Màster Oficial - Meteorologia

URI permanent per a aquesta col·leccióhttps://hdl.handle.net/2445/2181

Treballs finals del màster de Meteorologia de la Facultat de Física de la Universitat de Barcelona.

Estadístiques

Examinar

Mostrant 1 - 20 de 67

Implementació d’un filtre basat en lògica difusa per a la supressió de línies d’interferència en radars MRR
(2025-10) Armengol Roig, Enric; Bech, Joan; Salcedo Bosch, Andreu
El MRR (Micro Rain Radar) és un radar Doppler apuntat al zenit capaç de determinar l’alçada i la velocitat de caiguda dels hidrometeors mitjançant l’emissió d’ona contínua modulada en freqüència (FM-CW). Un dels primers models de MRR, que porta ja tres dècades de dades observades i encara es troba força estès i operatiu és el MRR-2, desenvolupat per Metek Meteorologische Messtechnik GmbH (Metek). Tot i estar actualment superat per models més avançats, aquest radar segueix proporcionant dades valuoses que justifiquen la recerca i millora en el post-processament de la informació que ofereix. Aquest instrument sovint presenta una sortida alterada amb patrons espuris (línies interferents) d’origen desconegut consistents en nivells de senyal elevats i persistents en el temps que es mostren a certes alçades. La comunitat científica ha dedicat esforços en la supressió d’aquestes línies interferents, atesa l’alteració que comporten en la correcta estimació de les observacions del radar. En aquest Treball Fi de Màster (TFM) s’implementa un filtre proposat recentment, de cancel·lació de línies interferents mitjançant lògica difusa, integrant-lo al software de post-processament RaPROM per a MRR-2 desenvolupat per la Universitat de Barcelona (UB). S’avalua el funcionament d’aquest filtre amb dades de dos radars MRR-2 ubicats a Das i a Puigcerdà, aplicant la configuració original dels autors del filtre, implementada per a radars ubicats a Corea del Sud, i se’n proposen algunes adaptacions.
Estudi dels Valors Extrems de Precipitació: Comparació entre Bases de Dades Interpolades i de Reanàlisi amb Base de Dades Observacionals a la Comarca del Montsià
(2025-10) Pedrazo Martínez, Maria; Llasat Botija, María del Carmen; Marcos Matamoros, Raül
En un context d’escalfament global accelerat, avaluar la fiabilitat dels períodes de retorn de la pre-cipitació extrema és essencial per a una gestió efectiva del risc hidrometeorològic. Aquest estudi examina la capacitat de diferents bases de dades interpolades i de reanàlisi (E-OBS v30.0e, SPAIN02 v2.1/v3.1/v5.0, IBE-RIA01 v1, MOPREDAS i ERA5) per reproduir els valors extrems observats a sis estacions pluviomètriques del Montsià (Terres de l’Ebre) durant el període 1950–2023. La hipòtesi de treball planteja fins a quin punt es conserva el caràcter extrem de la precipitació quan s’utilitzen fonts amb resolució espacial discretitzada, és a dir, si es manté l’extremicitat en el pas del món observacional al món del model. La metodologia es basa en l’anàlisi de màxims anuals (AMS) a resolució diària, el càlcul de la precipitació diària màxima estandarditzada (PME) per homogeneïtzar les diferències entre sèries, i l’ajust de distribucions Generalitzades de Valors Ex-trems (GEV) mitjançant L-moments per estimar quantils associats a períodes de retorn de 10, 20, 50 i 100 anys. Els resultats mostren una bona coherència espacial en la precipitació mitjana, amb màxims concentrats al mas-sís del Parc Natural dels Ports, i evidencien una relació directa entre la resolució espacial de les dades i la intensitat dels valors extrems estimats. No obstant això, algunes bases (com SPAIN02 v3.1 i ERA5) presenten anomalies atribuïbles a processos d’interpolació o al tractament previ dels camps de precipitació. Així mateix, s’identifica una tendència a sobreestimar els extrems associats a períodes de retorn curts (10 anys) i a infraes-timar els corresponents a períodes llargs (50–100 anys), respecte a les dades d’estació, a causa d’un efecte de suavització dels màxims locals
