Person:
Losada Doval, Teresa

First Name

Teresa

Last Name

Losada Doval

URI

https://hdl.handle.net/20.500.14352/75063

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Ciencias Físicas

Department

Física de la Tierra y Astrofísica

Area

Física de la Tierra

Identifiers

Full item page

Search Results

Now showing 1 - 10 of 14

Impacts of the Atlantic Equatorial Mode in a warmer climate
(Climate dynamics, 2015) Mohino Harris, Elsa; Losada Doval, Teresa
The main source of sea surface temperature (SST) variability in the Tropical Atlantic at interannual time scales is the Equatorial Mode or Atlantic El Niño. It has been shown to affect the adjacent continents and also remote regions, leading to a weakened Indian Monsoon and promoting La Niña-type anomalies over the Pacific. However, its effects in a warmer climate are unknown. This work analyses the impact of the Equatorial Mode at the end of the twenty first century by means of sensitivity experiments with an atmosphere general circulation model. The prescribed boundary conditions for the future climate are based on the outputs from models participating in the coupled model intercomparison project-phase V. Our results suggest that even if the characteristics of the Equatorial Mode at the end of the twenty first century remained equal to those of the twentieth century, there will be an eastward shift of the main rainfall positive anomalies in the Tropical Atlantic and a weakening of the negative rainfall anomalies over the Asian monsoon due to the change in climatological SSTs. We also show that extratropical surface temperature anomalies over land related to the mode will change in regions like Southwestern Europe, East Australia, Asia or North America due to the eastward shift of the sea level pressure systems and related surface winds.
Relationships among Intermodel Spread and Biases in Tropical Atlantic Sea Surface Temperatures
(Journal of Climate, 2019) Mohino Harris, Elsa; Rodríguez De Fonseca, María Belén; Mechoso, C. Roberto; Losada Doval, Teresa; Polo Sánchez, Irene
State-of-the-art general circulation models show important systematic errors in their simulation of sea surface temperatures (SST), especially in the tropical Atlantic. In this work the spread in the simulation of climatological SST in the tropical Atlantic by 24 CMIP5 models is examined, and its relationship with the mean systematic biases in the region is explored. The modes of intermodel variability are estimated by applying principal component (PC) analysis to the SSTs in the region 70ºW–20ºE, 20ºS–20ºN. The intermodel variability is approximately explained by the first three modes. The first mode is related to warmer SSTs in the basin, shows worldwide connections with same-signed loads over most of the tropics, and is connected with lower low cloud cover over the eastern parts of the subtropical oceans. The second mode is restricted to the Atlantic, where it shows negative and positive loads to the north and south of the equator, respectively, and is connected to a too weak Atlantic meridional overturning circulation (AMOC). The third mode is related to the double intertropical convergence zone bias in the Pacific and to an interhemispheric asymmetry in the net radiation at the top of the atmosphere. The structure of the second mode is closer to the mean bias than that of the others in the tropical Atlantic, suggesting that model difficulties with the AMOC contribute to the regional biases. State-of-the-art general circulation models show important systematic errors in their simulation of sea surface tem- peratures (SST), especially in the tropical Atlantic. In this work the spread in the simulation of climatological SST in the tropical Atlantic by 24 CMIP5 models is examined, and its relationship with the mean systematic biases in the region is explored. The modes of intermodel variability are estimated by applying principal component (PC) analysis to the SSTs in the region 708W–208E, 208S–208N. The intermodel variability is approximately explained by the first three modes. The first mode is related to warmer SSTs in the basin, shows worldwide connections with same-signed loads over most of the tropics, and is connected with lower low cloud cover over the eastern parts of the subtropical oceans. The second mode is restricted to the Atlantic, where it shows negative and positive loads to the north and south of the equator, respectively, and is connected to a too weak Atlantic meridional overturning circulation (AMOC). The third mode is related to the double intertropical convergence zone bias in the Pacific and to an interhemispheric asymmetry in the net radiation at the top of the atmosphere. The structure of the second mode is closer to the mean bias than that of the others in the tropical Atlantic, suggesting that model difficulties with the AMOC contribute to the regional biases.
