bluuebunny/crossref_metadata_2025 huggingface dataset:
Modelling fire-induced meteorological phenomena using the MesoNH/ForeFire model
Authors: Campos Cátia , T. Couto Flavio , Filippi Jean-Baptiste , Baggio Roberta , Salgado Rui
Published: July 2024

Cloud-resolving models coupled to fire propagation models is a powerful tool to understand fire-atmosphere environment. Portugal is one of the countries in Southern Europe with most burned area and numerous ignitions. In 2017, Portugal was affected by several mega-fires with burned areas larger than 10 000 hectares. Some of these fires presented the development of convective clouds, namely pyro-cumulus (pyroCu) and pyro-cumulonimbus (pyroCb). These phenomena can significantly influence the evolution of fire fronts by altering surface winds, increasing burned areas, and accelerating spread rates.  This study aims to study pyro-convection during two mega-fires occurred in 2017. In this study, the Quiaios (October 15) and Pedrogão Grande (June 17) mega-fires are chosen as case studies. It was made 3 numerical simulations with the MesoNH atmospheric model coupled with the ForeFire fire propagation model. The experiments were configured into three nested domains with horizontal resolution of 2000m, 400m and 80m. Two simulations were conducted in one-way mode, with the fire front evolution directly imposed by ForeFire and based on a pre-defined map obtained from official reports. The third experiment, conducted only for Pedrogão Grande, utilized the two-way mode (i.e., fully coupled), allowing for the simulation of the impact of fire-induced atmospheric motions on the fire’s own propagation. The results show the development of pyroCu in Quiaios mega-fire and a pyroCb cloud in the Pedrogão Grande event. In the PyroCb case, the simulations showed the development of intense updrafts, that contributed to the vertical transport of water vapor up to the upper troposphere, allowing cloud formation, which was represented by several hydrometeors’ species inside the plume. The extreme fire environment was also verified in the simulation due to downbursts originating from the pyroCb cloud. This study has provided important insights into the numerical modelling of pyro-convective clouds using Meso-NH/ForeFire simulations. This study was funded by FCT-Foundation for Science and Technology, I.P. under the PyroC.pt project (Ref. PCIF/MPG/0175/2019).
Assessment of wildfire risk due to climate change in the vicinity of the Švihov and Vír water reservoirs in the Czech republic
Authors: Kudláčková Lucie , Poděbradská Markéta , Cienciala Emil , Mašková Radka , Beranová Jana , Novotný Jan , Pikl Miroslav , Bláhová Monika , Zahradníček Pavel , Štěpánek Petr , Žalud Zdeněk , Trnka Miroslav
Published: July 2024

The research focuses on evaluating of changes in fire risk in the vicinity of reservoirs Švihov and Vír in the Czech Republic in the context of rapidly advancing climate change and recent bark beetle calamities. The global interest in fire risk research and management emphasizes its significance in various ecosystems and sensitive locations. Studied areas are suitable for evaluation of potential fire occurrences around the dams, which have far-reaching consequences besides overall ecosystem degradation, pollution, and drinking water shortage, as both reservoirs supply drinking water to 2 million inhabitants, including the capital city.The methodology for predicting fire risk is based on the analysis of historical and current data, modeling, and simulation of fire behavior using modern technologies. Data evaluation identifies changes in vegetation characteristics and fire behavior due to climate change. Fire behavior simulation is currently the most effective scientific research approach for assessing the impact of fire weather on the landscape. The main tool for its identification is the widely used American program FlamMap, which takes into account topography, fuel types, wind speed, and fuel moisture.Climate change alters the composition of forests and agroecosystems, resulting in an increased fire risk in many cases. Higher temperatures and lower humidity increase vegetation flammability, while forest disturbances (such as drought, pests) bring dry fuel and reduce tree resistance to fire. The aim of this study is to assess the change in fire risk due to climate change and bark beetle calamity, which affected the areas of interest in the years 2018–2022. The application of the FlamMap program will provide characteristics of fire behavior and also predict fire risk in the future. This analysis will contribute to the design of prevention strategies and fire protection in water management protected areas, among other things.
The occurrence of bi­oclimatic conditions in Poland – bioclimatic regions and impact of regional baric systems.
Authors: Tomczyk Arkadiusz M. , Bednorz Ewa , Szyga-Pluta Katarzyna
Published: July 2024