WRF Surface Layer Representation from MODIS and CORINE Land Use Datasets in SE Iberian Peninsula
(2025-07) Pujante Pérez, Alejandro; Udina Sistach, Mireia
Land use representation influences numerical weather models, particularly near the surface, where exchanges of heat and momentum are strongly influenced by terrain parameters. This study focuses on evaluating how different land use datasets—MODIS (MLU) and CORINE (CLC)—affect surface layer representation in the WRF model through its physical schemes and parameterizations. High-resolution simulations were performed over the southeastern Iberian Peninsula, comparing key near-surface variables: land surface temperature, 2-meter air temperature, and 10-meter air wind speed. Model outputs were validated against satellite products and in-situ station observations. Results show that land use determines surface energy fluxes, with CLC generally offering a more realistic representation and better agreement with observations. During daytime 2-meter air temperature seems to be highly influenced by changes in sensible and latent heat fluxes partitioning, while land surface temperature has a greater impact during nighttime
Validating WRF model precipitation phase forecasts using vertical Doppler profilers and disdrometer observations
(2025-07) Calderón de Armengol, Queralt; Bech, Joan
In this work we aim to validate data from two model runs of the Servei Meteorològic de Catalunya’s WRF model post process using the data of three co-located instruments. Theseinstruments are two Micro Rain Radars (MRR2 and MRR-Pro) and a disdrometer (OTT Parsivel 2). Two Fuzzy Verification approaches to resample the data and validate the forecasts were used: one considers the predominant precipitation type during a one-hour interval while the other includes all types which occurred during this period. Contingency Tables were made and Probability of Detection (POD), False Alarm Ratio (FAR) and Gilbert Skill Score (GSS) were used to analyse the model behaviour against lead time and UTC. Results show that the model’s performance depends strongly on lead time and on the method used to resample the data. Tendencies were observed comparing both model runs which are discussed considering the limitations of the study
Examining the Energy Imbalance of Eddy-Covariance Measurements in a Tidal Wetland
(2024-06) Busquets Rubiés, Angèlica; Arias Ortiz, Ariane; Wang, Tianxin; Udina Sistach, Mireia
The energy balance of the Earth’s surface is crucial for understanding biosphere-atmosphere interactions. However, the energy imbalance observed in eddycovariance measurements indicates that our understanding and estimation of ecosystem dynamics remains incomplete. This issue is especially important for wetlands, which have an important role in global climate processes and exhibit the highest imbalances. In this study, we investigated the energy balance closure (EBC) in a restored tidal wetland. The EBC ratio before tidal restoration was 0.9, contrasting with a poor closure of 0.22 after tidal restoration. We applied filters based on friction velocity (u∗), wind direction and zenith angle, as well as accounting for soil heat storage. These filters improved closure before tidal restoration, but did not for the period after tidal restoration. Daily averaged fluxes enhanced closure up to 54%, suggesting the role of water storage, lateral water heat advection and an influence from large-scale eddies. Analysis of the Bowen ratio and the Priestley-Taylor parameter suggests influence of lateral heat advection after tidal restoration. Future research should include the challenging computations of these energy terms. These insights contribute to a deeper understanding of energy exchanges in tidal wetland environments and underlines important terms that should be taken into account, thereby aiding climate change studies and the management of wetland restoration.
