the order of 100 minutes. In general, in this upper region the flows are toward the head of the gulf when the tide is flooding and toward the mouth when the tide is ebbing. In the lower gulf the circulation is more complex. Along an axis between Tárcoles and Negritos Islands, changes of velocity vectors are identified between surface and bottom. The current rotates in a different way in the water column in this region and their patterns cannot be explained only by the tidal cycles predicted for Puntarenas. These results demonstrate that the spatial and vertical variation of the marine currents of the Gulf of Nicoya is not only related to the thermohaline structure, but also to the tidal cycles and tide ranges that take place in this estuary.
Algunas relaciones entre las zonas de surgencia del Pacífico Centroamericano y los Océanos Pacífico y Atlántico Tropical
(2001-02) Alfaro Martínez, Eric J.; Lizano Rodríguez, Omar Gerardo
Con el fin de explorar la influencia de los océanos tropicales sobre las Anomalías de la Temperatura Superficial del Mar (ATSM) de la costa pacífica centroamericana, se ajustó un modelo de función de transferencia a las series de ATSM de los Golfos de Tehuantepec, Papagayo, Panamá y Quepos, usando como variables independientes los índices Niño 3.4, Atlántico Tropical Norte y Sur. Estos modelos concluyeron que la principal influencia sobre la región, al compararla con los otros índices, la ejerce el índice Niño 3.4 pues mostró correlaciones positivas con todas las series de ATSM, lo cual refleja una influencia de este índice sobre la profundidad relativa de la termoclina frente a la costa del Pacífico centroamericano.
Atmospheric forcing of cool subsurface water events in Bahía Culebra, Gulf of Papagayo, Costa Rica
(Revista Biología Tropical, 60 (2): 173-186, 2012-04) Alfaro Martínez, Eric J.; Cortés Núñez, Jorge
Bahía Culebra, at Gulf of Papagayo on the north Pacific coast of Costa Rica, is an area of seasonal upwelling where more intense cooling events may occur during some boreal winter weeks mainly. To study these extreme cool events, records of nine sea subsurface temperature stations from 1998 to 2010 were analyzed. Five events associated with extremely cool temperatures in this region were identified from these records and taken as study cases. Sea temperatures decreased about 8-9ºC during these events and occurred while cold fronts were present in the Caribbean, with strong trade wind conditions over Central America. These strong wind conditions may have favored the offshore displacement of the sea surface water. The axis of Bahía Culebra runs northeastsouthwest, a condition that favors and triggers cool water events, mainly because the displaced water is replaced by water from deeper levels. Rev. Biol. Trop. 60 (Suppl. 2): 173-186. Epub 2012 April 01.
Caracterización del “veranillo” en dos cuencas de la vertiente del Pacífico de Costa Rica, América Central
(2014-09) Alfaro Martínez, Eric J.
La región de los Mares Intra-Americanos está caracterizada por fenómenos climáticos raramente observados en regiones tropicales, uno de ellos es el llamado “veranillo” o “canícula”. Sobre la vertiente del Pacífico de América Central, el ciclo anual de la precipitación está caracterizado por dos máximos, uno en junio y el otro, mayor que el primero, en setiembre-octubre, con una época seca de noviembre a mayo y un periodo corto de reducción de precipitaciones durante julio-agosto (veranillo o canícula). Se estudiaron siete registros diarios de precipitación, pertenecientes las estaciones ubicadas en dos cuencas importantes de Costa Rica, río Grande de Tárcoles y río Tempisque, para caracterizar el veranillo en el periodo 1937-2012. Dentro de los aspectos considerados, está el inicio, duración y final del evento, la fecha del mínimo, así como su intensidad y magnitud. Se exploró luego la modulación de estos aspectos debido a fuentes de variabilidad climática tales como el Pacífico Ecuatorial del Este, en donde se observó que condiciones cálidas (frías) del índice Niño 3.4, tienden a estar relacionadas con eventos más secos (más lluviosos) de veranillos.
