bluuebunny/crossref_metadata_2025 huggingface dataset:
Dust trends in the Eastern Mediterranean and the surrounding deserts during 2001-2022
Authors: Logothetis Stavros-Andreas , Gkikas Antonis , Kazadzis Stelios , Kazantzidis Andreas , Amiridis Vassilis , Zerefos Christos
Published: July 2024

The Mediterranean basin is a region of great interest for studying atmospheric aerosols considering that it is one of the most vulnerable areas of the planet for climate change. Due to the extensive range of air masses that it receives, Mediterranean hosts a variety of aerosol species with dust particles constituting the major component of the total aerosol burden. Previous studies have demonstrated that across the Mediterranean, dust loads’ intensity is maximized in the eastern sector of the basin. The prevailing atmospheric circulation as well as the proximity with the most active deserts worldwide (i.e., Sahara, Arabian Peninsula) interpret the pronounced dust presence in the Eastern Mediterranean. The current study seeks to investigate the temporal variation of dust optical depth (DOD) in the Eastern Mediterranean, as well as in the neighboring deserts of North Africa and the Middle East. At a further step, emphasis is given on the understanding of the role/importance of the atmospheric and terrestrial mechanisms driving the obtained dust trends across various time scales. DODs are derived from the updated version of the MIDAS (ModIs Dust AeroSol) dataset, which delivers daily columnar optical depths, on a global scale and at fine spatial resolution (0.1° x 0.1°), over a 22-year period (2001–2022). A collection of ancillary datasets is employed to shed light on the factors governing dust life cycle components (i.e., emission, transport, removal). For the atmospheric state (i.e., synoptic circulation, near-surface winds), we are processing numerical products from the ERA5 reanalysis operated by ECMWF. Data from the Copernicus Climate Data Store (CDS) are exploited for depicting the temporal variability of the surface state (i.e., soil moisture, vegetation). Additionally, we are taking into consideration large-scale atmospheric circulation patterns (e.g., North Atlantic Oscillation). We anticipate that the obtained outcomes will contribute to the continuous effort of the modelling community to advance climate models utilized for the dust projections in the forthcoming decades.    This research has been supported by the CLIMPACT II (“Support for upgrading the operation of the National Network for Climate Change)”, funded by the Public Investment Program of Greece, General Secretary of Research and Technology/Ministry of Development and Investments.
The Role of Latent Heating in a North-Atlantic Baroclinic Environment Conducive to Extratropical Cyclone Clustering
Authors: Batelaan Thomas J. , Weijenborg Chris , Steeneveld Gert-Jan
Published: July 2024

A cluster of severe extratropical cyclones (Dudley, Eunice and Franklin) hit North-Western Europe within one week in February 2022, and caused widespread damage and fatalities by strong wind gusts and high accumulated precipitation amounts. These cyclones developed over the North-Atlantic within a baroclinic environment with strong jet streams accompanied by atmospheric rivers. Extratropical cyclone clustering is counterintuitive because individiual cyclones reduce large-scale temperature gradients and baroclinicity that are essential for their growth. We hypothesise that diabatic heating through latent heat release enhances the baroclinic environment favourable for secondary cyclogenesis. To quantify the influence of latent heat release on this baroclinic environment, we performed idealised model experiments with the Open Integrated Forecast System (OpenIFS) from the European Center for Medium Range Weather Forecastst (ECMWF). The latent heat of vaporisation constant was enhanced and reduced by 50 percent respectively.The control experiment captured the location, speed and direction of the jet stream, and the path and intensities of the individual cyclones well. The model results show that reduced latent heating weakens the jet stream strength, while enhanced latent heating strengthens the jet stream strength. The baroclinic environment responds similarly — i.e., the meridional temperature gradient decreases with reduced latent heating and increases with enhanced latent heating. We plan to apply the isentropic slope diagnostic for baroclinicity to quantify the diabatic contributions of latent heating to the baroclinic environment. We also plan to discuss the effects of latent heating on the individual cyclones. With this case-study we explore diabatic heating as a pathway for extratropical cyclone clustering.
GNSS Storm Nowcasting Demonstrator for Bulgaria
Authors: Guerova Guergana , Douša Jan , Dimitrova Tsvetelina , Stoycheva Anastasiya , Václavovic Pavel , Penov Nikolay
Published: July 2024