Indoor air pollution estimates at a city-wide scale in Barcelona
(2024-07) Julian Izquierdo, Andreu; Marcos Matamoros, Raül; Carnerero Quintero, Cristina; Mateu Armengol, Jan
Urban air quality presents a significant global environmental challenge. In this context, understanding indoor and outdoor air quality levels is key to assessing population exposure better. Despite extensive research on modeling and monitoring air quality, studies that simultaneously model both remain limited. This study addresses this gap by combining Nitrogen Dioxide (NO2) outdoor levels from the CALIOPE-Urban air quality model with indoor-outdoor parametric relations. Bias-corrected NO2 concentration levels at the street scale are used. These NO2 levels are based on a kriging data-fusion method, merging monitoring station data and the CALIOPE-Urban dispersion model. Two parametric relations depending on building use are assessed for deriving indoor air quality levels: infiltration rates and indoor-outdoor ratios. Bias-corrected outdoor levels and the parametric relations are combined to obtain unprecedented city-wide maps containing indoor NO2 concentrations accounting for uncertainty quantification. Despite large confidence intervals in our results, the validation against observational data shows satisfactory model performance. Results reveal significant variations in indoor NO2 concentrations across different districts, with the highest levels observed in areas with heavy traffic such as the l’Eixample district. Specifically, in this area, 70% of homes have a probability of 50% or higher of exceeding the legal threshold of 40 μg/m³, posing considerable health risks for their inhabitants. This comprehensive approach refines the understanding of indoor and outdoor air quality dynamics in Barcelona, revealing NO2 pollution hotspots and enabling reliable and comprehensive air pollution exposure studies.
Verification of precipitation type measurements in an inner valley
(2024-07) Balagué Martínez, Marta; Bech, Joan
This study examines various methodologies for classifying precipitation types at both surface and upper levels in La Cerdanya valley through the implementation of a fuzzy verification framework. By comparing on-site observations from Micro Rain Radars (MRR2, MRR-Pro) with the operational product Rain or Snow (ROS), distinct performances are revealed. At the surface level, ROS displays a high Probability of Detection (POD) for precipitation but also a high False Alarm Ratio (FAR) when compared to MRR2. ROS detects some events that MRR2 misses, which contributes to the high FAR, and is likely due to its ability to identify light and scattered precipitation across the valley while MRRs are only able to detect it above their position. When compared to MRR-Pro, ROS exhibits a lower FAR but also a relatively low POD, suggesting that MRR-Pro captures finer transitional details that ROS is not able to. In terms of surface-type classification, both MRR2 and ROS identify rain and sporadic mixed and snow events evenly, while MRR-Pro observes a wider distribution of all types. Overall, ROS and MRR2 exhibit comparable performance in discriminating precipitation types at surface level within the valley, unlike MRR-Pro. In addition, ROS’s estimates of height profiles using a digital elevation model show consistency with the observations from the MRRs, accurately indicating descending snow levels in several case studies.
The role of gap-filling observational data in air quality data fusion methods: a case study with CALIOPE PM2.5
(2024-06) Barrantes Cepas, Ada; Carnerero Quintero, Cristina; Mateu Armengol, Jan; Udina Sistach, Mireia
Reliable air quality data are vital for informed decision-making, enabling evidence-based mitigation strategies to improve public health and sustainability. Data-fusion methods combining physicsbased air quality models with observational data provide reliable results with full spatial coverage. This study quantifies the impact of imputing missing observational data in these data-fusion methods. We focus on PM2.5 for the Catalonia region during 2019, for which data availability is strongly limited. We first present straightforward gap-filling methodologies, such as linear interpolation and persistence. We then compare these techniques with a state-of-the-art artificial intelligence gapfilling method based on the Gradient Boosting Machine algorithm trained with several years of data (2019, 2021, 2022). To assess gap-filling methodologies, we generate random gaps of varying characteristics identifying the optimal technique for each gap size and availability. Finally, we study how these methods affect the data fusion process applied to the mesoscale air quality model CALIOPE. The PM2.5 output of this system has a horizontal spatial resolution of 1 km x 1 km on a daily scale. The data fusion method uses universal kriging, a geostatistical technique based on a regression model and the spatial correlation between the model and observational data. Data fusion results significantly improve from the raw model estimations, with +24 % and +61 % for the r-value, not using gap-filling of observational data and using it, respectively. Notably, the method’s effectiveness depends on the availability of observations, performing better with GBM-filled data.
