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CLIVAR Exchanges: Volumen especial sobre el clima en la Península Ibérica
Boundary-Layer Meteorology
As part of the EUropean Cloud REsolving Modelling (EUCREM) model intercomparison project we compa... more As part of the EUropean Cloud REsolving Modelling (EUCREM) model intercomparison project we compared the properties and development of stratocumulus as revealed by actual observations and as derived from two types of models, namely three-dimensional Large Eddy Simulations (LES) and one-dimensional Single Column Models (SCMs). The turbulence, microphysical and radiation properties were obtained from observations made in solid stratocumulus during the third flight of the first 'Lagrangian' experiment of the Atlantic Stratocumulus Transition Experiment (ASTEX). The goal of the intercomparison was to study the turbulence and microphysical properties of a stratocumulus layer with specified initial and boundary conditions. The LES models predict an entrainment velocity which is significantly larger than estimated from observations. Because the observed value contains a large experimental uncertainty no definitive conclusions can be drawn from this. The LES modelled buoyancy flux agrees rather well with the observed values, which indicates that the intensity of the convection is modelled correctly. From LES it was concluded that the inclusion of drizzle had a small influence (about 10%) on the buoyancy flux. All SCMs predict a solid stratocumulus layer with the correct liquid water profile. However, the buoyancy flux profile is poorly represented in these models. From the comparison with observations it is clear that there is considerable uncertainty in the parametrization of drizzle in both SCM and LES.
Unisci Discussion Papers, 2007
Se han utilizado los resultados de 12 AOGCMs (Modelos de Clima Globales) disponibles en la base d... more Se han utilizado los resultados de 12 AOGCMs (Modelos de Clima Globales) disponibles en la base de datos "WCRP CMIP3 multi-model database" para analizar las proyecciones climáticas bajo el escenario de emisiones SRES A2 para el periodo 2011-2040. No hay muchos trabajos enfocados en este periodo, por lo que su estudio es vital para el desarrollo de estrategias a corto y medio plazo como las que requiere el tema de las migraciones. Los resultados obtenidos indican que se proyectan aumentos de temperatura de alrededor de 1ºC en la región del África Subsahariana Occidental. La tendencia para la precipitación es de ligero aumento en la mayoría de las zonas. Estos dos factores implican un ligero aumento de la aridez en las zonas costeras entre Senegal y Camerún, y una disminución en las zonas más interiores. Como consecuencia las proyecciones de disminución de rendimientos agrícolas en la región son dominantes.
ABSTRACT Extreme events of maximum and minimum temperatures are a main hazard for agricultural pr... more ABSTRACT Extreme events of maximum and minimum temperatures are a main hazard for agricultural production in Iberian Peninsula. For this purpose, in this study we analyze projections of their evolution that could be valid for the next decade, represented in this study by the 30-year period 2004-2034 (target period). For this purpose two kinds of data were used in this study: 1) observations from the station network of AEMET (Spanish National Meteorological Agency) for five Spanish locations, and 2) simulated data at a resolution of 50 ×50 km horizontal grid derived from the outputs of twelve Regional Climate Models (RCMs) taken from project ENSEMBLES (van der Linden and Mitchell, 2009), with a bias correction (Dosio and Paruolo, 2011; Dosio et al., 2012) regarding the observational dataset Spain02 (Herrera et al., 2012). To validate the simulated climate, the available period of observations was compared to a baseline period (1964-1994) of simulated climate for all locations. Then, to analyze the changes for the present/very next future, probability of extreme temperature events for 2004-2034 were compared to that of the baseline period. Although only minor changes are expected, small variations in variability may have a significant impact in crop performance. The objective of the work is to evaluate the utility of these short term projections for potential users, as for instance insurance companies. References
Fisica De La Tierra, Jun 15, 2004
En numerosas áreas oceánicas, y particularmente en la zona de los alisios del Océano Atlántico, c... more En numerosas áreas oceánicas, y particularmente en la zona de los alisios del Océano Atlántico, con frecuencia aparecen extensas y persistentes zonas de nubes tipo estratocúmulo. Debido a su gran influencia sobre procesos radiativos, su mejor conocimiento se convierte en un aspecto clave para una correcta descripción del balance radiativo superficial para escalas climáticas. Los modelos de alta resolución tridimensional, conocidos como LES, son una herramienta fundamental para mejorar nuestro conocimiento de estos procesos, y son un primer paso para mejorar las parametrizaciones que los modelos de circulación general, debido a su baja resolución espacial, deben emplear para representar estas nubes. Basado en medidas procedentes de la campaña ASTEX, llevada a cabo en el Océano Atlántico, este trabajo presenta los resultados de una simulación LES de una capa estacionaria de estratocúmulos, analizando detalladamente sus características y los principales procesos físicos involucrados.