Global Navigation Satellite System (GNSS) is an established atmospheric monitoring technique delivering water vapour data in near-real time with a latency of 90 min for operational Numerical Weather Prediction in Europe within the GNSS water vapour service (E-GVAP). The advancement of GNSS processing made the quality of real-time GNSS tropospheric products comparable to near-real-time solutions. In addition, they can be provided with a temporal resolution of 5 min and latency of 10 min, suitable for severe weather nowcasting. This paper exploits the added value of sub-hourly real-time GNSS tropospheric products for the nowcasting of convective storms in Bulgaria. A convective Storm Demonstrator (Storm Demo) is build using real-time GNSS tropospheric products and Instability Indices to derive site-specific threshold values in support of public weather and hail suppression services. The Storm Demo targets the development of service featuring GNSS products for two regions with hail suppression operations in Bulgaria, where thunderstorms and hail events occur between May and September, with a peak in July. The Storm Demo real-time Precise Point Positioning processing is conducted with the G-Nut software with a temporal resolution of 15 min for 12 ground-based GNSS stations in Bulgaria. Real-time data evaluation is done using reprocessed products and the achieved precision is below 9 mm, which is within the nowcasting requirements of the World Meteorologic Organisation. For the period May–September 2021, the seasonal classification function for thunderstorm nowcasting is computed and evaluated. The probability of thunderstorm detection is 83%, with a false alarm ration of 38%. The added value of the high temporal resolution of the GNSS tropospheric gradients is investigated for a storm case on 24–30 August 2021. Real-time tropospheric products and classification functions are integrated and updated in real-time on a publicly accessible geoportal.
Evaluation of the sea-level rise in the northwestern Pacific marginal seas
Authors: Cha Hyeonsoo , Moon Jae-Hong , Kim Taekyun , Song Y. Tony
Published: July 2024

Because regional sea level rise can threaten coastal communities, understanding and quantifying the underlying process contributing to regional sea level budget are essential. In this study, we assessed whether regional sea level rise budget on the northwestern Pacific marginal seas (including the Yellow and East China Seas, South China Sea, and East/Japan Sea) can be closed with a combination of observations and ocean reanalyses over 1993–2017 but also with independent observations from in situ profiles including Argo floats and satellite gravity measurements since 2003. The sum of estimated components is comparable to the geocentric sea level rise for all marginal seas, representing the major contributions from land ice melt and sterodynamic components. While the mass loss of land ice accounts for a large fraction of the observed trend, the spatial trend and its interannual variability are dominated by the sterodynamic processes. The observation-based estimate further shows that along the continental shelves, the sterodynamic sea levels are substantially induced by ocean mass redistribution due to changes in ocean circulation. In contrast, local steric sea level contributes to the sum differently in spatial patterns, with stronger steric sea level rise in the deep water regions than the surrounding continental shelf regions. This result highlights the circulation-driven ocean mass change between the deep ocean and shallow marginal seas, which is playing a role in driving regional sea level rise trend and its variability along the continental shelves. In addition, our study demonstrates the utility of independent observational platforms for a process-based assessment by achieving the regional sea level budget closure.
Potential for subseasonal early warning systems for two heatwave-affected sectors of Switzerland: health and alpine permafrost
Authors: Büeler Dominik , Pyrina Maria , Sharaborova Elizaveta , Sivaraj Sidharth , Vicedo-Cabrera Ana M. , Imamovic Adel , Spirig Christoph , Lehning Michael , Domeisen Daniela I. V.
Published: July 2024

The projected increase in heatwave intensity and frequency will have far-reaching consequences for the human and natural environment of Switzerland. Two particularly important consequences are heat-related excess mortality in the low-lying areas and heat-related acceleration of climate-change-induced alpine permafrost thawing in high-elevation areas. The latter will potentially have far-reaching impacts on alpine hazards, ecosystems, infrastructure, and tourism. In this interdisciplinary project, we assess the potential of using subseasonal heatwave predictions as a basis for early warning systems for the above-mentioned sectors in Switzerland. For the health sector, we show that the (observation-based) statistical relationship between temperature and mortality in combination with downscaled subseasonal temperature forecasts can be used to predict mortality attributable to heat. We demonstrate that for two densely populated areas of Switzerland (Cantons of Zurich and Geneva) and two past hot summers (2018 and 2022) this system is able to predict individual heat-related mortality peaks up to two weeks ahead and anticipate longer-lasting periods of heat-related excess mortality up to four weeks in advance. For the alpine sector, we show that individual summer heatwaves can play an important role in accelerating permafrost thawing, even though the process is driven by long-term climate change. We demonstrate this with idealized sensitivity experiments with the SNOWPACK model (a physical model that predicts the evolution of the snowpack and the ground temperature below). They indicate that both the duration of heatwaves as well as their timing within an individual summer are important for the intensity of the ground warming in permafrost regions. In summary, this project demonstrates a large potential for using subseasonal heatwave predictions for early warning systems for the health sector. For the alpine sector, it highlights the potential importance of individual heatwaves for permafrost thawing and raises the question if subseasonal heatwave predictions could support monitoring and early warning systems in high-elevation areas in some way.
Reconstruction of strong winds in Gdansk, Poland, in the 18th century
Authors: Filipiak Janusz , Przybylak Rajmund , Pospieszyńska Aleksandra , Oliński Piotr , Araźny Andrzej
Published: July 2024