Ciclo diario y anual de variables troposféricas y oceánicas en la Isla del Coco, Costa Rica
(2008-08) Alfaro Martínez, Eric J.
Se recolectaron los registros meteorológicos de las estaciones que funcionaron en la Isla del Coco, Costa Rica, pertenecientes a una estación meteorológica automática y a dos pluviógrafos, para el periodo 1997 – 2005. También se obtuvieron las series de tiempo de diferentes de registros históricos y de los puntos de rejilla más cercanos a la isla de distintas bases de datos geofísicas públicas. Se hizo énfasis en la recolección de registros de precipitación, viento, radiación, humedad relativa, temperatura superficial del aire y del mar. Para todas las variables con registros de datos horarios, se obtuvieron sus ciclos diarios y anuales y se estudió sus características intra-estacionales, tales como máximos, mínimos y épocas de transición; y se hizo la comparación de los registros de precipitación de las estaciones con los registros de las bases de datos con mayor escala espacial. Se observa que las variaciones estacionales en la Isla del Coco están asociadas a la migración meridional de la Zona de Convergencia Inter-Tropical, ya que la isla se encuentra bajo su influencia prácticamente desde la primavera hasta el otoño boreal.
Clima y temperatura sub-superficial del mar en Bahía Culebra, Golfo de Papagayo, Costa Rica
(Revista Biología Tropical, 60 (2): 159-171, 2012-04) Alfaro Martínez, Eric J.; Alvarado Barrientos, Juan José; Jiménez Centeno, Carlos; León, Alberto; Sánchez Noguera, Celeste; Nivia Ruiz, Jaime; Cortés Núñez, Jorge; Ruiz Campos, Eleazar
Bahía Culebra, Golfo de Papagayo, Costa Rica is a seasonal upwelling area. To determine the relationship of climate and the subsurface temperature variability at Bahía Culebra, we analyzed nine records of sea subsurface temperature from the Bay, continuously recorded from 1998 to 2010. The analysis characterized the annual cycle and explored the influence of different climate variability sources on the subsurface sea temperature and air temperature recorded in Bahía Culebra. Data from an automatic meteorological station in the bay were studied, obtaining the annual and daily cycle for air surface temperature and wind speed. Sea surface temperature (SST) trend from 1854 to 2011 was calculated from reanalysis for the region that coverts 9-11°N, 85-87°W. Because of the positive SST trend identified in this region, results showed that annual and daily cycles in Bahía Culebra should be studied under a warming scenario since 1854, that is coherent with the global warming results and its climate variability is influenced by El Niño-Southern Oscillation (ENSO) in the Equatorial Pacific and by atmospheric forcing triggered by climate variability with Atlantic Ocean origin, because warm (cold) events in Bahía Culebra tend to occur in concordance with positive & negative (negative & positive) anomalies in Niño 3.4 (NAO) index. Rev. Biol. Trop. 60 (Suppl. 2): 159-171. Epub 2012 April 01.
Climate of an oceanic island in the Eastern Pacific: Isla del Coco, Costa Rica, Central America
(Universidad de Costa Rica) Alfaro Martínez, Eric J.; Hidalgo León, Hugo G.