The study concerns the determination of the characteristics of bioclimatic conditions, as well as the synoptic situations related to the occurrence of thermal stress conditions, in Poland. The study was based on daily data obtained from the Institute of Meteorology and Water Management – National Research Institute from the period 1966–2020 for 37 synoptic stations in Poland. Based on the obtained data, values of the Universal Thermal Climate Index (UTCI) were calculated. The occurrence of heat stress increases from the north to the south, corresponding with the variability of influx of solar radiation, and is modified by factors at a smaller spatial scale. The results of this paper evidently point to the cooling effect of the waters of the Baltic Sea. In circulation conditions favouring strong and very strong heat stress, e.g. in two of the designated circulation types (T1 and T2), the occurrence of an expansive high-pres­sure ridge in the Atlantic-European area is typical, stretching from the region of the Azores High towards the north-east, with a secondary high developed within its boundaries. In the third of the designated circulation types (T3), the high-pressure area extends from the Azores eastwards, reaching the Black Sea. Each of the three circulation patterns associated with the unfavourable biometeorological conditions of very strong and extreme cold stress in Poland is characterised by strong pressure centres formed in the Euroatlantic region, triggering the airflow from the northern (T4) or eastern (T5, T6) sector. The study revealed high variability of bioclimatic conditions in Poland, both in temporal and spatial terms. The lowest UTCI was recorded in the north-east of Poland and at the east coast of the Baltic Sea. The highest index values were observed in south-western and western regions of the country.  High spatial variability of UTCI related to regional variability of climatic conditions in Poland permitted the designation of bioclimatic regions characterised by the different occurrence of heat stress, particularly in the cool season of the year. Regions in the south-west and west of Poland proved the most favourable in bioclimatic terms, with the highest number of days with no thermal stress. In these regions, the highest UTCI values were observed, while the lowest were recorded in the northeast of Poland and at the east coast of the Baltic Sea. Among unfavourable biometeorological conditions, the ones causing hypothermia have so far occurred more frequently than the ones causing overheating of the human organism.
Developing outdoor comfort prediction models and their applications based on long-term climate data. 
Authors: Lin Tzu-Ping , Wu Yi-Chen
Published: July 2024

This study aims to explore how to utilize RayMan to generate simplified thermal comfort index assessment formulas, leveraging solar radiation data exported from simulation software, and to achieve simplified evaluation and application of thermal comfort index maps at different scales.
Through comparing data from relevant journals, meteorological agencies, and software-exported solar radiation data, it was found that the solar radiation values from Insight and ARGIS are reasonably accurate. At the site scale simulation, Insight was chosen, providing data in a grid format where each point represents the radiation conditions within one square meter. It also presents values reduced due to shading, which can be considered as corrected Sky View Factor data. Therefore, the influence of Sky View Factor on thermal comfort need not be further considered in subsequent research.
For urban scale analysis, ARGIS was employed, capable of producing data including direct radiation, diffuse radiation, and their combination. RayMan attempted to decompose the regression formulas of Tmrt and PET using extensive data, yielding significantly high R-squared values and significance. Among the variables, temperature, solar radiation, and wind speed were included.
The research results demonstrate that with these three variables, outdoor thermal comfort can be rapidly assessed, with higher accuracy particularly when radiation values exceed 600 (W/m²). Solar radiation data obtained through simulation software can be converted into thermal comfort indices using simple formulas. Ultimately, it is anticipated to utilize other visualization tools such as Dynamo and GIS to visualize thermal comfort indices as grid maps, aiding architects in identifying outdoor thermal discomfort spots on sites and implementing corresponding design improvements.
Filling gaps in urban temperature observations by debiasing ERA5 reanalysis data
Authors: Jacobs Amber , Top Sara , Vergauwen Thomas , Caluwaerts Steven
Published: July 2024

Gaps in urban meteorological time series are a widely known phenomenon, occurring in all sorts of urban datasets, ranging from crowd-sourced data till urban climate networks. These gaps cause a problem, since they complicate the analysis and further use of the dataset. Various gap-filling techniques exist to tackle gaps in meteorological time series, including the debiasing of ERA5 reanalysis data. Unfortunately, the evaluation of these ERA5 debiasing techniques are often performed separately and limited to rural locations. Since the ERA5 bias is highly pronounced for urban locations, a good understanding of the performances of the debiasing techniques with respect to urban data is crucial to obtain accurate gap-filling estimates. To gain a better insight into the most optimal gap-filling techniques for urban temperature time series, we compared five techniques, including three different debiasing techniques that employ a learning period and time window to take into account the seasonal and diurnal characteristics of the ERA5 temperature bias. The evaluation, which is performed by filling manually constructed gaps, shows that small gaps are ideally filled by linear interpolation, while for larger gaps the best performance is obtained through the ERA5 debiasing techniques. For urban locations, the results indicate that it is crucial to correct for the ERA5 bias. We also investigated the most optimal length and placement of the learning period and time window, although the settings of these parameters do not seem to have a significant impact on the gap-filling performance. Based on these results, we designed a gap-filling algorithm that efficiently fills a series of gaps in urban temperature time series by selecting the most optimal gap-filling procedure for each gap. This newly designed algorithm is able to successfully reproduce the urban heat island effect, although a small over- or underestimation might occur.
In-situ measurements of Saharan dust concentrations and charge over Cyprus with an uncrewed aircraft system
Authors: Savvakis Vasileios , Schön Martin , Bramati Matteo , Bange Jens , Platis Andreas
Published: July 2024