In the paper, we focused on the possibility of reconstructing information about occurrence of strong and very strong, potentially high-impact, winds in the 18th century. The analysis was dedicated to the city of Gdansk, for which there are massive sources of various historical data - a long series of instrumental data and detailed weather notes. Among instrumental data, sub-daily weather data on wind force and sea level pressure from the period 1739-1772 were used; they were measured from two to four times a day, depending on the year, by Michael Christian Hanov, a pioneer of regular meteorological instrumental measurements in Gdansk. He has developed a special classification of wind force, dedicated to the city's conditions. One of our tasks was a translation of Hanov’s classes of wind force into Bft scale. Instrumental data were combined with a weather notes made by the same observer. We compared the above mentioned information with detailed weather chronicles published by Gottfried Reyger (Filipiak et al. 2018). The monthly number of strong winds classified according to Brazdil et al. 2004 as: fresh and strong breeze (5-7°Bft), gale (8-9°Bft) and storm (10°Bft) was reconstructed. The results of analyzes based on various data sources indicate the differentiated monthly number of strong winds, depending on the source used. The further actions towards the elimination of some inconsistencies were taken. The frequency of occurrence of strong winds in the 18th century in Gdansk was further compared with contemporary results taken at synoptic station Gdansk Northern Harbour from the period 1987–2012.The work was done within a NCN project entitled The occurrence of extreme weather, climate and water events in Poland from the 11th to 18th centuries in the light of multiproxy data, supported by the National Science Centre, Poland, project No. 2020/37/B/ST10/00710.References:Brázdil R, Dobrovolný P., Štekl J., Kotyza O., Valášek H, Jež J., 2004, History of weather and climate in the Czech Lands VI: Strong winds, Masaryk University, Brno.Filipiak J., Przybylak R., Oliński P., 2018. The longest one-man weather chronicle (1721–1786) by Gottfried Reyger for Gdańsk, Poland as a source for improved understanding of past climate variability. International Journal of Climatology, 39, 2, 828-842, doi: 10.1002/joc.5845.
Verification, Validation and Vacancy-Profiling (VVV-P) as an assessment of quality and network growth potential of gridded climate data sets
Authors: de Baar Jouke H.S. , van den Besselaar Else J.M. , van der Schrier Gerard
Published: July 2024

Context. Over the past decades, we have seen important developments in climatological observational gridded data sets. One development is the increasing number of stations included in the gridding process. For any gridded data set, one might ask oneself: (a) How sensitive is the gridded data set to the number of stations? (b) How accurate is the gridded data set? (c) What is the potential improvement of the gridded data set if we add more stations, and does this potential improvement depend on the locally existing station density, the local terrain, etc.?Approach. We can learn from similar questions in engineering, specifically in the discipline of computational fluid dynamics (CFD). In this field of research, questions (a) and (b) are addressed in a standardized process of ‘verification’ (a) and ‘validation’ (b). The results of a verification and validation study are usually reported in terms of a grid convergence index (GCI) and (cross-)validation results. This approach was standardized by Roache in his work Verification and Validation in Computational Science and Engineering (Hermosa Publishers, 1998). We aim to apply the same procedure to gridded data sets. In this way, our approach is a way of interdisciplinary exchange of methodology.In addition, we analyze the effects of adding stations by tracking their type of location, terrain, etc. (part of which might also be used as covariates during gridding) when we quantify their effect on the gridded data set. In this way, we can train a simple machine learning model of how sensitive the gridded data set is to inclusion of stations with specific characteristics. The aim is to identify which type of stations, based on their characteristics, would be the most valuable addition to the data set. The last step (c), we name ‘vacancy-profiling’.Application. As a first study, we apply this approach to the E-OBS gridded data set for daily mean wind speed. This is an interesting data set, since the network density has increased significantly over the years, because the gridding process includes the use of covariate information which gives more details in the verification and validation processes.
Collaborative data-driven quantitative impact forecasting: applications in storm damage, human health and wildfires
Authors: de Baar Jouke H.S. , Pereira Marghidan Carolina , van der Schrier Gerard , van den Besselaar Else J.M.
Published: July 2024