Increasing of extreme events is expected under climate change. The impact of such increase will d... more Increasing of extreme events is expected under climate change. The impact of such increase will depend on the vulnerability of the evaluated system. For Mediterranean agricultural systems, extremes temperatures and water deficit are main hazards. The vulnerability of crops and cropping systems varies according to the extreme event considered and timing of crop development. Indexes for extreme events of temperature
Se presenta el análisis de la precipitación diaria sobre la Península Ibérica modelizada por un m... more Se presenta el análisis de la precipitación diaria sobre la Península Ibérica modelizada por un modelo global de clima (GCM) y un modelo regional de clima (RCM) forzado por éste, con dos resoluciones, para clima presente y el escenario A2 de emisiones de gases de invernadero para final del siglo XXI. La estructura espacial básica de la precipitación total anual, con un máximo en el noroeste de la región y un mínimo en el sureste es descrita tanto por el GCM como los RCMs a ambas resoluciones, aunque el GCM no es capaz de mostrar los valores correctos de ambos extremos, ni tampoco diversos aspectos más locales, asociados a la compleja orografía de las cordilleras de la Península, o a efectos costeros. Otro aspecto en el que se obtienen más diferencias es en la estructura espacial del número de días de precipitación. Para condiciones de cambio climático, tanto el GCM como los RCMs muestran un descenso generalizado en la precipitación total y del número de días de lluvia. Palabras clave: Precipitación; regionalización dinámica; cambio climático; modelos regionales de clima.
ABSTRACT The impact of climate variability on the environment and the economic activities mainly ... more ABSTRACT The impact of climate variability on the environment and the economic activities mainly depends on changes in the frequency of occurrence of extreme events. Relatively small changes in the mean can be related to substantial changes in the frequency of extreme events. The objective of this work is to study daily extreme rainfall and temperature events over South America as represented by four regional models and new observational datasets. Within the framework of the EU FP6 project CLARIS, four regional modelling groups have coordinated simulations of South American present climate (1992-2000). The models’ domains cover the entire continent and are driven at the lateral boundaries by ERA40 reanalysis with a horizontal resolution of 50 km. Daily rainfall data used in this study were provided by different national institutions in Argentina, Uruguay, Brazil, Bolivia and Paraguay. The distribution of gauges is relatively homogeneous, except in certain areas in western Argentina and some areas of Brazil and Uruguay. The observational rainfall data are distributed across the La Plata Basin and southern South America regions (70W-40W and 40S-15S). We define a rain day as one on which the rainfall is greater than 0.1 mm and extreme rainfall event is considered when the daily rainfall is greater than the 75th, 90th and 95th daily percentiles threshold. For each subregion selected, the different daily percentiles are calculated on annual and seasonal scales for each meteorological station and for each grid point and model. Due to the nature of climate model, representing the rainfall of an area determined by the model resolution (in this case 50x50km), we expect the percentiles of the station data to be higher than the percentiles of the four models. However, the idea behind this comparison is to verify if the models can capture qualitatively the differences between different regions surrounding the La Plata Basin. The daily temperature data used in this study belongs to an observational gridded dataset with the same resolution as the models that was developed within the framework of the EU FP7 project CLARIS LPB. The daily gridded dataset of surface minimum and maximum temperature covers the region 70W-45W and 40S-20S. For each variable, a warm extreme is considered when the daily temperature is greater than the 75th, 90th, and 95th percentile and a cold extreme when is lower than the 25th, 10th, and 5th percentile. For each grid point, the difference between daily percentiles calculated from model and observational data is computed on a monthly basis. For minimum temperature, all RCMs tend to overestimate warm extremes and underestimate cold extremes. For maximum temperature extremes, results are not so consistent between models. In future studies, the results presented here will be compared with simulation outputs from updated model versions driven by ERA-INTERIM.
