Variability of winter frosts in Central South America: quantifying mechanisms with decision trees

Agricultural production in Central South America (CSA) is substantially influenced by frost events. This study charac¬terises and quantifies the physical processes leading to frost conditions in CSA from 1979 to 2022, focusing on three innovative aspects: regional frost properties, a novel multi-parametric upper-level jet description, and the quantification of underlying mechanisms through decision trees (DTs). The regionalisation analysis identifies five homogeneous frost regions in CSA. In all regions, the events tend to occur more frequently during the La Niña phase. Moreover, a significant increase in the frequency of widespread frost events has been observed in the Argentinean Pampas during the study period, primarily due to negative trends in minimum temperatures. Furthermore, the synoptic mechanisms triggering frosts, such as cold fronts and post-frontal anticyclones enhanced by subsidence near the subtropical jet (STJ) entrance, have not shown major long-term changes. To describe the jets, we compute six parameters for the STJ and seven for the polar front jet, including latitude, intensity, height, tilting, longitudinal extent, and branch number. DTs are used to identify key jet parameters linked to frost events, such as the latitude, longitudinal extent, and tilt of the Atlantic STJ. Frost likelihood increases when the STJ is north of 31°S, and the extension of the Atlantic STJ is longer than 35° and has a negative tilt. Finally, DTs focused on the onset and end of events highlight geopotential height anomalies and STJ extension as critical variables. These DTs provide concise and accessible information for agricultural decision-makers in CSA.European CommisionDepto. de Física de la Tierra y AstrofísicaFac. de Ciencias FísicasTRUEpubPagado por el auto

Summer upper‑level jets modulate the response of South American climate to ENSO

The upper-level jet stream is a critical element of atmospheric circulation, driving synoptic systems and extreme weather events. This study analyzes the impact of upper-level jets on South American (SA) summer temperature and precipitation under different El Niño-Southern Oscillation (ENSO) phases. Using the ERA5 reanalysis dataset from 1979 to 2022, we perform a daily multiparametric characterization of the jet stream, considering its spatial and temporal discontinuities. Besides latitude and intensity, we find that the departure and number of branches of the subtropical jet (STJ) and the longitudinal extent of the Pacific branch of the polar front jet (PFJ) are needed for their description. An additional parameter is required to characterize the STJ due to its absence on around 40% of summer days over SA. Moreover, we observe distinct long-term changes in PFJ parameters across different ocean basins. Three synoptic weather types (WTs) of the upper-level zonal wind are identified: normal conditions, a prominent STJ pattern, and a PFJ-only pattern. The latter pattern is associated with anticyclonic anomalies at 500hPa in the South Atlantic Ocean and an active SA Convergence Zone, which favors clear skies and warm (wet and cold) conditions in southern SA (Brazil). Consistently, the probability of experiencing warm spells in central Argentina is increased more than twofold. Finally, we detect that the temperature anomalies associated with the WTs are independent of the ENSO phase. However, ENSO modulates the frequency of the WTs: during La Niña (El Niño), the PFJ-only (prominent STJ) pattern is more common.Unión Europea. H2020Depto. de Física de la Tierra y AstrofísicaFac. de Ciencias FísicasTRUEpu

Educational platforms adapted to university teaching II: Mentimeter or Kahoot!?

Referencias Ros Velasco, J., Hernández Yáñez, L., Yousef Sandoval, L., González Pascual, C., Fragio Gistau, A., Zaragoza Bernal, J. M., Köwitz García, J., Cifuentes Matanza, A., Cervigón Rückauer, C., Manero Iglesias, J. B., Torregroza Lara, E. J., Jiménez Alcázar, J. F., Seguró Mendlewicz, M., Barros García, B., Esteban Nebot, V., García Villar, C., Sánchez San José, I., Jiménez Avedaño, D., Fernández Zavagno, J. P., Eljaiek Rodríguez, A. M., Hernández Albarracín, J. D., Moya Arriagada, I., Márquez Romero, M. Á., Garzón Costumero, X., Kalil el Aazzaoui, O., de Todo Orellana, R., Gómez Aliendres, K. A. y Mínguez Vicente, L. (2023). Plataformas educativas adaptadas a la enseñanza universitaria: ¿Mentimeter o Kahoot!?. Docta Complutense. Ros Velasco, J., Yousef Sandoval, L., González Pascual, C. y Köwitz García, J. (2024a). Preferencias del profesorado y el alumnado universitario en el uso de Mentimeter y Kahoot! Resultados de un estudio empírico comparativo. En Estrategias para la Transferencia de Conocimiento y la Innovación Educativa: Usos y aplicaciones de tecnologías innovadoras en la docencia (pp. 31-64). Dykinson. Ros Velasco, J., Yousef Sandoval, L., González Pascual, C. y Köwitz García, J. (2024b, en prensa). Seguridad e inclusividad en las apps Mentimeter y Kahoot! Comunicación & Métodos. Ros Velasco, J., Yousef Sandoval, L., González Pascual, C. y Köwitz García, J. (2024c, en prensa). Preferencias del profesorado y el alumnado en el uso de Mentimeter y Kahoot! Resultados de un estudio empírico en la enseñanza universitaria. En Innovación, investigación y transferencias ante la era de las Inteligencias Artificiales. Libro de resúmenes del congreso Internacional Nodos del Conocimiento 2023. Egregius Editorial.Memoria final del proyecto "Plataformas educativas adaptadas a la enseñanza universitaria II: ¿Mentimeter o Kahoot!?" (Nº 70), que es la continuación del proyecto "Plataformas educativas adaptadas a la enseñanza universitaria: ¿Mentimeter o Kahoot!?" (Nº 82, 2022-2023, https://hdl.handle.net/20.500.14352/87378). En esta secuela 1) seguimos recabando datos a través de la realización de experimentos con las apps Mentimeter y Kahoot! y 2) ejecutamos el plan de presentación/difusión de los resultados del proyecto Nº 82.Final report of the project "Educational platforms adapted to university teaching II: Mentimeter or Kahoot!?" (No. 70), which is the continuation of the project "Educational platforms adapted to university teaching: Mentimeter or Kahoot!?" (No. 82, 2022-2023, https://hdl.handle.net/20.500.14352/87378). In this sequel, we 1) continue collecting data by carrying out experiments with the Mentimeter and Kahoot! apps, and 2) execute the dissemination plan for the results of project No. 82.Vicerrectorado de Calidad, Proyectos de Innovación 2022-2024 Innova-Docencia UCMEuropean Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 847635Depto. de Filosofía y SociedadFac. de FilosofíaFALSEsubmittedAPC financiada por la UC