Context. Extreme weather events are affecting society in unprecedented ways. Weather and climate services, including early warnings, play a fundamental role in preparing for and responding to these events, ultimately reducing loss and damage from the weather. In 2024, the EEA published the European Climate Risk Assessment, identifying different types of extreme weather as some of the most important climate change risks. To prepare for and respond to the rising weather and climate risks, the WMO has promoted the move towards impact-based forecasts (WMO, 2015, 2021). Knowing what to expect in terms of impacts is much more actionable for people and enables decision-makers to take targeted, cost-effective, and informed decisions (Harrowsmith et al., 2020). For some time, the Royal Netherlands Meteorological Institute (KNMI) and its Early Warning Centre (EWC) have been working towards impact-based warnings.Approach. Within the context of early warning services, KNMI and its EWC are experimenting with quantitative impact forecasting: "not what the weather will be, but what the weather will do."  Through collaboration with decision-makers and end-users, we apply data-driven methods to make quantitative forecasts of impact. We provide these quantitative forecasts as an ensemble, so that the stakeholders can base their decision on the expected impact and the uncertainty of the forecast. We apply a general machine learning framework to train a model on the observed weather and impact data for the Netherlands, the latter being provided by the stakeholders. Then, we use this model to derive quantitative two-week impact forecasts.Results. We show results for three different fields: storm damage, human health, and wildfires. The storm damage results are aggregated to a 10 x 10 km spatial resolution and 24-hour time resolution, and we provide a two-week forecast of the expected number of daily storm damage emergency calls as received by the fire services at the combined emergency services dispatch centre. We are collaborating closely with the emergency service provider to communicate these quantitative impact forecasts in an efficient way. For human health (cardio-vascular and respiratory fatalities) as well as wildfires (nature fires and road-side fires), we are currently working on quantitative impact forecasts aggregated at the national and monthly levels. The spatial and temporal scale of forecasts will be further improved to the provincial and weekly levels. Lastly, we will highlight the current limitations and challenges of impact-based forecasts based on our practical experience, and further research needed in this area.
Identification of past extreme precipitation events and their connection to recorded impacts: a multi-data and multi-method assessment over the Central-Eastern Alps.
Authors: Enigl Katharina , Crespi Alice , Lehner Sebastian , Haslinger Klaus , Pittore Massimiliano
Published: July 2024

Extreme hydro-meteorological events are increasingly prevalent in southern Europe, particularly in the European Alps, posing significant threats to ecological and socio-economic systems. The accurate detection and analysis of these events require a nuanced definition of what constitutes "extreme." While statistical approaches typically define extremes based on the tails of probability distributions, it is essential to recognize that the severity of these events may not always align with statistical extremes. Impact-related thresholds can vary spatially and temporally, making a single absolute threshold inadequate for capturing extremes across different locations, time periods, and seasons.In this study, we focus on identifying and characterizing extreme hydro-meteorological events in a transboundary Alpine region between Austria and Italy from 2003 to 2021. We employ various definitions of extreme events that consider spatiotemporal aspects and utilize multiple datasets. Daily accumulated precipitation serves as the primary parameter due to its widespread availability across datasets and its role as a triggering factor for various hazards like landslides, debris flows, and floods.We employ three statistical methods to detect extreme events: regional-scale identification of highest daily precipitation amounts, local-scale detection of high-intensity daily precipitation values, and identification of exceptional daily precipitation records relative to average conditions for specific periods of the year. These methods are applied to four gridded precipitation datasets, including observation and reanalysis products, each with different technical specifications.Subsequently, we compare the identified events from each method-dataset combination with existing records of gravitational mass movements and fluvial floods in the Austrian-Italian border region to assess their ability to detect actual impacts. Findings suggest that a majority of detected precipitation extremes (e.g., 74% for regional scale identification with reanalysis data) correlate with observed impacts. However, different method-dataset combinations exhibit varying strengths and weaknesses, reflecting the characteristics of the dataset and/or statistical method employed. Some combinations show lower performance in detecting impactful events due to conflicts between dataset resolution and statistical method requirements.
Destination Earth On-demand Extremes case studies: results, challenges and lessons learnt at DMI
Authors: Baordo Fabrizio , Benacchio Tommaso , Alerskans Emy , Yang Xiaohua , Thorsen Søren
Published: July 2024

The on-demand Digital Twin Extreme (DTE) is part of the European Destination Earth initiative which, during phase 1 of the project (2022-2024), has involved the cooperation of a large number of European National Weather Centers. The goal of the on-demand DTE is to provide a technical framework which is capable of running different flavours of the ACCORD forecast  models (e.g. HARMONIE-AROME, AROME and ALARO) at very high resolution. The forecast predictions are expected to be triggered on demand for high-impact weather events within a regional domain (the so-called Limited Area Model) at subkilometre scale (e.g. horizontal resolutions of 750, 500 or 200 metres). In this poster, we will present some case studies which were explored at the Danish Meteorological Institute (DMI) in the contest of DTE phase 1. We will provide an overview of the challenges we faced looking at different weather events (such as flooding, extreme winds and precipitation) when the high resolution forecast model is initialised by lateral boundary conditions which can be from either the operational ECMWF Integrated Forecasting System (about 9 km resolution) or the Global Continuous Extreme Digital Twin (about 4.5 km resolution). Development and testing of data assimilation within the high resolution domain were not considered in the phase 1 of the project. Hence, in the case studies we focused on exploring the benefits and limitations of the LAM high resolution forecasts when the system is simply initialised with one of the ECMWF global systems. Overall, we will show the predictability capacity of the on-demand DTE and the added value of the increased model horizontal resolution.
Automated identification and tracking framework for hazard cataloging
Authors: Cazzaniga Greta , Bonhomme Ludyvine , Burq Adrien , Vrac Mathieu , Faranda Davide
Published: July 2024

