21st Century Projections of High Streamflow Events in the UK and Germany

Radiative effects of anthropogenic changes in atmospheric composition are expected to enhance the hydrological cycle leading to more frequent and intense floods. To explore if there will be an increased risk of river flooding in the future, 21st century projections under global warming scenarios of High Streamflow Events (HSEs) for UK and German rivers are carried out, using a model that statistically relates large-scale atmospheric predictors - 850 hPa Geopotential Height (GPH850) and Integrated Water Vapor Transport (IVT) - to the occurrence of HSEs in one or simultaneously in several streamflow gauges. Here, HSE is defined as the streamflow exceeding the 99th percentile of daily flowrate time series measured at streamflow gauges. For the common period 1960-2012, historical data from 57 streamflow gauges in UK and 61 streamflow gauges in Germany, as well as, reanalysis data of GPH850 and IVT fields, bounded from 90W to 70E and from 20N to 80N are used. The link between GPH850 configurations and HSEs, and more precisely, identification of the GPH850 states potentially able to generate HSEs, is performed by a combined Kohonen Networks (Self Organized Map, SOM) and Event Syncronization approach. Complex network and modularity methods are used to cluster streamflow gauges that share common GPH850 configurations. Then a model based on a conditional Poisson distribution, in which the parameter of the Poisson distribution is assumed to be a nonlinear function of GPH850 and IVT, allows for the identification of GPH850 state and threshold of IVT beyond which there is the HSE highest probability. Using that model, projections of 21st century changes in frequency of HSEs occurrence in UK and Germany are estimated using the simulated fields of GPH850 and IVT from selected GCMs belonging to the Coupled Model Inter-comparison Project Phase 5 (CMIP5). Among the different GCMs, those are selected whose retrospective predictor fields have consistent statistics with the corresponding reanalysis data

A Combined Atmospheric Rivers and Geopotential Height Analysis for the Detection of High Streamflow Event Probability Occurrence in UK and Germany

The role of atmospheric rivers (ARs) in inducing High Streamflow Events (HSEs) in Europe has been confirmed by numerous studies. Here, we assume as HSEs the streamflows exceeding the 99th percentile of daily flowrate time series measured at streamflow gauges. Among the indicators of ARs are: the Integrated Water Vapor (IWV) and Integrated Water Vapor Transport (IVT). For both indicators the literature suggests thresholds in order to identify ARs. Furthermore, local thresholds of such indices are used to assess the occurrence of HSEs in a given region. Recent research on ARs still leaves room for open issues: 1) The literature is not unanimous in defining which of the two indicators is better. 2) The selection of the thresholds is based on subjective assessments. 3) The predictability of HSEs at the local scale associated with these indices seems to be weak and to exist only in the winter months. In order to address these issues, we propose an original methodology: (i) to choose between the two indicators which one is the most suitable for HSEs predictions; (ii) to select IWT and/or IVT (IVT/IWV) local thresholds in a more objective way; (iii) to implement an algorithm able to determine whether a IVT/IWV configuration is inducing HSEs, regardless of the season. In pursuing this goal, besides IWV and IVT fields, we introduce as further predictor the geopotential height at 850 hPa (GPH850) field, that implicitly contains information about the pattern of temperature, direction and intensity of the winds. In fact, the introduction of the GPH850 would help to improve the assessment of the occurrence of HSEs throughout the year. It is also plausible to hypothesize, that IVT/IWV local thresholds could vary in dependence of the GPH850 configuration. In this study, we propose a model to statistically relate these predictors, IVT/IWV and GPH850, to the simultaneous occurrence of HSEs in one or more streamflow gauges in UK and Germany. Historical data from 57 streamflow gauges in UK and 61 streamflow gauges in Germany, as well as reanalysis data of the 850 hPa geopotential fields bounded from 90W to 70E and from 20N to 80N are used. The common period is 1960 to 2012. The link between GPH850 and HSEs, and more precisely, the identification of the GPH850 states potentially able to generate HSEs is performed by a combined Kohonen Networks (Self Organized Map, SOM) and Event Syncronization approach. Complex network and modularity methods are used to cluster streamflow gauges that share common GPH850 configurations. Then a model based on a conditional Poisson distribution is carried out, in which the parameter of the Poisson distribution is assumed to be a nonlinear function of GPH850 state and IVT/ IWV. This model allows for the identification of the threshold of IVT/IWV beyond which there is the HSE highest probabilit

Novel stacking models for improved extreme rainfall predictions under climate change scenarios.

