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

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Now showing 1 - 10 of 22

Revisiting the CMIP5 Thermocline in the Equatorial Pacific and Atlantic Oceans
(Geophysical Research Letters, 2018) Castaño Tierno, Antonio; Mohino Harris, Elsa; Rodríguez 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.
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.
Project number: 151
Meteolab como herramienta educativa de Meteorología en el Aula
(2021) Rodriguez 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.
Secular Variability of the Upwelling at the Canaries Latitude: An Instrumental Approach
(Journal of geophysical research-oceans, 2022) Gallego, D.; García Herrera, Ricardo; Mohino Harris, Elsa; Losada Doval, Teresa; Rodríguez de Fonseca, María Belén
In this research we make use of historical wind direction observations to assemble an instrumental upwelling intensity index (the so-called Directional Upwelling Index [DUI]) for the coast of Northwest Africa between 26 degrees and 33 degrees N and from 1825 to 2014. The DUI is defined as the persistence of the alongshore winds at the coast and unlike other upwelling indices, it relies on observed wind direction solely, avoiding the suspected bias toward increasing wind speed of historical wind observations documented in previous research. We have found that between June and October, when the upwelling intensity in the area is at its seasonal maximum, the persistence of the north-easterlies measured by the DUI is significantly related to the alongshore wind stress and subsequently with Sea Surface Temperature anomalies at the coast of NW Africa. The analysis of the DUI record does not display a consistent long-term trend but an oscillatory behavior. At interannual time scales this variability can be linked to the changes in the strength and location of the subtropical north Atlantic high-pressure center and at multidecadal scales, the upwelling seems mainly driven by the Atlantic Multidecadal Variability through the modulation exerted by this climatic pattern on the intensity of the Saharan low.
Ocean dynamics shapes the structure and timing of Atlantic Equatorial Modes
(Journal of geophysical research-oceans, 2019) Martín Rey, Marta; Polo Sánchez, Irene; Rodríguez Fonseca, María Belén; Lazar, Alban; Losada Doval, Teresa
A recent study has brought to light the co‐existence of two distinct Atlantic Equatorial Modes during negative phases of the Atlantic Multidecadal Variability: the Atlantic Niño and Horse‐Shoe (HS) mode. Nevertheless, the associated air‐sea interactions for HS mode have not been explored so far and the prevailing dynamic view of the Atlantic Niño has been questioned. Here, using a forced ocean model simulation, we find that for both modes, ocean dynamics is essential to explain the equatorial SST variations, while air‐sea fluxes control the off‐equatorial SST anomalies. Moreover, we demonstrate the key role played by ocean waves in shaping their distinct structure and timing. For the positive phase of both Atlantic Niño and HS, anomalous westerly winds trigger a set of equatorial downwelling Kelvin waves (KW) during spring‐summer. These dKWs deepen the thermocline, favouring the equatorial warming through vertical diffusion and horizontal advection. Remarkably, for the HS, an anomalous north‐equatorial wind stress curl excites an upwelling Rossby wave (RW), which propagates westward and is reflected at the western boundary becoming an equatorial upwelling KW. The uKW propagates to the east, activating the thermocline feedbacks responsible to cool the sea surface during summer months. This RW‐reflected mechanism acts as a negative feedback causing the early termination of the HS mode. Our results provide an improvement in the understanding of the TAV modes and emphasize the importance of ocean wave activity to modulate the equatorial SST variability. These findings could be very useful to improve the prediction of the Equatorial Modes.
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 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 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.