Tropical atmospheric response of Atlantic Niños to changes in the ocean background state
(2023) Svendsen, Lea; Rodríguez De Fonseca, María Belén; Mohino Harris, Elsa; Crespo, Lander; Losada Doval, Teresa
Since the 1970s, Atlantic Ninos during boreal summer have been linked to Pacific La Ninas the following winter. Earlier studies have explained the appearance of the Atlantic-Pacific teleconnection with changing Atlantic Nino configurations. Here we find that the non-stationarity of this teleconnection can also be explained by changes in the ocean background state, without changing the Atlantic Nino configuration. Experiments with different atmospheric general circulation models are performed where the same Atlantic Nino pattern is prescribed to different global ocean background states. The 1975-1985 global mean sea surface temperature forces a Walker Circulation response and low-level convergence over the Maritime Continent, increasing the chance of triggering a La Nina-like event in the Pacific. These results suggest that ENSO-predictions could be improved in certain periods by considering tropical Atlantic variability. The Atlantic Nino is the main climate variability phenomenon in the equatorial Atlantic and has a strong influence on local and remote climate. Since the 1970s, warm Atlantic Nino events in June-August have been linked to cool La Nina events developing in the equatorial Pacific the following December-February. The appearance of this Atlantic-Pacific link has been explained by changes in the temperature pattern of Atlantic Ninos but, so far, no study has analyzed the role of mean state changes. In this study we demonstrate the contribution of changes in the mean background surface temperatures of the global oceans to the appearance of this Atlantic-Pacific link. These results imply that under certain global ocean background conditions, we should use information about the Atlantic Nino to improve seasonal forecasts of El Nino and La Nina events. An Atlantic Nino in summer can produce atmospheric conditions of a La Nina-like event in the Pacific under certain ocean background statesThe ocean background state is of similar importance as the Atlantic Nino pattern for modifying the Atlantic Nino-Pacific teleconnectionAn Atlantic Nino intensifies easterly wind anomalies over the western equatorial Pacific when the Pacific has a warmer background state
A shift in the wind regime of the southern end of the Canary upwelling system at the turn of the 20th century
(Journal of geophysical research-oceans, 2021) Gallego, D.; García Herrera, Ricardo Francisco; Losada Doval, Teresa; Mohino Harris, Elsa; Rodríguez De Fonseca, María Belén
In this study, we make use of historical wind direction observations to assemble an instrumental upwelling index (DUI) at the southern end of the Canary Current Upwelling System. The DUI covers the period between 1825 and 2014 and, unlike other upwelling indices, it does not rely neither in wind speed nor in reanalyzed data. In this sense, the DUI can be regarded as an instrumental index. Additionally, it avoids the suspected bias toward increasing wind speed of historical wind observations documented in previous research. Our results indicate that the frequency of the alongshore winds at the west coast of Africa between 10°N and 20°N measured by the DUI is significantly related with the wind stress and therefore the upwelling intensity in this region. The DUI presents a significant variability both at interannual and decadal timescales. We have not found any significant trend for the 20th century. However, when the entire length of the series is considered, a large shift toward more frequent alongshore winds is evidenced as a result of several decade-long fluctuations which took place between the late 19th century and the beginning of the 20th century. This fact would imply that a significant change in the upwelling intensity at the southern end of the Canary Current Upwelling System should have occurred at the turn of the 20th century.
Changes in interannual tropical Atlantic-Pacific basin interactions modulated by a South Atlantic cooling
(Journal of climate, 2022) Losada Doval, Teresa; Rodríguez De Fonseca, María Belén; Mechoso, Roberto; Mohino Harris, Elsa; Castaño-Tierno, Antonio