Event identification and tracking tools have become essential in weather and climate research due to the rapid growth of weather and climate model data. These algorithms automate the detection of extreme weather-related events and hazardous phenomena and their corresponding features, thereby enhancing predictive capabilities. Our study introduces an open and adaptable framework designed for the automated identification and tracking of various hazard types from a Lagrangian perspective, spanning multiple spatial and temporal scales and providing insights into the dynamics and behavior of hazardous events. This framework is versatile and applicable to a range of scenarios from historical hazard analyses to future climate scenarios evaluation. Additionally, this work facilitates the investigation of weather patterns that give rise to the hazards and enables the assessment of their impacts. The algorithm relies on connected components and distance thresholds to identify and track events in space and time, permitting event merging and splitting dynamics over time. Furthermore, it characterizes events based on diverse spatio-temporal features such as duration, volume, intensity, and trajectory. The framework includes visualization tools for displaying event trajectories. It enables statistical analyses of detected time series derived from historical records and climate model outputs (e.g., identifying trends, exploring correlations between feature pairs, and analyzing feature distributions). To prove the framework's efficacy and versatility, we applied it to detect major hazards including heatwaves, cold spells, heavy precipitation events, hydrological droughts, and even combinations of these events identified as compound events. Leveraging ERA5 reanalysis, satellite data, and radar data we constructed an extended historical catalog of these hazards in France and conducted statistical analyses to characterize event properties and structures. Subsequently, applying the framework to Cordex data allowed us to assess potential future hazard scenarios.
ICON-XPP in the CERISE project: a first set of seasonal hindcasts
Authors: Noll Nils , Romanova Vanya , Sgoff Christine , Fröhlich Kristina , Geppert Gernot
Published: July 2024

The Copernicus Climate Change Service Evolution (CERISE) project, as an EU-HORIZON project, aims to enhance the quality of the C3S (Copernicus Climate Change Service) reanalysis and seasonal forecast portfolio, with a focus on land-atmosphere coupling. CERISE will develop new and innovative ensemble-based coupled land-atmosphere data assimilation approaches and land surface initialisation techniques to pave the way for the next generations of the C3S reanalysis and seasonal prediction systems. Deutscher Wetterdienst is developing its land data assimilation for the initialisation of seasonal forecasts with ICON-XPP. ICON-XPP (ICON eXtended Predictions and Projections) is not only the state-of-art climate modelling system in Germany but also an effort to unify knowledge and experiences from many institutes in one model system that can deliver seamless weather and climate simulations. We aim to include snow analysis, soil moisture analysis and leaf area index assimilation into our climate forecast data assimilation system. Here we present a baseline version of multi-year historical forecasts, so-called hindcasts for a period of 1993 to 2022. The current system to generate initial conditions consists of an Ensemble Kalman Filter for the ocean while nudging is applied in the atmosphere. Further, annually changing ESA-CCI land cover replaces the LUH2 data during this time, which is processed into plant functional types (PFTs) for use with the land model JSBACH. Results from these first seasonal hindcasts using the ICON-XPP model will be shown and discussed. Of special interest are the start months for the boreal spring and autumn forecasts, as the impact of land data assimilation is expected to be strongest.
Development of the 2D/1D Coupled S-RAT Model for Flooding Simulation Dual Drainage in watershed
Authors: Lee Dongseop , Kim Byungsik
Published: July 2024

Increasing urbanisation and climate change have had a significant impact on urban infrastructure due to the expansion of impervious surfaces. These surfaces lead to excessive runoff, which strains urban drainage systems beyond capacity and often causes damage. Traditional rainfall-runoff models often fail to adequately reflect the specific characteristics and limitations of urban pipe networks. These models typically use the Curve Number (CN) method to categorise land into eight types, including urban areas. This method primarily addresses surface and subsurface runoff without considering important urban infrastructure components such as drainage pipes and storage facilities. Recognising these shortcomings, this paper presents a new concept of distributed rainfall-runoff model, called S-RAT Urban, which incorporates the urban pipe network in the watershed analysis. The model incorporates both temporal and spatial variability of hydrological processes to improve the accuracy of runoff prediction. The model uses a distributed approach that applies the curve number method to better represent urban environments, including the effects of overlooks. The model uses a grid-based input system that uses Digital Elevation Models (DEMs), land use and soil type data to generate flow directions. The traditional two-dimensional (2D) flow direction mapping used in urban areas is converted to a one-dimensional (1D) pipe network model. This conversion is critical to realistically simulate flow through urban drainage systems. In addition, flow within the pipe network is calculated using continuous and impulse equations to provide a dynamic and realistic representation of the urban hydrological response under different weather conditions. This method not only identifies the variability of the hydrological cycle under natural conditions, but also incorporates critical urban infrastructure into the distributed model, providing a more comprehensive and practical tool for urban catchment management.
Assessment of the horizontal resolution and an emission inventory in two different regional climate models in the FOCI project
Authors: Machado Crespo Natália , Villalba-Pradas Anahí , Verma Shruti , Karlický Jan , Huszár Peter , Belda Michal , Halenka Tomáš
Published: July 2024