Understanding EC-EARTH winter mean precipitation over the tropical Pacific: implications for prediction skill
(2024-06) Burillo Martí, Rubèn; García-Serrano, Javier, 1980-; Sola Salvatierra, Yolanda
This study investigates the seasonal variability of convective precipitation (cPCP) and stratiform precipitation (sPCP) in the tropical Pacific, using hindcasts from the European Community Earth System model (EC-EARTH). Our analysis revealed that cPCP is primarily driven by sea surface temperature (SST), with warmer SSTs leading to increased convective activity. In contrast, thanks to its correlation with SST and also surface solar radiation downwards, results indicate sPCP is more influenced by atmospheric processes. sPCP and cPCP correlation is positive throughout all the tropical Pacific region although, their correlation is negative in the eastern Intertropical Convergence Zone (ITCZ). This region has been studied in detail considering the correlation between the different types of precipitation and the surface latent heat flux (LHF). It has been concluded that in the eastern ITCZ, LHF contributes to increase cPCP rather than sPCP, explaining the negative correlation between them. The study also highlights the limitation of observational data, which usually only provides total precipitation, thereby restraining the ability of the model to predict each precipitation component accurately. Our findings emphasise the possibility for separating precipitation data into cPCP and sPCP to improve model skill by computing the potential predictability of both components
Reanalyses for dense shelf water cascading in the Cap de Creus Canyon and the atmospheric winter conditions
(2023-10) Fos Serdà, Helena; Peña Izquierdo, Jesús; Bladé, Ileana
In the Gulf of Lion (GoL), during cold winters, the local northerly winds cool the continental shelf water, increasing its density until it loses enough buoyancy to sink mainly through the submarine canyon of Cap de Creus. This process is known as shelf water cascading. To assess the interannual variability of the intensity of these events in the past decades, we use the reanalysis dataset Med MFC from the Mediterranean Sea, which has proved to correlate well with in-situ observations of cascading. This also provides a 3D view of the water properties and how they evolve in time. Then, we calculate the sea surface heat and buoyancy fluxes that modify the density of the shelf water using the atmospheric ERA5 and hydrological GloFAS reanalyses. The river freshwater input, the heat loss and the precipitation have been proved to influence the density of shelf water and the intensity of cascading. These fluxes are correlated with the modes of climate variability of the Atlantic Ridge (AR) and Scandinavian Blocking (SCAN): positive phases of AR together with negative phases of SCAN in winter create a larger buoyancy loss on the shelf water in the GoL, and vice versa.
Calibration and future projections of Monte Perdido glacier evolution with the Open Global Glacier Model
(2023-06) Mateos Garcia, Anna; Revuelto Benedí, Jesús; Sola Salvatierra, Yolanda; Santolaria Otín, María
Glaciers are globally retreating due to climate change, and the Pyrenees mountain range is no exception. This study uses the Open Global Glacier Model (OGGM) to explore the dynamics of the Monte Perdido glacier, one of the largest remaining glaciers in the Pyrenees. We explored three calibration approaches to assess their performances when reproducing observed volume decreases. The first approach involved mass balance calibration using terrestrial laser scanning (TLS) data from 2011 to 2022 and climate data from a nearby weather station. The second approach used TLS calibration with default climate data provided by OGGM (GSWP3-W5E5). The third approach used default geodetic mass balance calibration and default climate data. By comparing these calibration strategies and analysing historical data (TLS and ground penetrating radar (GPR)), we obtain insights of the applicability of the OGGM model to this small, mild conditions, Pyrenean glacier. The first calibration approach is identified as the most effective, emphasising the importance of selecting appropriate climate data and calibration methods. Additionally, we conducted future volume projections using an ensemble of General Circulation Models (GCMs) under the RCP2.6 and RCP8.5 scenarios. The results indicate a potential decrease in total ice volume ranging from 91.60% to 95.16% by 2100, depending on the scenario. Overall, this study contributes to the understanding of the Monte Perdido glacier’s behaviour and its response to climate change through the calibration of the OGGM, while also providing the first estimate of its future melting under different emission scenarios.