The hydrological stresses and specially the dry spells are one of the main climatic features of t... more The hydrological stresses and specially the dry spells are one of the main climatic features of the Mediterranean regions and it can affect and lead to relevant impacts on ecosystems, agriculture and population. It is proposed the analysis of the annual mean dry spells length (DSML) from a group of Regional Climate Model (RCM) simulations of 25km horizontal resolution from ENSEMBLES European project. The capability of these RCMs to reproduce the DSML compared with ECAv6 gridded observational database is first studied in the baseline period (1961-2000). Then percentage change of the DSML from these RCMs forced by different Global Climate Models (GCMs) for future conditions (2021-2050) under A1B emission scenario respect to historical (1951-1980) climate conditions is evaluated. The results show the success of RCMs to reproduce the overall observed dry spells characteristics. A North-to-South gradient of DSML index along the Mediterranean basin is obtained in the baseline and historic...
The objective of this work is to generate and analyse adaptation strategies to cope with impacts ... more The objective of this work is to generate and analyse adaptation strategies to cope with impacts of climate change on cereal cropping systems in Andalusia (Southern Spain) in a semi-arid environment, with focus on extreme events. In Andalusia, located in the South of the Iberian Peninsula, cereals crops may be affected by the increase in average temperatures, the precipitation variability and the possible extreme events. Those impacts may cause a decrease in both water availability and the pollination rate resulting on a decrease in yield and the farmer's profitability. Designing local and regional adaptation strategies to reduce these negative impacts is necessary. This study is focused on irrigated maize on five Andalusia locations. The Andalusia Network of Agricultural Trials (RAEA in Spanish) provided the experimental crop and soil data, and the observed climate data were obtained from the Agroclimatic Information Network of Andalusia and the Spanish National Meteorological ...
International Journal of Climatology, 2014
ABSTRACT It is well known how mountains play a crucial role in the climate system and have very p... more ABSTRACT It is well known how mountains play a crucial role in the climate system and have very particular climate features compared to other regions. Sierra de Guadarrama is a part of the Iberian Peninsula Central System (Spain), a mountain range located in the center of an extensive plateau, dominated by a continental Mediterranean climate but under a strong Atlantic influence. This range provides fresh water to the different settlements in its vicinity, providing enough water resources to several millions of inhabitants, crop fields, industries and the city of Madrid, the capital of Spain. Nevertheless, there is no work studying the role of the synoptic scale in relation to the precipitation in this mountain range. To tackle this problem, this work calculates water vapour flux patterns (WVFPs) using total column water vapour flux as a predictor field due to the close relation between this parameter and the precipitation in mountainous areas. A clustering analysis on the first three principal components of the predictor field was performed and seven differentiated WVFPs were found using a cost function considering local precipitation data for optimum number of cluster determination. Then, an analysis is made for each component in terms of synoptic relation with other fields and well-known broader teleconnection patterns. Finally, an analysis in terms of their contribution to total precipitation, mean rain intensity and probability of precipitation is made. This work is expected to bring new light on the knowledge of precipitation climatology over this crucial and still not very well-known area, and it is a solid step for future precipitation modelling tools validation that combined with reliable measurements will allow to produce realistic precipitation assessments and forecasts in order to improve the hydrological management of this complex area.