Mineral dust is one of the biggest contributors of particulate matter in the atmosphere, and its transport as well as atmospheric implications has been a topic of interest for the last few decades. Still, mineral dust dynamics are often not appropriately accommodated in model simulations, which require in-situ datasets for more accurate representation of dust events. In our study, the uncrewed aircraft system (UAS) of type MASC-3 was employed for measurements of meteorological parameters (potential temperature, mixing ratio and the three-dimensional wind vector at high temporal resolution), turbulent quantities, aerosol particles and space charge, during an intense dust event over Cyprus in spring, 2022. Vertical profiles up to 3000 m above sea level (a.s.l) revealed how the dust layer had peaks at 1800 and 2500 m, as well as affected the extent of the atmospheric boundary layer. The measurements from the UAS were in good agreement with remote sensing instrumentation in the vicinity of the flights, with the observations being further supported by satellite imagery and back tracking model simulations. Vertical profiles of charge were also co-related to approximated modeled one-dimensional profiles of the expected charge for the given dust concentrations. The results showed several layers of charge throughout the dust cloud’s vertical extent, most notably at its upper and lower boundaries, as anticipated from theoretical calculations. This is the first time charge measurements were made possible using a UAS, and in combination with data for dust concentrations and meteorological quantities, new insights can be discovered regarding mineral dust charge, characteristics and its interaction with the atmosphere.
Numerical weather forecasts supporting the Renewable Energy Sector (RES) in Poland
Authors: Wieczorek Joanna , Bochenek Bogdan , Jurasz Jakub , Figurski Mariusz , Jaczewski Adam , Gruszczynska Marta , Mazur Andrzej , Strzyzewski Tomasz
Published: July 2024

The climate and energy crises are going hand in hand. The need to adapt to the excess heat and the energy demand - especially for cooling - will increase. The biggest relative change in Cooling Degrees Days will particularly affect the population of Central and Northern Europe. Thus, a good plan is needed to organise the energy system, preferably designing the use of RES resources as adopted by the European Commission in the 'fit for 55' package. Poland's gross domestic consumption still falls short of achieving a 20% share of green energy in the energy mix. The share of RES in domestic production is steadily increasing, especially in the prosumer installations segment. Due to local problems with energy connections and storage, one of the key issues remains maximising self-consumption from in-house installations. On an annual basis, it can be approximated that wind turbines will operate at rated capacity for an average of 25% of hours per year, and photovoltaic installations will average about 12% of hours per year. However, the expected energy yields can be realistically assessed only by taking into account the synoptic variability of cloud cover, irradiation, and airflow conditions. As well as their variation in neighbouring locations or on consecutive dates for the same location. In October 2023, the - first in this part of Europe – public free-of-charge RES forecast service for micro-installations in Poland was launched. Constant and averaged solar irradiance values and wind speed generated from the ECMWF HRES 0.1° model fields were assumed in hourly intervals. The forecast values were expressed as a percentage [%] of the rated power yield of a wind or photovoltaic installation according to the assumed installation parameters: a wind turbine with a diameter of 1 m2, an installed rated capacity of 8.2 kW, and a threshold value of useful wind speed of 3 ms-1. As a model, the photovoltaic installation was one PV module of southern exposure, the slope of the unit 30% from the ground, and the power generated under standard conditions of 1 kW, where the maximum daily intensity of solar radiation under standard conditions was set at 1000 Wm-2. The module operating temperature under real conditions was set at 50°C, and the overall system efficiency, considering losses on the inverter, cabling, or module dirt, was set at 80%.
Temperature indices in Norway
Authors: Tajet Helga Therese Tilley , Hanssen-Bauer Inger , Gangstø Reidun , Verpe Dyrrdal Anita , Brox Nilsen Irene , Tveito Ole Einar , Dobler Andreas , Hygen Hans Olav
Published: July 2024

The temperature is increasing historically and is projected to rise in future scenarios. This trend is evident both globally and locally in Norway. In Norway, the temperature has increased by about 1.3 degrees Celsius since 1900 and is expected to continue increasing in the future.  Changing temperature, and the impacts on various climate indices, are affecting all parts of the society. Here different temperature indices are studied. Changing temperature affects, among other things, infrastructure, such as roads and buildings. This leads to changes in for instance design values, which again affects the requirements for buildings, such as insulation, cooling and heating.  To study temperature indices, observation based and bias-adjusted daily climate projections with a 1km grid resolution that covers mainland Norway are used. For the two historical normal periods 1961-1990 and 1991-2020, and for the future climate in the periods 2041-2070 and 2071-2100, for three scenarios RCP2.6, RCP4.5 and SSP3-7.0.  The result shows for example fewer days with freezing temperatures and more summer days in Norway. Other temperature indices that are studied are climatological seasons, growing season, heat waves, tropical days and days with zero crossings. Mainland Norway stretches from about 58 °N to 71 °N, has a long coastline in the west, high mountains and steep valleys, this leads to huge variations throughout the country and seasons. This affects the temperature indices and are clearly visible in the maps. The Norwegian Centre for Climate Services (NCCS) provides information for climate adaptation and helps municipalities to be robust in a changing climate. Information about changes in temperature indices can be of help and background information for climate adaptation. All authors in this abstract are connected to NCCS.
Evaluation of IMERG V6 and V7 satellite precipitation and their application on lifetime prediction of wind turbine blades 
Authors: Dimitriadou Krystallia , Hannesdóttir Ásta , Cantero Nouqueret Elena , Hasager Charlotte Bay
Published: July 2024