The FOCI project (“Non-CO2 Forcers and their Climate, Weather, Air Quality and Health Impacts”, https://www.project-foci.eu/wp/) aims to better understand the impacts of key non-CO2 radiative forcers, to assess where and how they arise, and their impact on the climate system, with a final goal of providing tools to investigate mitigation and adaptation policies incorporated in selected scenarios of future development, targeted at Europe and other regions of the world. As part of the Work Package 4 from the FOCI project, which is responsible for tuning, testing and performing the long-term simulations with different regional models downscaling reanalysis and global climate models, we present an assessment of initial tests in WRF and RegCM5 with different domains over Europe. This study is divided into two parts: assessing the impact of 1) the chemistry in the 27-km domain that covers Europe, by comparing with a control simulation and a reference data, and 2) the nested 9 and 3-km domains on meteorological variables, such as precipitation, temperature, and horizontal winds. The 3 km convection-permitting (CP) simulations cover the city of Prague, one of the satellite cities from FOCI project, and an extreme weather event will also be evaluated. Data from ERA5 and assimilated chemistry by Copernicus Atmosphere Monitoring Service (CAMS) are used as boundary conditions, and E-OBS for validation the outputs. Some results show that simulations with chemistry tend to be slightly drier and warmer compared with no chemistry. Furthermore, although overestimating the precipitation over the Czech Republic territory, the 3-km CP simulation shows improvement in capturing the peaks of precipitation for the event.
A Local Wave Activity Interpretation of the Large Scale Drivers Behind the Projected Drying of the Mediterranean
Authors: Sandler Dor , Saaroni Hadas , Ziv Baruch , Ton Rotem , Harnik Nili
Published: July 2024

The projected drying of the Mediterranean basin is a robust signal of future climate change. Dynamically, this is manifested as a large anticyclonic anomaly covering the region, alongside a decrease in cyclonic activity. Various processes have been previously proposed as drivers of this trend, both thermodynamical (decreased land-sea temperature gradient) and dynamical (intermediate-scale stationary wave response, poleward shift of the jet stream). Several elements of the North Atlantic large-scale circulation are known to affect Mediterranean cyclonic activity (extratropical storms, jet stream position, weather regimes), individually and through mutual interactions. However, their contribution to the overall drying remains an open question.In this work, we use the framework of Finite Amplitude Local Wave Activity (FALWA; Huang & Nakamura, 2016) to deconstruct the role of the North Atlantic circulation in the projected changes downstream. FALWA is a diagnostic that keeps track of the wave activity ”stored” within circulation undulations, relative to a zonalized flow. It obeys an exact conservation relation; thus, its local rate of change is either due to a flux convergence, or to non conservative source-sink terms. This allows for a closed mechanistic budget analysis of the response, differentiating between horizontal advection by the mean flow, barotropic and baroclinic processes, and diabatic forcing.We analyse this budget in a 10 member CMIP6 ensemble and investigate the multi-model mean circulation response and ensemble spread over the North Atlantic and the Mediterranean basin. Preliminary results show a prominent baroclinic contribution over the eastern North Atlantic combined with enhanced advection of upper tropospheric potential vorticity towards Europe. Both elements imply that the shifting of the North Atlantic storm track plays a role in the projected drying trend of the Mediterranean.
OceanUCA: towards the adaptation and consolidation of an Operational Oceanographic and Atmospheric System to improve the observation and forecasting of coastal physical processes in Andalusia
Authors: Román-Cascón Carlos , Álvarez Oscar , Izquierdo Alfredo , Benavente Javier , Gómez-Enri Jesús , Fernandez-Montblanc Tomás
Published: July 2024

The OceanUCA project* focuses on the development of an operational platform to integrate and update already existing operational tools (such as the OceanMap UCA system developed by the group in the framework of previous projects), including new observational systems and higher-resolution numerical model products.The methodology of the project aims to improve and adapt the computational resources to respond to the current societal needs and to the higher computational time demand of the new models. This is mainly motivated by the growing spatiotemporal resolution of the models used to effectively respond to specific environmental coastal problems (e.g., oil spills, wrecks, marine and atmospheric heat waves, extreme events tracking, etc.). OceanUCA will be based on tools generated from observational data and numerical model outputs (both atmospheric and hydrodynamic), specifically designed and configured to reach their maximum resolution on the coast of Andalusia (Southern Spain). Besides, the new operational platform OceanUCA will be coordinated with other Spanish and European operational oceanographic services.The ultimate aim of the project will serve to detect specific effects associated with climate change, to enhance the environmental protection of the area, to facilitate the conservation of natural resources, to develop early-warning products, to improve the short, medium, and long-term forecasts, and to help using adequately the set of ecosystem services that the coastal environment offers. Besides, we hope the new platform will help the decision-making from institutions and third parties through the real-time (and forecast) monitoring of marine and atmospheric processes on the coast of Andalusia.In this work, we will show details about the platform, including overviews of the hydrodynamic and atmospheric models used and the associated observations, that will be extended in the frame of related projects currently developed.* OceanUCA is a project recently funded by the 2023 call for Marine Sciences I+D+i projects in the frame of: “Plan Complementario de Ciencias Marinas of Junta de Andalucía” and “Plan de Recuperación, Transformación y Resiliencia” (NextGenerationEU funding).
Assessment of the Urban Heat Island Effect in Paris under different circulation weather types
Authors: Fernández-Duque Beatriz , Pérez Isidro A. , García M. Ángeles , El Kenawy Ahmed M. , Vicente-Serrano Sergio Martín
Published: July 2024