CLIVAR Exchanges: Volumen especial sobre el clima en la Península Ibérica
Boundary-Layer Meteorology
As part of the EUropean Cloud REsolving Modelling (EUCREM) model intercomparison project we compa... more As part of the EUropean Cloud REsolving Modelling (EUCREM) model intercomparison project we compared the properties and development of stratocumulus as revealed by actual observations and as derived from two types of models, namely three-dimensional Large Eddy Simulations (LES) and one-dimensional Single Column Models (SCMs). The turbulence, microphysical and radiation properties were obtained from observations made in solid stratocumulus during the third flight of the first 'Lagrangian' experiment of the Atlantic Stratocumulus Transition Experiment (ASTEX). The goal of the intercomparison was to study the turbulence and microphysical properties of a stratocumulus layer with specified initial and boundary conditions. The LES models predict an entrainment velocity which is significantly larger than estimated from observations. Because the observed value contains a large experimental uncertainty no definitive conclusions can be drawn from this. The LES modelled buoyancy flux agrees rather well with the observed values, which indicates that the intensity of the convection is modelled correctly. From LES it was concluded that the inclusion of drizzle had a small influence (about 10%) on the buoyancy flux. All SCMs predict a solid stratocumulus layer with the correct liquid water profile. However, the buoyancy flux profile is poorly represented in these models. From the comparison with observations it is clear that there is considerable uncertainty in the parametrization of drizzle in both SCM and LES.
Unisci Discussion Papers, 2007
Se han utilizado los resultados de 12 AOGCMs (Modelos de Clima Globales) disponibles en la base d... more Se han utilizado los resultados de 12 AOGCMs (Modelos de Clima Globales) disponibles en la base de datos "WCRP CMIP3 multi-model database" para analizar las proyecciones climáticas bajo el escenario de emisiones SRES A2 para el periodo 2011-2040. No hay muchos trabajos enfocados en este periodo, por lo que su estudio es vital para el desarrollo de estrategias a corto y medio plazo como las que requiere el tema de las migraciones. Los resultados obtenidos indican que se proyectan aumentos de temperatura de alrededor de 1ºC en la región del África Subsahariana Occidental. La tendencia para la precipitación es de ligero aumento en la mayoría de las zonas. Estos dos factores implican un ligero aumento de la aridez en las zonas costeras entre Senegal y Camerún, y una disminución en las zonas más interiores. Como consecuencia las proyecciones de disminución de rendimientos agrícolas en la región son dominantes.
ABSTRACT Extreme events of maximum and minimum temperatures are a main hazard for agricultural pr... more ABSTRACT Extreme events of maximum and minimum temperatures are a main hazard for agricultural production in Iberian Peninsula. For this purpose, in this study we analyze projections of their evolution that could be valid for the next decade, represented in this study by the 30-year period 2004-2034 (target period). For this purpose two kinds of data were used in this study: 1) observations from the station network of AEMET (Spanish National Meteorological Agency) for five Spanish locations, and 2) simulated data at a resolution of 50 ×50 km horizontal grid derived from the outputs of twelve Regional Climate Models (RCMs) taken from project ENSEMBLES (van der Linden and Mitchell, 2009), with a bias correction (Dosio and Paruolo, 2011; Dosio et al., 2012) regarding the observational dataset Spain02 (Herrera et al., 2012). To validate the simulated climate, the available period of observations was compared to a baseline period (1964-1994) of simulated climate for all locations. Then, to analyze the changes for the present/very next future, probability of extreme temperature events for 2004-2034 were compared to that of the baseline period. Although only minor changes are expected, small variations in variability may have a significant impact in crop performance. The objective of the work is to evaluate the utility of these short term projections for potential users, as for instance insurance companies. References
Fisica De La Tierra, Jun 15, 2004
En numerosas áreas oceánicas, y particularmente en la zona de los alisios del Océano Atlántico, c... more En numerosas áreas oceánicas, y particularmente en la zona de los alisios del Océano Atlántico, con frecuencia aparecen extensas y persistentes zonas de nubes tipo estratocúmulo. Debido a su gran influencia sobre procesos radiativos, su mejor conocimiento se convierte en un aspecto clave para una correcta descripción del balance radiativo superficial para escalas climáticas. Los modelos de alta resolución tridimensional, conocidos como LES, son una herramienta fundamental para mejorar nuestro conocimiento de estos procesos, y son un primer paso para mejorar las parametrizaciones que los modelos de circulación general, debido a su baja resolución espacial, deben emplear para representar estas nubes. Basado en medidas procedentes de la campaña ASTEX, llevada a cabo en el Océano Atlántico, este trabajo presenta los resultados de una simulación LES de una capa estacionaria de estratocúmulos, analizando detalladamente sus características y los principales procesos físicos involucrados.