Accurate precipitation estimation is crucial for various meteorological and climatological applications, including renewable energy generation. The NASA Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (IMERG) product provides precipitation data derived from microwave and infrared satellite sensors. In this study, we evaluate the performance of two successive versions, V6 and V7, of the IMERG Final Precipitation Satellite Product. The evaluation of IMERG V6 and V7 products involves comparing rainfall time series of 6 years (2015-2020) against rain gauge measurements from 28 weather stations in complex terrain in Navarra, Spain. We assess various statistical metrics such as correlation coefficient, bias, root mean square error, and probability of detection. We hypothesize that the V7 product displays improvements from the V6, particularly in terms of accuracy. The objective is to assess if the V7 product demonstrates enhanced performance in capturing precipitation events in a region with complex terrain, such as Navarra. We aim to provide evaluation results and valuable insights for users relying on IMERG precipitation data for hydrological, meteorological, and climate studies.  We also investigate the utility of IMERG precipitation products in the context of wind energy applications. Precipitation, including rain and hail, can impact the structural integrity and performance of wind turbines over time. Surface erosion of wind turbine blades is caused by heavy precipitation and strong winds and represents a major challenge in the wind energy industry. Therefore, we focus on predicting the lifetime of wind turbine blades in the 28 stations by integrating IMERG precipitation in an erosion onset prediction model along with New European Wind Atlas (NEWA) wind speeds. Previous studies that have used IMERG V6 in a blade lifetime prediction model have shown that IMERG V6 is sufficient to predict erosion onset time in blades in selected European sites, but it requires further calibration and adjustments since it tends to overestimate orographic rainfall. We hereby explore any improvements in the prediction of erosion onset time by incorporating the newly published IMERG V7 product. Finally, we aim to highlight the usefulness of satellite data in monitoring leading-edge erosion in wind turbine blades.The proposed approach holds promise for improving the reliability and efficiency of wind turbines. The knowledge of erosion onset time in blades can optimize maintenance schedules, reduce downtime, and enhance the overall operational performance of wind farms. Our findings may offer valuable implications for the renewable energy sector and precipitation monitoring.This work is supported by the AIRE project, which has received funding from the European Union under the grant agreement 101083716.
Reconstruction of floods in Poland in the last 1000 years
Authors: Ghazi Babak , Przybylak Rajmund , Oliński Piotr , Pospieszyńska Aleksandra
Published: July 2024

The reconstruction of floods in Poland in the last millennium (11th–20th centuries) was evaluated based on more than 1,300 weather notes and sources describing floods. After assessing the quality of each source, the most reliable sources were used for the investigation of flood occurrences. The most commonly used methods for the classification of flood intensity in Europe (Barriendos and Coeur 2004; Brázdil et al. 2006) have been used. The genesis of floods was estimated based on the method presented by Lambor (1954). The results demonstrated that more than 1,600 floods occurred in Poland in the last millennium. The highest number of floods occurred in the 18th (356) and 16th (345) centuries, while the lowest occurred in the 19th (187) and 11th–15th (210) centuries. Assessment of flood trend analysis based on the Mann–Kendall test showed that from 1301 to 2000 there was an increasing trend in the frequency of floods. Analysing the spatial diversity of floods in Poland in the study period indicated that the highest number of floods occurred in the Oder River basin. Also, the number of floods in the Silesia and Baltic Coast regions was significantly more than in the other four analysed regions. The estimation of the intensity of floods demonstrated that most of the floods belong to the “above-average, or supra-regional flood” and the “extraordinary” categories according to Brázdil et al. (2006) and Barriendos and Coeur (2004) classifications, respectively. The evaluation of the main genesis of floods indicated that rain and its sub-types (torrential, frontal, long-lasting, territorially widespread) were the main cause of floods in Poland in the 11th–20th centuries. Studying floods in Poland before the 21st century will improve our understanding of historical hydrology in Europe.The work was supported by the National Science Centre, Poland, project No. 2020/37/B/ST10/00710.References:Barriendos, M., Coeur, D, 2004: Flood data reconstruction in historical times from non-instrumental sources in Spain and France. Systematic, Palaeoflood and Historical Data for the Improvement of Flood Risk Estimation. Methodological Guidelines, edited by: Benito, G. and Thorndycraft, VR, Centro de Ciencias Medioambientales, Madrid, Spain, pp. 29–42.Brázdil, R., Kundzewicz, Z. W., & Benito, G., 2006: Historical hydrology for studying flood risk in Europe. Hydrological sciences journal, 51(5), 739–764. https://doi.org/10.1623/hysj.51.5.739.Lambor, J., 1954: Klasyfikacja typów powodzi i ich przewidywanie. Gospodarka Wodna, 4, 129–13
Exploring outer-loop land-atmosphere coupling
Authors: Herbert Christoph , Weston Peter , de Rosnay Patricia , Fairbairn David , Pinnington Ewan
Published: July 2024