Urban heat island (UHI) effect poses a significant human-induced challenge to urban communities, jeopardizing their livelihoods. Amplified by the upward global temperature trends, as a consequence of climate change, the effects of UHI have increasingly become severe. This manifests in crucial social (e.g., increased heat-related illnesses and mortality rates, particularly affecting vulnerable populations), economic (e.g. difficulties of some groups to access to cooling infrastructure for mitigating heat stress) and environmental implications (e.g., higher heat stress on vegetation, increase risk of species loss, increase of ozone pollutant levels). The current study examined the daytime and nighttime UHI effect in the region of Paris from 1990 to 2022. The study presents a novel method for assessing UHI using readily available data from the NCEP-NCAR Reanalysis 1 dataset (at almost 1.8 km spatial resolution) and low computational resources, enhancing the feasibility of UHI monitoring and analysis. By integrating daily circulation weather type (WT) classification with UHI analysis, this study elucidates the influence of weather patterns on UHI events.  Results showed that the most common WT were the anticyclonic (A) and the cyclonic (C) with almost 25% and 10% of occurrence respectively, combined with two additional directional types: the Southwestern (SW) and the Western (W) type which account for around 10% of the total cases for both WT. The anticyclonic type predominance is mainly due to the migration of the Azores anticyclone towards the area of study which is linked with higher urban heat island intensities either for maximum and minimum temperatures, especially during the autumn season. These anticyclonic situations were mainly associated with anomalous daytime and nighttime temperatures and accordingly a broader extension of Paris region affected by the UHI effects. It should be noted that a highest UHI effect was found during summer and especially noticeably for the nighttime. The findings of this study highlight the escalating severity of UHI impacts, exacerbated by global temperature trends due to climate change. Overall, this study highlights the urgent need for proactive measures to mitigate UHI effects in urban areas, encompassing policy interventions, infrastructure improvements, and community resilience strategies. By comprehensively understanding the dynamics of UHI and its interactions with broader climatic patterns, stakeholders can develop targeted interventions to safeguard urban communities against the escalating challenges posed by UHI in the context of climate change.Keywords: Urban Heat Island assessment, climate risks, impacts, Lamb Weather Types, spatial analysis, Paris.
MeteoMuntanya.cat: a project on weather, mountaineering, and safety 
Authors: Esteban Vea Pere , Serra Uró Aleix , Pons Casadesús Quim
Published: July 2024

There has been a continuous year-on-year increase in mountaineering injuries and fatalities in Catalonia, partly related to adverse weather conditions such as thunderstorms, mist, strong winds, blizzard, cold temperatures, among others. 

In this context, in November 2016, meteomuntanya.cat was launched, a specialized meteorological contents webpage resulting from the collaborative effort between the Meteorological Service of Catalonia (SMC) and the Catalan Mountain Clubs Federation (FEEC).  

MeteoMuntanya provides operational, informative and awareness-raising information and products aimed at reducing accidentality. 

Firstly, various tools are available for planning our route, climb or traverse in detail. 

“Mountain conditions” offers a written weather forecast focused on weekends and holidays. Special symbology is used to highlighting forecasted occurrences such as strong winds, reduced visibility due to mist, heavy or persistent rain, thunderstorms and lightning activity, snowfalls and blizzard, iced snow surface, and thermal comfort (cold/hot). Safety comments and recommendations may also be included. 
To complete the written forecast, the “peaks weather” provides daily semiautomated forecasts (3 km resolution WRF) for over 300 peaks over the Catalan massifs, with a 3-day window. 
Furthermore, users can also find real time and daily anomaly snow depth data, forecast focused in mountain routes conditions, and detailed conditions for some official competitions (as trail-running or mountain skiing). 

To expand the “mountain culture” and reinforce awareness-raising, the “blog” section offers written content (2-5 minutes reading) on topics like climate change, Catalan massif climates, or mountain weather. Recent examples include “Forecasting mist”, “Winter anticyclone and snow” or “Climate change and mountains activities”, articles which are also permanently included in "Vèrtex," the FEEC review received by over 40,000 members (federates). 

Finally, the section “mountain and safety” serve as a reference place for individuals, mountain clubs, and schools seeking education resources. Examples include YouTube videos on weather hazards during mountaineering featuring recognized mountaineers such Araceli Segarra, Ferran Latorre or Claudia Sabata. There is also free access to online seminars on topics like mountain blizzard or thunderstorms and lightning.  