Studies of atmosphere-ocean interaction in the Pacific of Costa Rican are scarce. To identify oceanographic systems that may be influencing climate near Cocos Island (Eastern Tropical Pacific Seascape) we conducted six scientific expeditions between 2007 and 2012. Two automated weather stations were set near Chatham and Wafer bays during the expeditions. Data included records from National Meteorological Institute, Global Precipitation Climatology Project (GPCP) and Extended Reconstructed Sea Surface Temperature (ERSST). The climate is typical of the Eastern Tropical Pacific. Its seasonality is driven by precipitation variability associated with meridional migration of the Intertropical Convergence Zone. The seasonal cycle has two peaks, in May and July, a relative minimum between them in June, and the absolute minimum in February. Most of the precipitation is recorded from April to November. Most rain events have short duration and low intensity. An SST trend was observed from January 1854 to December 2013, coherent with regional warming temperature observations. From 1998 to 2013 there were changes in distributions of almost all meteorological parameters. The combination of these factors resulted in higher evapotranspiration values through the daily cycle, especially during the night time. Precipitation (P) positive anomalies tended to be associated with positive air surface temperature (AST) and SST anomalies and negative global radiation (GR) anomalies. Negative P anomalies tended to be associated with negative AST, SST and positive GR anomalies. Relative humidity (RH) negative anomalies tend to be associated with positive wind speed (WS) anomalies, and the WS effect is opposite for positive RH anomalies. During the cold Niño 3 condition of October 2007, negative P, AST, SST and RH anomalies were observed in concordance with positive WS and GR anomalies, in agreement with the conceptual model of climate system response at Isla del Coco to cold ENSO conditions.
Composición de sedimentos en las zonas costeras de Costa Rica utilizando Fluorescencia de Rayos-X (FRX)
(2004-04) Salazar Matarrita, Alfonso; Lizano Rodríguez, Omar Gerardo; Alfaro Martínez, Eric J.
Utilizando Fluorescencia de Rayos-X dispersiva en energía, que permite la evaluación simultánea de los isótopos estables de trece elementos, se analizaron setenta y cuatro muestras de sedimentos marinos de las regiones intermareales para las costas del Caribe y del Pacífico Norte, Central y Sur de Costa Rica. Los elementos calcio y hierro fueron los más abundantes y son representativos delorigen de la formación natural del sedimento, estando el primero asociado a procesos biogénicos, tales como sistemas arrecifales coralinos cercanos al sitio de muestreo y el segundo esta asociado mas bien a sedimentos de carácter litogénico. En general, las playas del Pacífico Norte mostraron la mayor concentración de calcio lo que es indicativo de mayor existencia de estructuras arrecifales en sus alrededores. El análisis de los elementos traza, ligados a un origen terrígeno, muestras un patrón similar al hierro en la mayoría de las regiones. Las playas del Pacífico Central y Sur muestran las mayores concentraciones de estos elementos traza, indicando una mayor contribución terrígena y/o poco contribución de carbonato de calcio debido al escaso desarrollo de estructuras coralinas en estas regiones. Por último, el análisis no mostró evidencia de contaminación antropogénica y solo una sección al norte de la Playa Puerto Viejo presentaron concentraciones altas de plomo zinc y titanio, lo cual podría estar ligado a fuentes hidrotermales en esta región.
Diccionario histórico-toponímico de la Isla del Coco, Costa Rica
(2012-09) Díaz Bolaños, Ronald Eduardo; Alfaro Martínez, Eric J.; Ugalde Quesada, Alexia
Many names have been used for the different places of Isla del Coco, and some have changed over time. Studying different historic sources, seventy-six names of the main topographic features were collected for Isla del Coco National Park, Costa Rica. These names could be grouped in four main categories: those associated with the British traveler’s visitations, the ones related with the republican period of Costa Rica and those linked with the island’s terrestrial and marine flora and fauna. The methodology used allowed the proper documentation of seventy-one names. This methodology and the publication of this dictionary intend to generate a feedback regarding the naming of topographic characters of Isla del Coco.