Increasing of extreme events is expected under climate change. The impact of such increase will d... more Increasing of extreme events is expected under climate change. The impact of such increase will depend on the vulnerability of the evaluated system. For Mediterranean agricultural systems, extremes temperatures and water deficit are main hazards. The vulnerability of crops and cropping systems varies according to the extreme event considered and timing of crop development. Indexes for extreme events of temperature
Se presenta el análisis de la precipitación diaria sobre la Península Ibérica modelizada por un m... more Se presenta el análisis de la precipitación diaria sobre la Península Ibérica modelizada por un modelo global de clima (GCM) y un modelo regional de clima (RCM) forzado por éste, con dos resoluciones, para clima presente y el escenario A2 de emisiones de gases de invernadero para final del siglo XXI. La estructura espacial básica de la precipitación total anual, con un máximo en el noroeste de la región y un mínimo en el sureste es descrita tanto por el GCM como los RCMs a ambas resoluciones, aunque el GCM no es capaz de mostrar los valores correctos de ambos extremos, ni tampoco diversos aspectos más locales, asociados a la compleja orografía de las cordilleras de la Península, o a efectos costeros. Otro aspecto en el que se obtienen más diferencias es en la estructura espacial del número de días de precipitación. Para condiciones de cambio climático, tanto el GCM como los RCMs muestran un descenso generalizado en la precipitación total y del número de días de lluvia. Palabras clave: Precipitación; regionalización dinámica; cambio climático; modelos regionales de clima.
ABSTRACT The impact of climate variability on the environment and the economic activities mainly ... more ABSTRACT The impact of climate variability on the environment and the economic activities mainly depends on changes in the frequency of occurrence of extreme events. Relatively small changes in the mean can be related to substantial changes in the frequency of extreme events. The objective of this work is to study daily extreme rainfall and temperature events over South America as represented by four regional models and new observational datasets. Within the framework of the EU FP6 project CLARIS, four regional modelling groups have coordinated simulations of South American present climate (1992-2000). The models’ domains cover the entire continent and are driven at the lateral boundaries by ERA40 reanalysis with a horizontal resolution of 50 km. Daily rainfall data used in this study were provided by different national institutions in Argentina, Uruguay, Brazil, Bolivia and Paraguay. The distribution of gauges is relatively homogeneous, except in certain areas in western Argentina and some areas of Brazil and Uruguay. The observational rainfall data are distributed across the La Plata Basin and southern South America regions (70W-40W and 40S-15S). We define a rain day as one on which the rainfall is greater than 0.1 mm and extreme rainfall event is considered when the daily rainfall is greater than the 75th, 90th and 95th daily percentiles threshold. For each subregion selected, the different daily percentiles are calculated on annual and seasonal scales for each meteorological station and for each grid point and model. Due to the nature of climate model, representing the rainfall of an area determined by the model resolution (in this case 50x50km), we expect the percentiles of the station data to be higher than the percentiles of the four models. However, the idea behind this comparison is to verify if the models can capture qualitatively the differences between different regions surrounding the La Plata Basin. The daily temperature data used in this study belongs to an observational gridded dataset with the same resolution as the models that was developed within the framework of the EU FP7 project CLARIS LPB. The daily gridded dataset of surface minimum and maximum temperature covers the region 70W-45W and 40S-20S. For each variable, a warm extreme is considered when the daily temperature is greater than the 75th, 90th, and 95th percentile and a cold extreme when is lower than the 25th, 10th, and 5th percentile. For each grid point, the difference between daily percentiles calculated from model and observational data is computed on a monthly basis. For minimum temperature, all RCMs tend to overestimate warm extremes and underestimate cold extremes. For maximum temperature extremes, results are not so consistent between models. In future studies, the results presented here will be compared with simulation outputs from updated model versions driven by ERA-INTERIM.