Intrusions de pols sahariana a la costa mediterrània occidental
(2023-01) Hernández Dominich, Albert; Sola Salvatierra, Yolanda
La costa mediterrània occidental és una zona important per estudiar les propietats òptiques en columna dels aerosols provinents d’Àfrica que alteren la qualitat de l’aire. En el present treball, aquests episodis s’han escollit a partir de l’anàlisi en clústers de les retrotrajectòries del model HYSPLIT a una altura de 3 km. Dels dies seleccionats s’ha analitzat l’espessor òptica dels aerosols (AOD) i l’exponent d’Angström (α) i l’albedo de dispersió simple (SSA) a diferents longituds d’ona a Granada, Burjassot, Barcelona i l’Alta Provença. Les característiques esperables per intrusions de pols mineral s’han apreciat amb més claredat durant l’estiu i la tardor i per les estacions més properes a la regió font. En els episodis més intensos s’observen valors d’AOD elevats i d’α baixos, així com un creixement de l’SSA amb la longitud d’ona. En canvi, l’hivern ha estat l’època de l’any que més ha diferit en aquest comportament a causa de la crema de biomassa per calefacció que genera aerosols de diferents característiques i a les situacions d’estancament típiques durant aquests mesos. Les estacions més allunyades de la regió font també han mostrat valors més diferents degut a la mescla amb altres tipus d’aerosols produïda durant el seu transport a llarga distància. Finalment, no s’han detectat diferències significatives en les propietats de la pols mineral segons la regió d’origen al nord d’Àfrica
Smooth Dynamical Downscaling of the Wind with the Model for Prediction Across Scales (MPAS)
(2022-07) Gil Bardají, Marta; Peixoto, Pedro; Codina, Bernat
In the wind industry, wind time series for the past years are commonly generated using an atmospheric model to dynamically downscale large-scale reanalysis to local wind flow. Instead of relying on a nesting strategy like the Weather Research and Forecasting (WRF) model, the Model for Prediction Across Scales (MPAS) runs on variable resolution meshes that allow for smooth transitions. The goal of this study is to design MPAS meshes that are robust, accurate and computationally efficient for wind resource assessment applications. We have designed a benchmark validation of one-year simulations in wind-energy-relevant locations representing different geographies and flow complexity scenarios. To focus on identifying real differences between modeling wind time series using regional MPAS meshes compared to using WRF nested domains, both models share the same settings whenever possible and the post-processing is analogous for MPAS and WRF output. Besides, WRF simulations were run with and without nudging (the assimilation of reanalysis data on all points of the outer WRF domain), which is an option known to improve the accuracy of the results, and it is not implemented in MPAS yet. The real-data comparison shows that MPAS improves all wind speed metrics with respect to WRF simulations without nudging, but it has generally worse accuracy than the WRF simulations that do have nudging. This is a strong indication that the MPAS model indeed benefits from smooth transitions between scales, and that further developments on MPAS may turn it into a standard for wind resource applications.
Desenvolupament de la climatologia dels medicans
(2022-10) Nebot Roquet, Xènia; Llasat Botija, María del Carmen; Marcos Matamoros, Raül
En determinades circumstàncies atmosfèriques es desenvolupen a la conca del mar Mediterrani uns ciclons que s’assimilen als huracans tropicals, especialment en les seves característiques físiques durant la fase madura, que es denominen “medicans”. Estan associats a forts vents i tempestes, que afecten especialment el sistema costaner i poden causar danys personals i materials. L’objectiu d’aquest treball és desenvolupar una climatologia i analitzar la distribució espacial i temporal d’aquest fenomen. Amb aquest fi s’ha creat un catàleg d’episodis per al període que comprèn des de 1969 fins a l’actualitat, a partir de nombroses referències. A més del catàleg, en aquest estudi també es vol donar a conèixer l’estat de l’art sobre els medicans. Com que les dades meteorològiques aconseguides a partir de la bibliografia són heterogènies, el catàleg s’ha ampliat a partir de les dades de la reanàlisi ERA5. Aquest catàleg ampliat, amb unes dades homogènies, ha estat analitzat i estudiat per caracteritzar-los. Els resultats mostren que tot i no apreciar-se cap cicle interanual ni tendència en els anys estudiats, és un fenomen amb una distribució estacional marcada, amb una gran presència d’esdeveniments a la tardor i un mínim d’activitat a l’estiu. També presenta una distribució espacial heterogènia, de manera que hi ha regions del Mediterrani més susceptibles a patir les conseqüències d’aquest fenomen de temps sever a les seves costes densament poblades
