Jorge A. Amador

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.

Rainfall mechanisms in the Central American Isthmus are controlled by complex physical interactions across spatial and temporal scales, which are reflected on the dynamics of atmospheric circulation patterns affecting the region. However, physical mechanisms and their relationships with thermodynamic distributions connected to overturning circulations remain elusive. Here, a set of six recurrent daily atmospheric patterns, or weather types (WT), is defined using a k‐means++ clustering algorithm on standardized fields of Convective Available Potential Energy (CAPE) and winds at 925, 850, and 200 hPa. The relationships between these weather types, their temporal characteristics, and anomalous distributions of moisture flux divergence, equivalent potential temperature (saturated and unsaturated), and observed rainfall are used to describe physical processes controlling the latter, for all seasons. Regional observed rainfall is analysed from a set of 174 automatic stations from all countries from Mexico to Panama. By modulating vertically integrated moisture fluxes, these weather types, and the different climate drivers linked to them, control the temporal and spatial rainfall characteristics in the region, especially over the Pacific side of the isthmus. During some stages of the regional rainy season, described by two weather types, thermal anomalies in convective quasi‐equilibrium characteristic of the upward branch of the Hadley cell force westerly flow over Central America, enhancing rainfall. While during other stages, the enhancement of the trades and the displacement of convection to the ITCZ area over the eastern tropical Pacific, characteristic of the midsummer drought, diminishes rainfall. This study sets the stage for a better understanding of the mechanistic relationship between these weather types and rainfall characteristics in general, like onset, demise, and duration of rainy seasons. Hence, these results can inform process‐based model diagnostics aiming at bias‐correcting climate predictions at multiple timescales.

La construcción de las sociedades actuales ha sido posible gracias a los aportes de numerosos personajes a la política, a la economía, a las artes y a las ciencias. Considerado uno de los actores del proceso de independencia de Costa Rica, el bachiller Rafael Francisco Osejo tuvo una prolífica vida como político, educador y abogado; sin embargo, es relativamente poco lo que se conoce sobre su aporte al desarrollo de la ciencia de su época. Aquí se analizan sus escritos al tenor de la ciencia del periodo para responder a la pregunta: ¿fue Osejo un hombre de ciencia de su época? Se examinan y discuten sus dos principales obras relacionadas con temas como sismología, astronomía, matemática, física y meteorología, investigando, como complemento, los contenidos de algunas de las obras que este personaje tenía en su biblioteca. Osejo fue un personaje muy bien informado y educado en el conocimiento científico de su época. Logró, como hombre de ciencia, una activa participación personal e institucional en el inicio de una relevante época científica en el país.

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.

Surface and upper air observations and MM5v3 simulations examined the structure and inland penetration of sea breeze (SB) along the Grande de Tárcoles river basin (GTRB), central Pacific, Costa Rica, for two different intensity regimes of the Caribbean Low-Level Jet (CLLJ). Data comprise the period of 1 July to 16 September 2004 from Ticosonde-North American Monsoon Experiment, and a local University of Costa Rica-National Meteorological Institute field campaign. Maximum precipitation occurs between 14:00–17:00 LST, showing a time lag of 2 to 3 h after the temperature maximum, suggesting that local diurnal heating is key to convection. July–August precipitation exhibited a rainfall decrease along GTRB due to the SB dynamical processes interaction with a strong CLLJ. The SB maximum inland incursion was 24 km, with no evidence of its penetration into the Central Valley. The MM5v3 simulations for two convective and boundary layer (BL) schemes captured some SB structure features along the GTRB. Comparison of model results with observed data shows deficiencies in the model representation of the surface flow near coastal regions. Differences may be the result of time lag model’s poor responses to actual early morning BL sea–land temperature gradients. MM5v3 configurations used in this study resulted in biased wind speed simulations.