The land-atmosphere coupling approach in current state-of-the-art NWP systems is based on weakly coupled data assimilation systems for individual Earth-system components. Atmospheric and land surface analyses are performed separately, and results are fed back into the next data assimilation window based on a model forecast. This can lead to imbalanced initial conditions or shocks and the observations cannot be fully harnessed for all components when assimilated only into one Earth system component within the same window.The CopERnIcus climate change Service Evolution (CERISE) project aims to advance coupled surface-atmosphere assimilation in the preparation of the next generations global and regional reanalysis systems. As for the land, ECMWF’s activities are towards a unified Land Data Assimilation System (LDAS) based on the Simplified Extended Kalman Filter (SEKF) that incorporates multi-layer soil moisture analysis in operations and is currently being extended to other variables, making it suitable for improved coupling.As part of CERISE, a “quasi-strongly coupled data assimilation” is being developed based on "outer land-atmosphere coupling" approach. Aim is to activate the SEKF as part of several 4D-Var outer loops and return the updated land analyses to initialize the atmosphere and the land of next outer loops within the same assimilation window. Initial efforts have focused on infrastructure developments to enable running the SEKF within the 4D-Var non-linear trajectory.This work presents the preliminary results of scientific activities, numerical experimentation, and preliminary results to identify the proper number of outer loops required for optimal coupled land-atmosphere assimilation by testing different coupling configurations. For variables that are subject to strong diurnal cycles – such as soil and skin temperature - balanced initial conditions between the different outer loops can be advantageous. The new infrastructure has the capability to improve the exploitation of interface observations (e.g. land surface temperature) so that they can simultaneously influence the analysis of multiple Earth system components.
Quasi-Biennial Oscillation teleconnection to El Niño variability
Authors: Rodrigo Mario , García-Serrano Javier , Bladé Ileana
Published: July 2024

The Quasi-Biennial Oscillation (QBO) of equatorial zonal winds is the leading mode of lower-stratospheric variability. Numerous studies have explored its connection with the troposphere, including its sensitivity to tropical convection and the El Niño-Southern Oscillation (ENSO). In particular, the upward ENSO impact on the QBO is known: observational evidence suggests that during El Niño the QBO propagates faster (shorter period). However, the potential downward QBO influence on ENSO has not been thoroughly assessed and needs better understanding. Here, we focus on the strongest ENSO events, dubbed super El Niños, characterized by extreme sea surface temperature (SST) anomalies in the eastern Pacific. Super El Niños are exceptional due to self-limiting ENSO dynamics in the tropical Pacific and seasonal SST cooling during summer and autumn, which prevents strong eastern Pacific SST warming and convective anomalies from developing. Their existence requires one or more factors external to the tropical Pacific to aid the Bjerknes feedback in building an El Niño event. In both observations and models (EC-EARTH), super El Niño events seem to require the westerly QBO phase to coincide with a growing El Niño, i.e. in boreal summer and fall. We thus propose a novel element that contributes to the generation of extreme El Niño events that involve the QBO and its modulation of the Walker circulation. While an El Niño event typically leads to a weaker Walker circulation, the weakening becomes more pronounced if the QBO is in its westerly phase. Consequently, the low-level trade wind anomalies over the equatorial Pacific are intensified, which reinforces the Bjerknes feedback and enhances the warm anomalies over the cold tongue region. Our results suggest that the QBO state could be considered to improve El Niño predictions, especially for extreme events.
Dry and wet spells variability in Poland in the period 1966-2023
Authors: Wibig Joanna
Published: July 2024