Climatologia i classificació sinòptica de mànegues marines al mar Balear (1989-2021)
(2022-09) Reynés Vega, Jaume; Bech, Joan
L'estudi climàtic de múltiples mànegues marines és una eina necessària per conèixer el comportament d'aquest fenomen i la construcció de bases de dades sòlides amb les quals analitzar-les. Aquest treball tracta l'anàlisi de 712 casos de mànegues en 456 dies al mar Balear, que comprèn la regió limitada aproximadament per les costes de Catalunya, les Illes Balears i el País Valencià, entre els anys 1989 i 2021. En aquest període es fa una anàlisi de la distribució espacial i temporal de les mànegues, les agrupacions d'aquest fenomen en episodis múltiples o outbreaks i les característiques sinòptiques principals en les quals es formen. Els resultats obtinguts demostren que les mànegues marines són comunes a la regió del mar Balear i no obeeixen a factors geogràfics particulars, sinó que hi ha una relació directa amb les àrees densament poblades. De mitjana anual s’observen entre 10 i 12 mànegues a les costes catalanes, entre 7 i 9 mànegues a l'arxipèlag balear i entre 2 i 3 a la costa valenciana. Totes elles es concentren principalment entre el final de l'estiu i la tardor, just quant la temperatura superficial de la mar és màxima i el desenvolupament de fenòmens convectius ja favorable. La classificació sinòptica automàtica de Jenkinson and Collison (1977), modificada per Miró (2017) i Miro et al. (2020), ha demostrat que en les tres regions el tipus sinòptic majoritari en la formació de mànegues és el cicló, seguit de la baixa en superfície o indefinit, el solc, el flux del nord-est, del nord i del sud-oest. A més, s'ha observat com la majoria dels outbreaks de mànegues es varen produir sota les condicions de depressions profundes
Observational and modelling analysis of pollutant concentrations and meteorological factors in Andorra: A thermal inversion case study
(2022-06) Sarasua Etxeberria, Mikel; Udina Sistach, Mireia
The behavior of pollutants in urbanized mountainous areas is complex due to the interactions between the atmosphere and the orography, and frequent thermal inversions inside the valleys can lead to critical contamination episodes that are detrimental to the environment. This work aims to analyze the behavior of pollutants in a complex orography area like the Central Valley of Andorra and to test the interpretability of WRF in an observed persistent thermal inversion case in the area. Anthropogenic impact on primary pollutants like NO2 and PM10 and the higher dependence of the secondary contaminant O3 on meteorological variables are observed. The Random Forest Regression machine learning model shows that thermal inversions have great importance in the levels of pollutants at the bottom of the valley and also that O3 has a high dependence on relative humidity. The WRF model at higher horizontal resolutions is capable of resolving slope and valley winds but can not interpret well the observed thermal inversions. Increased vertical resolution appears to have little effect on outputs and the need for improved model parameterizations formountain areas is highlighted
The impact of radiative forcing on the equatorial stratospheric circulation
(2021) Lacima Nadolnik, Aleksander; Palmeiro Núñez, Froila; García-Serrano, Javier, 1980-
The aim of this work is to evaluate how the Quasi-Biennial Oscillation (QBO), which dominates interannual variability in the tropical stratosphere, responds to diﬀerent radiative forcings in the EC-EARTH climate model version 3.3. Two sets of simulations have been used, consisting in three atmosphere-only and three atmosphere-ocean coupled experiments, which are based on past, present and future conditions. The QBO inﬂuence on the extratropical circulation, formally known as the Holton-Tan eﬀect, has also been assessed during boreal winter (DJF). Results show a notorious shortening of the QBO period and a clear weakening of the QBO amplitude under a warming climate in the coupled simulations; which do not show a signiﬁcant impact on the Holton-Tan eﬀect in the polar vortex.