All MeteoMuntanya contents are consistently disseminated through the social networks of the Meteorological Service and the Mountain Federation, with more than 350.000 and 40.000 followers in X, respectively. 

With this presentation, we aim to showcase our 8 years of experience and explore opportunities for coordinating efforts with other meteorological services to provide consistent mountain weather safety information and products. 
Exploring how a warmer Mediterranean Sea affects the origin and development of destructive Tropical-Like Cyclones IANOS and DANIEL
Authors: Redaelli Gianluca , Liguori Giovanni , Cavicchia Leone , Miglietta Mario Marcello , Bonaldo Davide , Carniel Sandro , Calvo-Sancho Carlos , Martin Maria Luisa , González-Alemán Juan Jesús , Richi Antonio , Ferretti Rossella
Published: July 2024

In a complex contest of climate change, we observe the evolution of extreme events that greatly challenge many areas of human life. Although the Mediterranean Sea is a relatively mild basin, it is however characterized by, occasionally intense cyclones with tropical-like characteristics known as Tropical-Like Cyclones (TLC). Many studies have highlighted that sea surface temperature (SST) distribution play a crucial role in modulating the intense air-sea exchange, hence controlling both development and evolution of TLCs. However, given the complex interplay among ocean mixed layer, heat content and temperature, the role of the mixed layer depth (MLD) and SST Anomaly is of paramount importance. In this study we investigated the role of both SST anomaly, horizontal gradients and MLD profile on the origin and evolution of a recent record-breaking TLC (named IANOS and DANIEL). IANOS and DANIEL are originated over the southern Ionian Sea. The first made landfall over Greece mainland coast and DANIEL made landfall over Libyan coasts. These TLCs developed over a basin where a positive SST anomaly up to 4 °C was detected, which coincided with the sea area where it reached the maximum intensification and strength. We conducted a series of experiments using an atmospheric model (WRF - Weather Research and Forecasting system) driven by underlying SST (standalone configuration), either with daily update or coupled to a simple mixed-layer ocean model (SLAB ocean), with SST calculated at every time step using the SLAB ocean for a given value of the MLD. Sensitivity tests were performed increasing or decreasing MLD depth by 10 m, 30 m, 50 m, 75 m, 100 m, removing the horizontal gradients, removing the SST anomaly. Then, possible past and future climatological scenarios of MLD thickness were identified and tested. Preliminary results show that the MLD influences not only the intensity of the cyclone but also the structure of the precipitation field both in terms of magnitude and location. The fundamental role of the SST anomaly was also found to be essential to provide intense characteristics to IANOS and DANIEL. Results deserve further investigation in the context of climate change scenarios that can provide useful insights into impact on coastal civil and economics in the whole Mediterranean region.
Towards largely automated monthly and annual climate reports for Switzerland
Authors: Zubler Elias , Anet Julien , Bader Stephan , Collaud Coen Martine , Duding Olivier , Giordano Alexander , Panziera Luca , Posselt Rebekka , Schlegel Thomas , Schwierz Cornelia , Croci-Maspoli Mischa
Published: July 2024

The Federal Office of Meteorology and Climatology MeteoSwiss has the mandate to keep the Swiss population informed about the status of the local climate and climate change. For this purpose, MeteoSwiss is providing a series of recurring bulletins that appear on a monthly, seasonal and annual basis and in three national languages. These bulletins are mainly produced for the media as a blog post on the MeteoSwiss website (meteoswiss.admin.ch) and the MeteoSwiss smartphone app two days before the end of the respective period (preliminary data), and as a PDF for download on the website ten days after the end of the reported period (definite data). In addition, the recurring bulletins are accompanied by situational reports on weather events and climatological issues throughout the year.Over the last twelve years, this variety of information has been published largely regardless of changes in the media landscape, publication channels, reading habits and user demands. A closer look at our portfolio of reports showed the following key findings:The main effort of written reporting on climate in Switzerland today lies in the recurring bulletins despite a great potential for automation.
Several recurring reports build on each other, some of which are redundant.
In recent years, there have been occasional bottlenecks in the resources available, particularly at the end of months or seasons when the recurring reports are due.
Currently, there are major gaps in MeteoSwiss climate information, especially on the local scale (cantonal, communal) and in event reporting.
The coverage of target groups shows that the focus of certain reports could be sharpened.
The distribution channels for the individual bulletins and reports should be revised.
As a consequence of this analysis, MeteoSwiss is about to revise its climate communication. The long-term goal of the project is to automate the recurring bulletins as much as possible, in order to make more resources available for event reporting. The automation has other benefits, e.g., with regard to regionalization of climate information or by simplifying the adaptation of certain reports to different target groups. MeteoSwiss has already gained positive experience with automated reports (e.g., bulletin for energy management). Here, we show how we plan to automate the climate bulletins, which form the reports are expected to take, what tools we are planning to apply for this purpose and how we intend to intensify event reporting.