Future projections under global warming scenarios of local extreme precipitations by downscaling models is still open challenge. A number of downscaling statistical models have been proposed to link large scale atmospheric circulation features, as simulated by Global Circulation Models (GCMs) and/or Regional Circulation Models (RCMs), to the temporal and spatial distribution of local rainfalls. Despite the efforts, comparisons between simulations and observations show that statistical downscaling methods, although able to realistically reproduce most of the mean rainfall attributes as seasonal or monthly rainfall amount, fail to simulate extreme precipitation with acceptable accuracy. This is due to the difficulties to: (i) select the optimal set of atmospheric variables used as predictors; (ii) solve the non-linear dependencies that link the rains to the atmospheric variables; (iii) assess the temporal dependencies between wet and dry states. To overcome such criticalities, in order to improve extreme precipitation forecasting, in this study we introduce in rainfall downscaling a paradigm already known in other disciplines of data science: the "stacking models". Stacking models combine different simulations from multiple predictive models. According to this approach we used Random Forest, extreme gradient boosting and Non-homogeneous Hidden Markov Model (NHMM). The validation was performed first on the individual models, calibrating the parameters individually and evaluating them globally with a cross validation approach. The performance of the proposed stacking model is assessed by comparing the daily rainfall amount simulations with those obtained by a state-of-the-art NHMM model, in which the probability of the rainfall occurrence is just modeled using a logistic regression with parameters depending upon climatology variables. We show that the stacking model outperforms the latter model, especially in simulating the extreme precipitations. Furthermore, such performance improvement is obtained by using a minor number of atmospheric predictors. Once the downscaling model has been calibrated and validated, we evaluated changes of precipitation extremes under climate change scenarios. The simulations were performed using the variables obtained from a GCM, Community Climate System Model v4 - NCAR, whose scenario is defined by CMIP5 - RCP 8.5. To evaluate the confidence bands of the simulated rainfall it was used an ensemble of simulations obtained by running the latter GCM with different initial conditions. The Lazio region was chosen as a study case. The Lazio Region is located in Central Italy, whose hydrogeological features make it particularly vulnerable to eventual future changes of hydrological cycle such as those induced by climate change. The Mediterranean is made up of many of these vulnerable areas, which makes the application of the method to this case study of general interest

Projecting Changes in Tanzania Rainfall for the 21st century: Scenarios, Downscaling & Analysis

A Non-Homogeneous hidden Markov Model (NHMM) is developed using a 40-years record (1950-1990) of daily rainfall at eleven stations in Tanzania and re-analysis atmospheric fields of Temperature (T) at 1000 hPa, Geo Potential Height (GPH) at 1000 hPa, Meridional Winds (MW) and Zonal Winds (ZW) at 850 hPa, and Zonal Winds at the Equator(ZWE) from 10 to 1000 hPa. The NHMM is then used to predict future rainfall patterns under a global warming scenario (RCP8.5), using predictors from the CMCC-CMS simulations from 1950-2100. The model directly considers seasonality through changes in the driving variables thus addressing the question of how future changes in seasonality of precipitation can be modeled. The future downscaled simulations from NHMM, with predictors derived from the simulations of the CMCC-CMS CGM, in the worst conditions of global warming as simulated by RCP8.5 scenario, indicate that, Tanzania may be subjected to to a reduction of total annual rainfall; this reduction is concentrated in the wet seasons, OND, mainly as a consequence of decreasing of seasonal number of wet days. . Frequency and Intensity of extreme events don’t show any evident trend during the 21 century