The evaluation of intraseasonal, seasonal, and annual variability of rainfall and temperature extremes, while using climate change scenarios data, is extremely important for socio-economic activities, such as water resources management. Costa Rica, a climate change hotspot, is largely dependent on rainfall for socioeconomic activities; hence, the relevance of this study. Based on the NEX-GDDP, rainfall and temperature range were analyzed for Costa Rica at the end of the century (2070–2099), while using 1970–1999 as a baseline for six available meteorological stations. Differences between the multimodel ensembles of two prospective scenarios (RCP 4.5 and 8.5) and the historical information were computed. This study highlights Costa Rica as an inflexion region for climate change impacts in Central America, for which projected scenarios suggest an early onset of the rainy season, and a decline in the mid-summer drought (MSD) minimum. The assessment of model data in some regions of Costa Rica, for which historical data were available, suggests that the latter does not capture a well-known regional climate feature, the MSD, in both precipitation and temperature range well. The availability of observed past data sources is a major limitation of this research; however, with the station data used, it is still possible to draw some conclusions regarding future climate in some regions of Costa Rica, especially in the northwest side of the country, where past data are consistent with model information, providing a more reliable picture of changes in climate there that has potential implications for socioeconomic sectors.

Hurricane Otto (2016) was characterised by remarkable meteorological features of relevance for the scientific community and society. Scientifically, among the most important attributes of Otto is that it underwent a rapid intensification (RI) process. For society, this cyclone severely impacted Costa Rica and Nicaragua, leaving enormous economic losses and many fatalities. In this study, a set of three numerical simulations are performed to examine the skill of model estimations in reproducing RI and trajectory of Hurricane Otto by comparing the results of a global model to a regional model using three different planetary boundary layer parameterizations (PBL). The objective is to set the basis for future studies that analyse the physical reasons why a particular simulation (associated with a certain model setup) performs better than others in terms of reproducing RI and trajectory. We use the regional model Weather Research and Forecasting—Advanced Research WRF (WRF-ARW) with boundary and initial conditions provided by the Global Forecast System (GFS) analysis (horizontal resolution of 0.5 degrees). The PBL used are the Medium Range Forecast, the Mellor-Yamada-Janjic (MYJ), and the Yonsei University (YSU) parameterizations. The regional model is run in three static domains with horizontal grid spacing of 27, 9 and 3 km, the latter covering the spacial extent of Otto during the simulation period. WRF-ARW results improve the GFS forecast, in almost every aspect evaluated in this study, particularly, the simulated trajectories in WRF-ARW show a better representation of the cyclone path and movement compared to GFS. Even though the MYJ experiment was the only one that exhibited an abrupt 24-h change in the storm’s surface wind, close to the 25-knot threshold, the YSU scheme presented the fastest intensification, closest to reality.

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.

This work comes to fill a fundamental gap in the history of Central American extreme climatic events by putting together qualitative and quantitative historical data and reanalysis information (the 20CR project) for the reconstruction of meteorological events associated with the floods that destroyed Cartago City in Costa Rica on October 27, 1891. This is a case study of a devastating 19th‐century disaster with profound social repercussions. Accounts, original historical documents, artistic depictions, instrumental data and photographs of the floods provide enough evidence of the severity of the meteorological system and the social dimension of the disaster. The historical information details the continuous rains, as well as the area covered by mud, trees and big rocks in the Cartago Valley due to the Reventado River flooding. Based on the above sources, the destruction of houses, roads and civil infrastructure is described, and the meteorological conditions of the period are analysed. By using documentary, instrumental and 20CR data, the potential direct or indirect effects of some tropical atmospheric systems were studied for the period October 22–29, 1891. Results indicate that the most probable cause of the rains and floods was a Caribbean “temporal,” a system that strikes the region frequently. This phenomenon, according to 20CR data, was modulated by a high‐pressure system over the Gulf of Mexico and brought abundant moisture and high winds to the region. Two women and three children were officially confirmed to have died; however, other sources imply many more victims and disappearances. The interventions by the government and local people were crucial for the restoration of the flooded part of Cartago City from the tragedy. The rains and floods left more than 120 seriously damaged or destroyed houses, and severe economic losses equivalent to potentially much more than 49 MM U.S. dollars.