Although tropical interbasin interactions at interannual time scales are presently receiving much attention, their controlling factors and variations on longer time scales are under debate. Tropical convection plays a crucial role in the occurrence and nonstationarity of them. In this paper, we investigate the dependence of interannual tropical AtlanticPacific basin interactions on convection-related features of the tropical oceans’ climatology, especially the ITCZ position. Wecontrast a CGCM control simulation with an experiment in which tropical convection is modified by an artificial perturbation outside the tropics that reduces the incident shortwave radiation in a region of the South Atlantic. Based on previous work, this modification is expected to shift in latitude the climatological position of the simulated ITCZ. The experiment shows altered Walker circulations, stronger interannual variability over the tropical oceans, a westward extension of the Atlantic Ni˜no pattern and of convection, and shallower thermocline in the Pacific, making the basin more sensitive to both local and remote perturbations. As a consequence, the experiment shows enhanced interannual Atlantic–Pacificbasin interactions at the equator, and weaker teleconnections between the north tropical Atlantic and the equatorial Pacific. The latter seems to occur because the impact of the warm Atlantic SST anomalies is offset by the presence of warm SST anomalies in El Ni˜no region. Despite the uncertainties raised because the simulations are relatively short, we conclude that this work presents a potential explanation for the long-term changes in the tropical basin interactions and offers a novel and useful methodology for their analysis.
Project number: 151
Meteolab como herramienta educativa de Meteorología en el Aula
(2021) Rodríguez De Fonseca, María Belén; Ábalos Álvarez, Marta; Alvarez Solas, Jorge; Ayarzagüena Porras, Blanca; Benito Barca, Samuel; Calvo Fernández, Natalia; de la Cámara Illescas, Alvaro; Durán Montejano, Luis; García Herrena, Ricardo; Garrido Pérez, José Manuel; Gómara Cardalliaguet, Iñigo; Losada Doval, Teresa; Mohino Harris, Elsa; Montoya Redondo, Marisa Luisa; Ordoñez García, Carlos; Polo Sánchez, Irene; Robinson, Alexander James; Sastre Marugán, Mariano; Serrano Mendoza, Encarnación; Yagüe Anguis, Carlos; Zurita Gotor, Pablo; García Burgos, Marina; González Alemán, Juan Jesús; González Barras, Rosa María; González Rouco, Jesús Fidel; Martín Gómez, Verónica; Maqueda Burgos, Gregorio
El Presente proyecto es una continuación de proyectos anteriores dentro de la plataforma de divulgación Meteolab. Meteolab es un proyecto de divulgación de Meteorología y Clima que tiene su origen en 2002, cuando se comenzaron a diseñar experimentos de bajo coste con materiales caseros para la Semana de la Ciencia de la Comunidad de Madrid (CAM). Con los años, se generó un conocimiento que se materializó en 2010 con la concesión de un Proyecto de Innovación Educativa (PIE) financiado por la Universidad Complutense de Madrid (UCM), dirigido por Belén Rodríguez de Fonseca. Gracias a este primer proyecto en el que trabajaron muchos profesores y alumnos de ciencias de la atmósfera, se gestó un portal web (meteolab.fis.ucm.es) en el que los experimentos se explicaban y se grababan para impulsar su difusión. Más adelante, en un segundo proyecto de Innovación Educativa, dirigido por la profesora Maria Luisa Montoya, los contenidos fueron traducidos al inglés. En concreto, los experimentos que componen Meteolab tienen como principal objetivo entender los principios y variables que determinan el comportamiento de las masas de aire en la atmósfera y de agua en el océano. La idea consiste en visualizar con experimentos sencillos las leyes físicas que gobiernan la atmósfera y el océano: movimientos horizontales y verticales, cambios de estado, mezcla y equilibrio, así como la interacción entre componentes. Se persigue observar los procesos meteorológicos familiares, como son la formación de una nube, los tornados, la convección, la formación de borrascas o la lluvia, entendiendo los procesos físicos que los producen. Finalmente, Meteolab permite también visualizar fenómenos climáticos como el efecto invernadero, el fenómeno de El Niño, el deshielo del Ártico, la influencia de los volcanes en el clima o la subida del nivel del mar. Existe un catálogo de experimentos, la mayoría de los cuales pueden consultarse a través del portal meteolab.fis.ucm.es, encontrándose todos ellos físicamente localizados en el Laboratorio Elvira Zurita de la Facultad de Ciencias Físicas. Tras la experiencia acumulada durante los 18 años de existencia de Meteolab, en los que se han adecuado las explicaciones de los experimentos a distintos niveles de dificultad (infantil, primaria, secundaria, bachillerato y Universidad de mayores), se ha sugerido la idoneidad de adaptar los contenidos a los estudiantes del Grado en Física y del Máster en