Cooperation in school age children: the role of moral identity and family support

openQuesta ricerca si basa sullo studio della cooperazione in bambini in età scolare e del suo sviluppo. Inoltre, abbiamo studiato la relazione che intercorre tra la cooperazione con l’identità morale e il supporto familiare. Per fare ciò abbiamo svolto una ricerca sperimentale su bambini di età compresa tra i sei anni e i dieci anni attraverso l’uso di diversi materiali, tra cui interviste strutturate e dei giochi al computer. Uno di questi era lo Slingshot Challenge, un gioco in cui si segue la regola dei giochi a somma non-zero, ovvero un gioco in cui cooperando si ottengono dei risultati migliori rispetto al non cooperare

Christianisme orthodoxe

La querelle néo-grecque sur la communion fréquente (xviiie siècle) À l’époque byzantine, l’assiduité des fidèles à la communion eucharistique ne semble pas faire l’objet de dissensions, du moins dans l’Église chalcédonienne. Celle-ci se réfère avec constance à l’enseignement de Basile de Césarée (329‑379), qui conçoit l’Eucharistie comme une « nourriture » tout indiquée pour les baptisés (Du Baptême, I, 3, éd. SC 357, Paris 1989, p. 192) et préconise une communion fréquente, même quotidienne ..

Christianisme orthodoxe

La querelle néo-grecque sur la communion fréquente (xviiie siècle) À l’époque byzantine, l’assiduité des fidèles à la communion eucharistique ne semble pas faire l’objet de dissensions, du moins dans l’Église chalcédonienne. Celle-ci se réfère avec constance à l’enseignement de Basile de Césarée (329‑379), qui conçoit l’Eucharistie comme une « nourriture » tout indiquée pour les baptisés (Du Baptême, I, 3, éd. SC 357, Paris 1989, p. 192) et préconise une communion fréquente, même quotidienne ..

Oportunidades, dificultades y capacidades necesarias: Imaginarios sociales de España como destino migratorio en el discurso de la prensa online argentina

The aim is to critically analyze the social imaginaries of Spain as a destination for Argentine migration in the discourse used by two of the country’s main online newspapers. Critical Discourse Analysis premises were applied to 20 journalistic articles published in Clarin.com and LaNacion.com.ar between April 2021 and April 2022 on Argentine migration to Spain. The results show that both reproduce social imaginaries of Spain as a land of opportunities and difficulties, which demands that Argentines have certain skills in order to migrate.El objetivo es analizar críticamente los imaginarios sociales de España como destino de la migración argentina en el discurso de los dos principales medios de prensa online argentinos. Se aplicaron postulados del Análisis Crítico del Discurso a 20 artículos periodísticos publicados en Clarin.com y LaNacion.com.ar entre abril de 2021 y abril de 2022 sobre migración de argentinos/as a España. Los resultados muestran que ambos reproducen imaginarios sociales de España como un lugar de oportunidades y dificultades, que demanda a los/as argentinos/as ciertas capacidades para migrar

Christianisme orthodoxe

En 2009-2010, le séminaire s’est articulé autour de trois thématiques bien distinctes, qui ont chacune occupé un trimestre

Entre la patria y la madre patria: imaginarios de la (in)movilidad a España en la sección de comentarios de «Clarin.com»

La prensa argentina y la española han participado activamente en la historia de movilidades entre ambos países, difundiendo en sus discursos imaginarios sociales favorables a la emigración. Este artículo estudia la recepción de tales mensajes por sus audiencias, indagando en la categoría de imaginarios de la (in)movilidad, que considera tanto la movilidad como la permanencia. Se aplicó un análisis de contenido cualitativo a 310 comentarios de lectores y lectoras en una serie de artículos periodísticos del diario online argentino Clarin.com sobre un eventual asentamiento de argentinos y argentinas en España. Los resultados evidencian una distribución heterogénea de los imaginarios en torno a los ejes inmovilidad-movilidad y origen-destino. Predominan los imaginarios de la movilidad, aunque suelen estar asociados a valoraciones negativas del país de origen más que a evaluaciones positivas del país de destino. Asimismo, se observa un importante componente ideológico y fuertes disputas sobre la idoneidad de España como destino