The stationarity of the ENSO teleconnection in european summer rainfall
(Climate dynamics, 2022) Martija-Díez, Maialen; López-Parages, Jorge; Rodríguez Fonseca, María Belén; Losada Doval, Teresa
El Niño-Southern Oscillation (ENSO) influence on European precipitation (Pcp) has been deeply analyzed. Most of the previous studies focus on the atmospheric response in wintertime during the peak of the ENSO episode, showing boreal summer a season with a marginal ENSO signal. Furthermore, the stationarity of the ENSO teleconnection with Europe has not been considered in many works, which could mask possible nonstationary impacts in other seasons like summer. In this research we find a strong influence of eastern Pacific-like ENSO on the leading variability mode of European summer Pcp, showing a dipole-like configuration and linking El Niño with drier(wetter) conditions in northern(southern) Europe. This relationship is not limited to the total cumulative Pcp, but also to the low and extreme Pcp. This impact on European rainfall is found from the 1960s to the 1990s, a 30 years-long period when the position of the extratropical northern jet stream, which acts as a waveguide, favors the teleconnection pathway to Europe. Strikingly, the ENSO events behind this teleconnection reach their peak in summer. However, we show that the resultant Pcp in Europe also depend on the ENSO characteristic of the previous seasons, which could be used for predictability purposes.
Tropical Atlantic mixed layer buoyancy seasonality: atmospheric and oceanic physical processes contributions
(Atmosphere, 2020) Camara, Ibrahima; Mignot, Juliette; Kolodziejczyk, Nicolas; Losada Doval, Teresa; Lazar, Alban
This study investigates the physical processes controlling the mixed layer buoyancy using a regional configuration of an ocean general circulation model. Processes are quantified by using a linearized equation of state, a mixed-layer heat, and a salt budget. Model results correctly reproduce the observed seasonal near-surface density tendencies. The results indicate that the heat flux is located poleward of 10◦ of latitude, which is at least three times greater than the freshwater flux that mainly controls mixed layer buoyancy. During boreal spring-summer of each hemisphere, the freshwater flux partly compensates the heat flux in terms of buoyancy loss while, during the fall-winter, they act together. Under the seasonal march of the Inter-tropical Convergence Zone and in coastal areas affected by the river, the contribution of ocean processes on the upper density becomes important. Along the north Brazilian coast and the Gulf of Guinea, horizontal and vertical processes involving salinity are the main contributors to an upper water change with a contribution of at least twice as much the temperature. At the equator and along the Senegal-Mauritanian coast, vertical processes are the major oceanic contributors. This is mainly due to the vertical gradient of temperature at the mixed layer base in the equator while the salinity one dominates along the Senegal-Mauritania coast.
The Teleconnection of the Tropical Atlantic to Indo-Pacific Sea Surface Temperatures on Inter-Annual to Centennial Time Scales: A Review of Recent Findings
(Atmosphere, 2016) Kucharski, Fred; Parvin, Afroja; Rodríguez de Fonseca, María Belén; Farneti, Riccardo; Martín Rey, Marta; Polo Sánchez, Irene; Mohino Harris, Elsa; Losada Doval, Teresa; Mechoso, Carlos R.
In this paper, the teleconnections from the tropical Atlantic to the Indo-Pacific region from inter-annual to centennial time scales will be reviewed. Identified teleconnections and hypotheses on mechanisms at work are reviewed and further explored in a century-long pacemaker coupled ocean-atmosphere simulation ensemble. There is a substantial impact of the tropical Atlantic on the Pacific region at inter-annual time scales. An Atlantic Nino (Nina) event leads to rising (sinking) motion in the Atlantic region, which is compensated by sinking (rising) motion in the central-western Pacific. The sinking (rising) motion in the central-western Pacific induces easterly (westerly) surface wind anomalies just to the west, which alter the thermocline. These perturbations propagate eastward as upwelling (downwelling) Kelvin-waves, where they increase the probability for a La Nina (El Nino) event. Moreover, tropical North Atlantic sea surface temperature anomalies are also able to lead La Nina/El Nino development. At multidecadal time scales, a positive (negative) Atlantic Multidecadal Oscillation leads to a cooling (warming) of the eastern Pacific and a warming (cooling) of the western Pacific and Indian Ocean regions. The physical mechanism for this impact is similar to that at inter-annual time scales. At centennial time scales, the Atlantic warming induces a substantial reduction of the eastern Pacific warming even under CO_2 increase and to a strong subsurface cooling.