Meteorología y Geofísica de la UCM. Así, por ejemplo, cuando se explica la formación de una nube, se puede ir complicando el discurso dependiendo de los diferentes ciclos de la enseñanza. De esta manera, para un nivel de escuela primaria uno sólo tiene que explicar que el aire se enfría al ascender, y al enfriarse se forman gotas de agua que forman las nubes. Al llegar a secundaria, los estudiantes aprenden el concepto de presión atmosférica y la relación entre la temperatura, la presión y el volumen de una parcela de aire. Más adelante, en el Grado en Física, se estudia la tensión de vapor, la expansión adiabática y la existencia de núcleos de condensación. Finalmente, en el Máster en Meteorología se aprenden los distintos procesos de nucleación y tipos de nubes. Todos estos conceptos van complicando la explicación, por lo que un mismo experimento puede explicarse tanto en una escuela infantil como en una Universidad. Es por ello, que, aprovechando la plataforma de divulgación Meteolab, hemos decidido dar un paso adelante y adaptar y ampliar los contenidos de Meteolab, para así poder integrarlos en los currícula del Grado en Física y del Máster en Meteorología y Geofísica de la UCM. Con todo ello, los objetivos del presente proyecto han sido: -Implementar los experimentos de Meteolab en el Aula, tanto en las asignaturas de Grado como en las de Máster. -Adaptar los contenidos existentes del portal web Meteolab (meteolab.fis.ucm.es) a las asignaturas relacionadas con Meteorología del Grado en Física y del Máster en Meteorología y Geofísica, con el fin de visualizar procesos físicos que se explican en el aula. -Añadir a Meteolab nuevos contenidos en relación con la dinámica de la atmósfera y el cambio climático. -Evaluar la mejora de la comprensión por parte del alumnado de los procesos que tienen lugar principalmente en la atmósfera y el océano, y su relación con el clima y su variabilidad.
Impact of dynamical regionalization on precipitation biases and teleconnections over West Africa
(Climate dynamics, 2018) Gómara Cardalliaguet, Íñigo; Mohino Harris, Elsa; Losada Doval, Teresa; Domínguez, Marta; Suárez Moreno, Roberto; Rodríguez De Fonseca, María Belén
West African societies are highly dependent on the West African Monsoon (WAM). Thus, a correct representation of the WAM in climate models is of paramount importance. In this article, the ability of 8 CMIP5 historical General Circulation Models (GCMs) and 4 CORDEX-Africa Regional Climate Models (RCMs) to characterize the WAM dynamics and variability is assessed for the period July-August-September 1979-2004. Simulations are compared with observations. Uncertainties in RCM performance and lateral boundary conditions are assessed individually. Results show that both GCMs and RCMs have trouble to simulate the northward migration of the Intertropical Convergence Zone in boreal summer. The greatest bias improvements are obtained after regionalization of the most inaccurate GCM simulations. To assess WAM variability, a Maximum Covariance Analysis is performed between Sea Surface Temperature and precipitation anomalies in observations, GCM and RCM simulations. The assessed variability patterns are: El Nio-Southern Oscillation (ENSO); the eastern Mediterranean (MED); and the Atlantic Equatorial Mode (EM). Evidence is given that regionalization of the ENSO-WAM teleconnection does not provide any added value. Unlike GCMs, RCMs are unable to precisely represent the ENSO impact on air subsidence over West Africa. Contrastingly, the simulation of the MED-WAM teleconnection is improved after regionalization. Humidity advection and convergence over the Sahel area are better simulated by RCMs. Finally, no robust conclusions can be determined for the EM-WAM teleconnection, which cannot be isolated for the 1979-2004 period. The novel results in this article will help to select the most appropriate RCM simulations to study WAM teleconnections.
Skillful prediction of tropical Pacific fisheries provided by Atlantic Niños
(Environmental research letters, 2021) Gómara Cardalliaguet, Íñigo; Rodríguez De Fonseca, María Belén; Mohino Harris, Elsa; Losada Doval, Teresa; Polo Sánchez, Irene; Coll, Marta