The aim of this study is to present the spatial and temporal variability of the frequency of dry and wet days and dry and wet spells against the background of changes in precipitation and atmospheric circulation. The study is based on daily precipitation totals from 46 meteorological stations in Poland for the years 1966-2023. Additionally seven circulation indices were used: GBI, NAO, AO, EA, EA/WR. SCAND ana AMO. Dry days are defined as days without precipitation. Wet days are days with at least 1 mm of precipitation. It was shown that dry spells are much more common that wet spells, are longer and cover larger areas. Long term changes in annual characteristics of dry and wet days and spells are statistically insignificant. Only the length of the longest dry spell in the year increases. However, there are significant changes in their annual cycles. Spring is drier, especially April in summer months, precipitation decreases in the south and increases in the north, the same concerns dry day frequencies, November and December, symbols of gloomy rainy weather, are increasingly drier, rainy weather moved to January and February. Preliminary analysis of the impact of atmospheric circulation on the occurrence of dry and wet spells indicates high seasonal variability. In cold season, the Scandinavian type has the greatest influence, the presence of high pressure system over Scandinavia favors dry weather. In summer, precipitation and dry and wet spell occurrence are influenced by the NAO, AO, type EA and presence of high pressure system over Greenland. In spring and autumn, EA/WR type influences can be noticed.This research was funded by National Science Center (NCN), grant number 2019/33/B/ST10/0113
Exploring the use of automatic weather stations for climate monitoring: The Basque Country case study
Authors: Hernandez Roberto , Iza Maddalen , Martija Maialen , Gaztelumendi Santiago , Aranda José Antonio
Published: July 2024

Effective climatic studies and climate monitoring rely heavily on access to extensive, high-resolution, and long-term instrumental climate data. However, our ability to comprehend, detect, predict, and address climate variability and change at finer spatial scales than global ones is currently hindered by the limited availability and accessibility of long-term, high-quality climate records and datasets. In this context, it is important to note the ongoing transition from manual observation networks to automatic systems, with fully automatic observation networks predominating in much of Europe, including the Basque Country.In this contribution, we present some actions taken with the aim of establishing under what conditions and circumstances automatic stations deployed throughout our territory can be used in the context of climate monitoring. Particularly, we focus on the automatic measurement network operated by the Basque Meteorological Agency (Euskalmet), which currently consists of approximately 130 automatic weather stations (AWS) delivering real-time data on different variables across the territory at 10-minute intervals. While the network is primarily oriented towards real-time surveillance of severe weather events, including flooding, measurements are far from ideal from the climatic perspective.Nevertheless, some stations have been operational since the early 1990s, providing relatively long data series spanning 20-30 years at various locations, potentially offering valuable local climate data. However, it is well known that many factors affects usability and value of such data not only the length of data availability or quality but also its overall representativeness, which may be compromised by environmental conditions at specific locationsOur final goal is to provide insights regarding the use of AWS data from the analyzed network for climate monitoring at local scale. To achieve this, we identify stations closest to WMO climate observation criteria, select those with the best data quality characteristics possible, implement procedures for constructing essential climatic data series, including data curation and homogenization, generate derived climatic indicators for anomaly and trend comparison purposes, and conduct validation studies to draw conclusions.
The vulnerability of the small mediterranean village of Alcanar to floods: hasincreased the impact or the number of cases in the last years?
Authors: Rigo Tomeu , Llasat Carme , Marcos Raül , Pascual Ramon
Published: July 2024

The Montsià county is the southernmost region of Catalonia (NE Spain), located between the final stretches of the Ebro River and the Sénia River. It is crossed by a relatively high mountain north-south oriented range (Serra del Montsià, 764 m.a.s.l). This range runs very close and parallel to the coastline. Numerous steep torrents originate in these mountains and traverse densely populated areas (particularly in the summer months). This affects mainly tourist and summer resorts, producing a heightened vulnerability to flooding. The municipality of Alcanar is a clear example of this situation. Between 1980 and 2020, Montsià County recorded 42 flood events, with 21 causing significant damage in Alcanar. These flooding events are typically triggered by very convective and high-intensity local and sudden rainfall, making accurate predictions challenging. The recent flood events of October 2018 and September 2021 and 2023 are good examples of such situations.In this framework, our research seeks to fulfill two main objectives. The first one is to perform the meteorological analysis of the former three events  (2018, 2021 and 2023). This part has consisted of the characterization of the synoptic environment and the role of the mesoscale in the lightning and precipitation patterns. Data from radar, lightning detection systems, and rain gauges have helped to reach this point. The events display high variability in several factors such as the electrical activity, cloud vertical development, the affected regions, and the precipitation field. Hence, they represent a complex analysis that might lead to better understand processes that could affect most of the Mediterranean basin, as well as other regions around the globe. The second goal has been the characterization of the frequency and possible temporal trends of heavy rainfall events using daily and sub-daily precipitation data. 
Long term university-administration collaboration for assessing solar radiation resource in Catalonia
Authors: Calbó Josep , González Josep-Abel , Enríquez-Alonso Aarón , Baldasano José M. , Esteve Joan , Rotllan Marc
Published: July 2024