Distribución espacial de radionucleídos en sedimentos marinos de Bahía Culebra y el Golfo de Nicoya, Pacífico, Costa Rica
(2008-12-01) Lizano Rodríguez, Omar Gerardo; Loría Meneses, Luis Guillermo; Alfaro Martínez, Eric J.; Badilla Figueroa, Mauricio
Los radionucleídos naturales y artificiales de los sedimentos marinos fueron estudiados en Bahía de Culebra y en el Golfo de Nicoya, ambos en la costa Pacífica de Costa Rica. Muestreos en un humedal y en una isla oceánica, fueron usados como sitios de referencia. La concentración de los elementos radiactivos originados durante la formación de nuestro planeta disminuye en los bloques continentales viejos. Dado que una isla oceánica es de formación más joven, se espera encontrar altas concentraciones de estas sustancias, como muestran los resultados de este estudio. Los ámbitos de estos elementos son considerados normales según los informes globales. Algunos, como el Potasio-40, parecieran tener una contribución antropogénica en el Golfo de Nicoya, posiblemente relacionada a las actividades que se desarrollan en sus cuencas hidrográficas adyacentes. En todos los sitios de muestreo, la concentración del elemento artificial Cesio-137 se ha detectado dentro de ámbitos normales y sus valores son muy similares a los medidos en la costa y en el interior del país en estudios anteriores.
Global Model selection for evaluation of Climate Change projections in the Eastern Tropical Pacific Seascape
(Revista Biología Tropical 60 (3): 67-81, 2012-11) Hidalgo León, Hugo G.; Alfaro Martínez, Eric J.
Two methods for selecting a subset of simulations and/or general circulation models (GCMs) from a set of 30 available simulations are compared: 1) Selecting the models based on their performance on reproducing 20th century climate, and 2) random sampling. In the first case, it was found that the performance methodology is very sensitive to the type and number of metrics used to rank the models and therefore the results are not robust to these conditions. In general, including more models in a multi-model ensemble according to their rank (of skill in reproducing 20th century climate) results in an increase in the multi-model skill up to a certain point and then the inclusion of more models degrades the skill of the multi-model ensemble. In a similar fashion when the models are introduced in the ensemble at random, there is a point where the inclusion of more models does not change significantly the skill of the multi-model ensemble. For precipitation the subset of models that produces the maximum skill in reproducing 20th century climate also showed some skill in reproducing the climate change projections of the multi-model ensemble of all simulations. For temperature, more models/simulations are needed to be included in the ensemble (at the expense of a decrease in the skill of reproducing the climate of the 20th century for the selection based on their ranks). For precipitation and temperature the use of 7 simulations out of 30 resulted in the maximum skill for both approaches to introduce the models.
Humedales del Parque Nacional Chirripó, Costa Rica: características, relaciones geomorfológicas y escenarios de cambio climático
(2018-12) Veas Ayala, Néstor; Quesada Román, Adolfo; Hidalgo León, Hugo G.; Alfaro Martínez, Eric J.
The geomorphological, climatological and hydrological characteristics of the high Andean wetlands of the Chirripó National Park (PNCh) are analyzed. The PNCh is located in south-central Costa Rica, Central America. This analysis includes a geomorphological survey on a 1: 25 000 scale of the relief forms and processes, particularly those of glacial origin. The National Wetland Inventory carried out by the Wetlands Project (UNDP-SINAC-GEF) was also used, along with different climate change projections corresponding to the scenarios for the 2039-2059 and 2079-2099 horizons. The main objective is to characterize the current state of these ecosystems, to explain how and why they are formed, as well as to assess the possible implications in the hydrological cycle and the water supply of these wetlands due to future climate variations. The results showed the relevance of these natural reservoirs in maintaining the ecological dynamics of the PNCh. We also studied the services of water provision and regulation of the hydrological cycle in the basins that compose this protected area.
Un método para evaluar el enriquecimiento de metales en sedimentos marinos en Costa Rica
(Revista Biología Tropical 60 (2): 197-211, 2012-04-01) Lizano Rodríguez, Omar Gerardo; Alfaro Martínez, Eric J.; Salazar Matarrita, Alfonso
A method to evaluate metal enrichment in marine sediments. In order to evaluate metal enrichment in sediments , a method is proposed and tested in Bahia Culebra and the Golfo de Nicoya, Costa Rica through the normalization of the elements against aluminum, and by linear regression of the logarithm of the concentrations of different elements respect to aluminum. The distributions of the elements manganese, and strontium of Bahía Culebra did not satisfy the tests of normalization and linear regression, indicating a nonnatural distribution or enrichment of these elements in this region. In the Golfo de Nicoya the elements copper , zinc , rubidium and the strontium did not satisfy the test of normality or the linear regression with respect to aluminum, indicating a possible enrichment of these elements. The majority of the concentrations of the elements in two sample sites, with the exception of chromium, are within the natural ranges in rocks or clays of marine sediments, and within the concentration ranges of other studies done in these same regions. Chromium has average values beyond the natural concentrations, the values of some samples in the Golfo de Nicoya are up to 10 times greater than the concentration value of a typical bay with high contamination of this element.