Weather Radar Rainfall Summer Analysis of Irrigated vs Rainfed Nearby Areas
(2021) Polls i Agell, Francesc; Bech, Joan
The objective of this work is to study rainfall characteristics (frequency, amount and type) in a semi-arid region in the Eastern Ebro basin (Iberian Peninsula). The region is included approximately in a 20 km per 30 km rectangle and is divided in two different areas, one irrigated with an artificial channel, and another one non-irrigated. The two areas may present a big difference of surface temperature in a short distance, particularly during midday hours of summer months due to high evapotranspiration contrasts. The study focusses in finding possible differences in rainfall characteristics between two areas. The methodology used is based on the analysis of radar reflectivity data, which is processed to determine the rainfall type, classified in convective and non-convective, a part of rain occurrence and amount. The work examined June, July and August data from years 2014 to 2020 analysing daily, monthly and total rain events distributions in both areas. The results show a big variability of the rainfall in the region depending on the year and as expected, an increase in convective rain in both areas during the afternoon. Although there is not a significant difference in the rainfall type nor in the convective rainfall rate between areas, there is a difference in the convective rain distribution along each area, being the rain in the irrigated part less homogenous than the non-irrigated part. This study has been performed in the framework of the Analysis of Precipitation Processes in the Eastern Ebro Subbasin project (WISE-PreP, RTI2018-098693-B-C32/AEI).
Skill assessment of a set of retrospective decadal climate predictions with EC-Earth
(2021) Ruiz de Morales Céspedes, Jaume; Palmeiro Núñez, Froila; Bilbao, Roberto; Ortega, Pablo
The climate system is changing with unprecedented consequences for the environment and many socioeconomic sectors. Hence the importance of predicting these changes. This study aims to produce an evaluation of the predictive skill in a decadal prediction system performed with EC-Earth. It speciﬁcally targets three variables of high relevance for human activities, such as sea surface temperature, the sea surface height anomaly (which quantiﬁes sea level rise) and the total cloud cover (which is critical for storm development). The evaluation has mostly focused on two major ocean basins (Paciﬁc and Atlantic), where important modes of variability like the El Ni˜no-Southern Oscillation and the Atlantic Multidecadal Variability take place, and also on the Equatorial stratosphere, where the Quasi-Biennial Oscillation, a highly predictable mode, occurs. Concerning the results, we have shown high prediction skill for all variables in the ﬁrst forecast year. In the following years, we note a general reduction of the predictive skill, particularly in the southeastern Tropical Paciﬁc, which might point to deﬁciencies in the model to simulate ENSO periodicity and/or regionality. Furthermore, a general lack of skill in the North Atlantic, may imply that the Atlantic Multidecadal Variability, at least in EC-Earth, is not a source of sea level predictability. Regarding the QBO, results have shown a high prediction skill, especially in the ﬁrst 29 months. However, the QBO cycle periodicity is not well represented by EC-Earth, which degrades the credibility of the predictions in the subsequent forecast years
Fonts potencials d'ozó troposfèric a Catalunya
(2021) Gili Ciurana, Jordina; Udina Sistach, Mireia
Les altes concentracions d'O3 són freqüentment observades a diverses regions de Catalunya (NE Espanya) i estan relacionades amb la producció i transport de les seves substàncies precursores, provinents majoritàriament de les emissions a l'atmosfera dels sectors del transport i de la indústria. A partir del mètode Concentration Weighted Trajectory (CWT) i de les retrotrajectòries calculades amb el model HYSPLIT, alimentat amb dades del WRF, s'han identificat les principals fonts potencials del territori de Catalunya que contribueixen a elevades concentracions d'O3 a determinats receptors i s'han associat a zones d'alta activitat industrial. Els resultats mostren que les localitzacions de l'interior del territori estan afectades principalment per mecanismes de circulació locals, que transporten la massa d'aire carregada de contaminants emesos per les indústries localitzades al voltant de la zona d'influència del Vallès Oriental, on s'han estudiat les emissions d'una cel·la com a cas particular. Per una altra banda, les emissions de les indússtries no són les principals fonts potencials d'O3 per les localitzacions situades al nord de Catalunya

Examinar

Enviaments recents