The Catalan Institute for Energy (ICAEN) is a public corporation of the Government of Catalonia whose mission, since 1991, is the promotion of energy efficiency and renewable energies, the elaboration of energy planning and policies of Catalonia, and the compilation of energy statistics. In particular, and with regard to solar energy, ICAEN established a solar radiation measurement network across the country and has kept it in operation until the present. This network includes 10 stations devoted to the measurement of global and diffuse radiation. Based on the data collected, which is made available on demand to interested users, two versions of Solar Radiation Atlas in Catalonia have been prepared in the past (1995, 2000). The maintenance of the stations, the updating of instruments and data loggers, and the processing of the data has been performed, over time, with the collaboration of academic institutions: the Universitat Politècnica de Catalunya, between 1990 and 2021; and the Universitat de Girona, from 2022 to the present. Researchers from these universities have provided their expertise in solar radiation and climatology. In addition, several selfless collaborators have taken care of each station. Currently, traditional Kipp&Zonen CM11 pyranometers (or similar models), one of which in each site is installed with a sun band for the measurement of diffuse radiation, are being replaced by DeltaLink SPN1 instruments that simultaneously measure global and diffuse radiation and upload the data, in real time via the internet, on a central server. All historical data are currently being reanalyzed with stricter quality control and a new Atlas of solar radiation in Catalonia is being drawn up. In summary, this long-term collaboration between university and administration is an example of success, resulting in very long (over 30 years in some cases) solar radiation data sets of high quality and with notable spatial density (1 station every 3000 square km approximately).
Improving urban design to address human thermal discomfort in urban agglomerations characterized by different microclimatic conditions
Authors: Nastos Panagiotis T. , Polychroni Iliana , Nastou Marina-Panagiota P. , Charalampopoulos Ioannis , Solomos Stavros , Zerefos Stelios
Published: July 2024

The Urban Heat Island (UHI) phenomenon has become a significant concern in urban areas worldwide as urbanization continues to intensify. This process leads to notable changes in microclimates within cities, resulting in higher temperatures compared to their surrounding rural areas. Referred to as the Urban Heat Island effect, this phenomenon is mainly caused by human activities such as industrialization, transportation, and construction, which alter land surfaces and increase heat retention.Identifying hot spots within cities necessitates a thorough understanding of various contributing factors, including land use patterns, building density, surface materials, and the distribution of green spaces. ENVImet modeling facilitates this understanding by allowing precise simulation of microclimates, enabling researchers and planners to pinpoint areas with elevated temperatures and analyze their underlying causes. Once hot spots are identified, ENVImet plays a crucial role in devising optimized mitigation scenarios. By simulating interventions like increasing green space coverage, implementing cool roofs and pavements, optimizing urban layouts for improved airflow, and integrating water bodies, ENVImet enables stakeholders to assess the effectiveness of each strategy in reducing temperatures and mitigating UHI effects.The objective of this study is to optimize the urban design of established infrastructure within cities experiencing different microclimatic conditions, such as Aspropyrgos in the greater Athens area and Tripolis in central Peloponnese, Greece. We conduct urban design simulations by:i) Increasing green spaces to absorb heat, provide shade, and promote evapotranspiration, thereby reducing surface temperatures and mitigating UHI effects.ii) Implementing shading structures and urban canopies to offer shelter from direct sunlight.iii) Integrating water features to assess the effectiveness of incorporating water bodies like ponds, lakes, and fountains in the studied urban environments. Water features act as natural heat sinks, dissipating excess heat through evaporation and creating cooling microclimates.Furthermore, the model's optimization capabilities allow for fine-tuning these scenarios to achieve the best outcomes. By iteratively adjusting parameters and variables, planners can tailor mitigation strategies to specific urban contexts, considering factors such as local climate, population density, and infrastructure constraints. Optimizing mitigation scenarios for UHI hot spots represents a proactive approach toward enhancing urban resilience and sustainability. By leveraging simulation and optimization, cities can develop targeted interventions that mitigate heat-related risks and foster more livable and resilient urban environments for current and future generations.
Rossby waves sources over the Eastern Northern Pacific and their impact on the global atmosphere from a set of CMIP6 large ensembles
Authors: Fuentes Franco Ramon , Scaife Adam , Lockwood Julia , Dunstone Nick , Koenigk Torben
Published: July 2024

The Rossby Wave Sources (RWS), RWS trigger wave-like patterns arising from the upper troposphere of the north-eastern Pacific region, causing a response around the Northern Hemisphere with alternating regions of positive and negative correlation values between RWS and geopotential height at 500 hPa (Z500). Increased RWS intensity during summer is related to negative temperature anomalies over western North America, and positivetemperature anomalies over eastern North America, concurrently with increased precipitation over the western subtropical Atlantic and Northern Europe during summer. Colder than normal conditions in the North Pacific Ocean intensify the RWS and its impact on the global atmospheric circulation. We use 7 CMIP6 large ensembles for the period 1950-2014 to analyse how they reproduce the response in the global atmosphere to RWS over the North-eastern Pacific Ocean. The waveguides that RWS produce from the North-eastern Pacific around the globe show that CMIP6 large ensembles have displaced crests and troughs from the North-eastern Pacific compared to the locations of ERA5, although all of them show the spread of the signal worldwide.This location displacement of crests and troughs relies on how intense compared to ERA5 is the bias of the modelled westerly subpolar jet stream intensity reaching Europe from the North American continent. Models with a stronger bias in intensity show that the negative RWS-Z500 correlations over Scandinavia are weakened. Correspondingly, the same applies to the south-to-north component of the bias at 200 hPa. As in ERA5, the CMIP6 large ensembles show that warmer than normal SST over the North Atlantic, constraint the teleconnection only to the North American continent.
Intraseasonal shift in the wintertime North Atlantic jet structure projected by CMIP6 models
Authors: Garcia-Burgos Marina , Ayarzagüena Blanca , Barriopedro David , Woollings Tim , Garcia-Herrera Ricardo
Published: July 2024