Tropical Pacific upwelling-dependent ecosystems are the most productive and variable worldwide, mainly due to the influence of El Niño Southern Oscillation (ENSO). ENSO can be forecasted seasons ahead thanks to assorted climate precursors (local-Pacific processes, pantropical interactions). However, due to observational data scarcity, little is known about the importance of these precursors for marine ecosystem prediction. Previous studies based on Earth System Model simulations forced by observed climate have shown that multiyear predictability of tropical Pacific marine primary productivity is possible. With recently released global marine ecosystem simulations forced by historical climate, full examination of tropical Pacific ecosystem predictability is now feasible. By complementing historical fishing records with marine ecosystem model data, we show herein that equatorial Atlantic sea surface temperatures (SSTs) constitute a valuable predictability source for tropical Pacific fisheries, which can be forecasted over large-scale areas up to three years in advance. A detailed physical-biological mechanism is proposed whereby equatorial Atlantic SSTs influence upwelling of nutrient-rich waters in the tropical Pacific, leading to a bottom-up propagation of the climate-related signal across the marine food web. Our results represent historical and near-future climate conditions and provide a useful springboard for implementing a marine ecosystem prediction system in the tropical Pacific.
Revisiting the CMIP5 Thermocline in the Equatorial Pacific and Atlantic Oceans
(Geophysical Research Letters, 2018) Castaño Tierno, Antonio; Mohino Harris, Elsa; Rodríguez De Fonseca, María Belén; Losada Doval, Teresa
The thermocline is defined as the ocean layer for which the vertical thermal gradient is maximum. In the equatorial ocean, observations led to the use of the 20 °C isotherm depth (z20) as an estimate of the thermocline. This study compares z20 against the physical thermocline in the equatorial Atlantic and Pacific Oceans, using Simple Ocean Data Assimilation reanalysis and fifth phase of the Coupled Model Intercomparison Project preindustrial control simulations. Our results show that z20 is systematically deeper and flatter than the thermocline and does not respond correctly to surface wind stress variations. It is also shown that the annual cycle of z20 is much weaker than that of the physical thermocline. This happens in both equatorial basins and indicates that z20 does not react to the same mechanisms as the thermocline. This could have important consequences in the assessment of air-sea coupling in current general circulation models and bias reduction strategies.
The tropical Atlantic observing system
(Frontiers in Marine Science, 2019) Rodríguez De Fonseca, María Belén; Polo Sánchez, Irene; Losada Doval, Teresa; Mohino Harris, Elsa; López Parages, Jorge
The tropical Atlantic is home to multiple coupled climate variations covering a wide range of timescales and impacting societally relevant phenomena such as continental rainfall, Atlantic hurricane activity, oceanic biological productivity, and atmospheric circulation in the equatorial Pacific. The tropical Atlantic also connects the southern and northern branches of the Atlantic meridional overturning circulation and receives freshwater input from some of the world’s largest rivers. To address these diverse, unique, and interconnected research challenges, a rich network of ocean observations has developed, building on the backbone of the Prediction and Research Moored Array in the Tropical Atlantic (PIRATA). This network has evolved naturally over time and out of necessity in order to address the most important outstanding scientific questions and to improve predictions of tropical Atlantic severe weather and global climate variability and change. The tropical Atlantic observing system is motivated by goals to understand and better predict phenomena such as tropical Atlantic interannual to decadal variability and climate change; multidecadal variability and its links to the meridional overturning circulation; air-sea fluxes of CO2 and their implications for the fate of anthropogenic CO2; the Amazon River plume and its interactions with biogeochemistry, vertical mixing, and hurricanes; the highly productive eastern boundary and equatorial upwelling systems; and oceanic oxygen minimum zones, their impacts on biogeochemical cycles and marine ecosystems, and their feedbacks to climate. Past success of the tropical Atlantic observing system is the result of an international commitment to sustained observations and scientific cooperation, a willingness to evolve with changing research and monitoring needs, and a desire to share data openly with the scientific community and operational centers. The observing system must continue to evolve in order to meet an expanding set of research priorities and operational challenges. This paper discusses the tropical Atlantic observing system, including emerging scientific questions that demand sustained ocean observations, the potential for further integration of the observing system, and the requirements for sustaining and enhancing the tropical Atlantic observing system.