Regional precipitation estimations in Central America using the Weather Research and Forecast model
(2018-04) Maldonado Mora, Tito José; Alfaro Martínez, Eric J.; Amador Astúa, Jorge Alberto; Rutgersson, Anna
Using the regional climate model WRF, and the NCEP-NCAR Reanalysis Project data as boundary and initial conditions, regional precipitation for Central America was estimated by means of the dynamical downscaling technique for two selected periods: January 2000 and September 2007. Four-nested domains, d01, d02, d03 and d04 with a grid-resolution of 90 km, 30 km, 10 km, and 3.3 km respectively, were configured over this region. The runs were reinitialized every 5 days with 6 h of spin-up time for adjustment of the model. A total of eight experiments (four per month) were tested in order to study: a) two important Cumulus Parameterization Schemes (CPS): Kain-Fritsch (KF) and Grell-Devenyi (GD); and b) the physical interaction between nested domains (one- and two-way nesting), during each simulated month. The modeled precipitation was in agreement with observations for January 2000, and also captured the mean climate features of rainfall concerning magnitude, and spatial distribution, such as the particular precipitation contrast between the Pacific and the Caribbean coast. Outputs of the coarse domains (d01, d02, and d03) for September 2007 revealed differences between experiments within the domains when a visual comparison of the spatial distribution was made. However, for the inner grid (d04), all the experiments, showed a similar spatial distribution and magnitude estimation, mainly in those runs using one-way nesting configuration. The results for the month of September differed substantially with the observations, which could be related to associated deficiencies in the boundary condition that do not reproduce well the transition periods from warm to cold ENSO episodes for the selected periods of study. In all the experiments, the KF scheme calculated more precipitation than the GD scheme and it was associated to the ability of the GD scheme to reproduce spotty but intense rainfall, and apparently, this scheme was reluctant to activate, showing frequent events of low intensity rain. However, when rainfall did develop, it was very intense. Also, the time series did not replicate specific precipitation events. Thus, the 5-days integration period used in this study was not enough to reproduce short-period precipitation events. Finally, physical interaction issues between the nested domains were reflected in discontinuities in the precipitation field, which have been associated with mass field adjustment in the CPS. Rev. Biol. Trop. 66(Suppl. 1): S231-S254. Epub 2018 April 01.
Revisión y comparación de escenarios de cambio climático para el Parque Nacional Isla del Coco, Costa Rica
(Revista Biología Tropical 60(3): 83-112, 2012-11) Maldonado Mora, Tito José; Alfaro Martínez, Eric J.
Different climate change scenarios were revised and compared for Cocos Island National Park, Costa Rica. They were generated using different tools (MAGICC/SCENGEN, PRECIS and SDSM) and for the 2080 (2070- 2099) time slice. Results shown in general a high dependence with the General Circulation Model, the downscaling technique and the socioeconomic scenario used. All scenarios presented an increase in mean and variance of the air surface temperature annual cycle. That result is also consistent with a future global warming scenario. Results for rainfall are different among each other. Most of the scenarios show an increase in the mean annual rainfall accumulation. However, it is not possible to establish a clear trend when annual variability is considered, mainly because almost all of the scenarios studied projected an increase in the annual rainfall accumulates. Citation: Maldonado, T.J. & E.J. Alfaro. 2012. Revisión y comparación de escenarios de Cambio Climático para el Parque Nacional Isla del Coco, Costa Rica.

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