The projected changes of the wintertime North Atlantic eddy-driven jet (EDJ) under climate change conditions have been extensively studied in recent years. Although most previous studies agree on a squeezing and elongation of the EDJ over Europe, there are still large uncertainties related to the intensity and latitude. In particular, some studies detect an intensification of the jet core region. However, there is no consensus as some studies find it insignificant or do not detect it. Similarly, the EDJ latitude in winter present a strong inter-model spread, spanning from poleward to equatorward responses. Here, we use a novel multiparametric description of the EDJ to scrutinize the EDJ projections of a CMIP6 multi-model ensemble. Further, we analyze separately these projections in early and late winter. Our results show a non-stationary response of the EDJ latitude through the winter, presenting a poleward migration in early winter and equator shift in late winter. This intra-seasonal shift is related to the climate change response of the different drivers. In particular, thermodynamic processes, involving the change in the 200hPa meridional temperature gradient and the North Atlantic sea surface temperature warming hole are found to influence the early winter change of the EDJ latitude. As for late winter, dynamical process related to the stratospheric vortex response to climate change plays a major role on the EDJ projections. Model biases also have an effect in the EDJ latitudinal projections. Relatedly, the well-established future squeezing of the winter EDJ is no longer found, suggesting it is an artefact from mixing intra-seasonal responses.
Revisiting a 24-year database of tornado damage paths using the new International Fujita (IF) scale
Authors: Rodríguez Oriol , Bech Joan , Castán Salvador
Published: July 2024

Tornadoes are the meteorological phenomenon capable of producing the most intense surface winds in the Earth, sometimes exceeding 100 m s-1. Tornado wind speed can rarely be measured in-situ using anemometers and radar. Nevertheless, it can be estimated through an analysis of the observed damage, especially when performing in-situ damage surveys (Rodríguez et al., 2020). The Fujita (F) scale (Fujita, 1971), which relates damage on buildings and forest with wind speed, was proposed with the aim of assessing tornado intensity. In the early 2000s was revised by the Texas Tech University proposing the Enhanced Fujita (EF) scale (WSEC, 2006). Both F and EF scales are broadly used, although it is hampering to apply them out of the USA because most damage indicators are related to typical building structures of that country, which are significantly different from those which are common in other regions.Recently, it has been proposed the International Fujita (IF) scale, which has been developed by several contributors from European universities and meteorological services coordinated by the European Severe Storm Laboratory (ESSL, 2023). IF scale considers a large variety of constructive structures and its sturdiness. This allows carrying out a detailed wind speed estimation based on damage surveys.In this work we revisit the 122 tornadoes included in the Catalonia tornado database 2000-2023 (NE Iberian Peninsula) with the aim of classifying events according to the new IF scale. We analyse and discuss spatial and temporally the results. Moreover, we compare them with previous classifications performed using F and EF scales, which showed that 92% of tornadoes reported in the region were weak (EF0 or EF1), whereas 8% were significant (EF2 or stronger) (Rodríguez et al., 2021). This study is partly supported by project PID2021-124253OB-I00. ReferencesESSL, 2023. The International Fujita (IF) Scale for tornado and wind damage assessments. European Severe Storm Laboratory, Wessling, Germany. https://www.essl.org/cms/wp-content/uploads/IF-scale_v1.0d.pdfFujita T.T., 1971. Proposed characterization of tornadoes and hurricanes by area and intensity. SMRP Research Paper, 91: 48.Rodríguez O., Bech J., Soriano J.D., Gutiérrez D., Castán S., 2020. A methodology to conduct wind damage field surveys for high-impact weather events of convective origin. Nat. Hazards Earth Syst. Sci., 20 (5): 1513-1531. https://doi.org/10.5194/nhess-20-1513-2020Rodríguez O., Bech J., Arús J., Castán S., Figuerola F., Rigo T., 2021. An overview of tornado and waterspout events in Catalonia (2000–2019). Atmos. Res., 250: 105415, https://doi.org/10.1016/j.atmosres.2020.105415WSEC, 2006. A Recommendation for an Enhanced Fujita Scale (EF-scale). Wind Science and Engineering Center (Texas Tech University), Lubbock, Texas, USA. https://www.depts.ttu.edu/nwi/Pubs/EnhancedFujitaScale/EFScale.pdf