The hydrological stresses and specially the dry spells are one of the main climatic features of t... more The hydrological stresses and specially the dry spells are one of the main climatic features of the Mediterranean regions and it can affect and lead to relevant impacts on ecosystems, agriculture and population. It is proposed the analysis of the annual mean dry spells length (DSML) from a group of Regional Climate Model (RCM) simulations of 25km horizontal resolution from ENSEMBLES European project. The capability of these RCMs to reproduce the DSML compared with ECAv6 gridded observational database is first studied in the baseline period (1961-2000). Then percentage change of the DSML from these RCMs forced by different Global Climate Models (GCMs) for future conditions (2021-2050) under A1B emission scenario respect to historical (1951-1980) climate conditions is evaluated. The results show the success of RCMs to reproduce the overall observed dry spells characteristics. A North-to-South gradient of DSML index along the Mediterranean basin is obtained in the baseline and historic...
The objective of this work is to generate and analyse adaptation strategies to cope with impacts ... more The objective of this work is to generate and analyse adaptation strategies to cope with impacts of climate change on cereal cropping systems in Andalusia (Southern Spain) in a semi-arid environment, with focus on extreme events. In Andalusia, located in the South of the Iberian Peninsula, cereals crops may be affected by the increase in average temperatures, the precipitation variability and the possible extreme events. Those impacts may cause a decrease in both water availability and the pollination rate resulting on a decrease in yield and the farmer's profitability. Designing local and regional adaptation strategies to reduce these negative impacts is necessary. This study is focused on irrigated maize on five Andalusia locations. The Andalusia Network of Agricultural Trials (RAEA in Spanish) provided the experimental crop and soil data, and the observed climate data were obtained from the Agroclimatic Information Network of Andalusia and the Spanish National Meteorological ...
International Journal of Climatology, 2014
ABSTRACT It is well known how mountains play a crucial role in the climate system and have very p... more ABSTRACT It is well known how mountains play a crucial role in the climate system and have very particular climate features compared to other regions. Sierra de Guadarrama is a part of the Iberian Peninsula Central System (Spain), a mountain range located in the center of an extensive plateau, dominated by a continental Mediterranean climate but under a strong Atlantic influence. This range provides fresh water to the different settlements in its vicinity, providing enough water resources to several millions of inhabitants, crop fields, industries and the city of Madrid, the capital of Spain. Nevertheless, there is no work studying the role of the synoptic scale in relation to the precipitation in this mountain range. To tackle this problem, this work calculates water vapour flux patterns (WVFPs) using total column water vapour flux as a predictor field due to the close relation between this parameter and the precipitation in mountainous areas. A clustering analysis on the first three principal components of the predictor field was performed and seven differentiated WVFPs were found using a cost function considering local precipitation data for optimum number of cluster determination. Then, an analysis is made for each component in terms of synoptic relation with other fields and well-known broader teleconnection patterns. Finally, an analysis in terms of their contribution to total precipitation, mean rain intensity and probability of precipitation is made. This work is expected to bring new light on the knowledge of precipitation climatology over this crucial and still not very well-known area, and it is a solid step for future precipitation modelling tools validation that combined with reliable measurements will allow to produce realistic precipitation assessments and forecasts in order to improve the hydrological management of this complex area.