bluuebunny/crossref_metadata_2025 huggingface dataset:
On the generation of a meteotsunami, the case study of supercell storm, over Adriatic Sea
Authors: Memmola Francesco , Vilibic Ivica , Coluccelli Alessandro , Brocchini Maurizio , Corvaro Sara , Penna Pierluigi , Falco Pierpaolo , Ricchi Antonio , Ferretti Rossella
Published: July 2024

In the afternoon of July 22, 2023, a very intense thunderstorm developed over the central Po Valley. It  quickly cross the Adriatic sea traveling from the center of the Po Valley to the Croatian coast, moving in the direction northwest-southeast. The thunderstorm speed ranged between 50 and 80km/h, with a downdraft exceeding 100 km/h, wind gust up to 120 km/h, which led to the formation of intense hailstorms with hail larger than 8 cm. The pressure difference between the front and central regions of storm,  reaced  6 hPa, with peaks up to 10 hPa. As the supercell moved towards the coast, the combined effects of the downdraft and the pressure variation, along with the storm's speed, likely triggered a meteotsunami. Both amateur evidences and instrumental observations showed the propagation of a  wave along the Adriatic coast, from North to South, with an amplitude of about 40 cm and a period of approximately 20 minutes. This phenomenon was observed from Ravenna (where the stormcell moves from land to sea) to Ancona, San Benedetto del Tronto, and Ortona with a propagation speed comparable with the storm  speed thus, in good agreement with a possible Proudman resonance. Physical analysis and numerical simulations of the atmosphere and ocean were performed  using numerical models: WRF (Weather Research and Forecasting System), ICON (Icosahedral Numerical Model), and ROMS (Regional Oceanographic Modeling System), coupled with SWAN (Simulating Waves in Nearshore) at 1 km horizontal resolution. The atmospheric results accurately reproduced  the storm's structure and evolution. The coupled ROMS and SWAN model was performed to assess the individual impacts of the downdraft, the vertical component of the downdraft, the pressure surge, and the overall storm surge. This work presents the outcomes and key factors contributing to the generation and amplification of this phenomenon.
The added value of the co-production process delivering climate services in Niger
Authors: Tarchiani Vieri , Bacci Maurizio
Published: July 2024

Climate services are recognized as an essential tool for sustainable development in strategic and climate-sensitive sectors. In developing countries, particularly in Africa, the literature offers successful examples of application, especially in the agricultural sector, which is dramatically sensitive to climate variability and change. While, initially, particular emphasis was placed on the outcomes of these services and the benefits they provide to users, several authors have recently focused their attention on the process. A climate service is understood as a cyclical process in which various actors interact, exchange knowledge, and establish relationships and mutual trust. This co-production process primarily serves to bridge the gap between science and society, making it particularly suitable for developing countries. While several authors claim that the  co-production process improves the service usability, the intrinsic value of the process is rarely recognized. This study aims to describe the process and document its added value using the example of Niger as a case study. In Niger two services addressing drought and floods have recently been developed, tested, and operationalized. This experience provides valuable lessons that can benefit researchers and practitioners in both developed and developing contexts. The value of the collaboration between different disciplines (transdisciplinarity) and roles (complementarity), along with the iterative and interactive learning process, emerge as key elements allowing a continuous improvement of the services and strengthening relationships among actors.Based on the experience and perception of the stakeholders involved in Niger, we suggest considering the following four dimensions in evaluating the added value of the co-production process in climate services:Value added to the Climate Service co-production: the value created beyond more conventional approaches in service production, as well as the progressive technical enhancement resulting from the co-production process;
Value added to the Climate Service functioning: on the service efficiency/effectiveness in terms of access to information, uptake of the services, action by users and Monitoring/Evaluation;
Value added to the expansion of the service: on the service scaling-up, expansion and financial sustainability of the service beyond the initial funding period;
Value added toward new services: capacity building among actors and stakeholders to envision and develop new services.
While the results of this process are qualitatively described in the paper, they could serve as guidance for researchers and practitioners in adopting such an approach. Additionally, they could represent a tangible example for funders and policymakers of the  added value of the process. Finally, the paper recommends the capitalization of pilot experiences through the national and global frameworks for climate services.
Investigating Wind Potential in Rwanda
Authors: Uwajeneza Liliane , Tang Chao , Morel Béatrice , Sylla Bamba
Published: July 2024

Abstract: Transitioning to renewable energy (RE) sources such as solar, wind, and hydropower is crucial for mitigating climate change by reducing greenhouse gas emissions. In 2019, 640 million people in Africa lacked access to clean energy. In Rwanda, the energy context revealed a 52% share of non-renewable and a 44% share of renewable sources. However, Rwanda faces a shortage of electricity to meet demand, even with imports from neighboring countries. Therefore, Rwanda set a goal to electrify all households by 2024, aiming for 100% electricity access through enhanced generation capacity and cross-border interconnections. The country has significant potential for RE, particularly in hydro, solar, methane gas, peat, and geothermal resources. However, Rwanda's wind resource has not yet been exploited for power generation. Although wind power in Rwanda has provided possible solutions in some areas, such as water pumping, windmills, and electricity generation, its full potential remains untapped. The main goal of this study is to investigate the wind resource assessment of Rwanda, a landlocked country in East Africa, as part of its efforts to achieve a 60% RE share in the generation mix by 2030. This study focuses on assessing Rwanda's wind potential through comprehensive data analysis, using hourly wind speed and direction data at 10 m above ground level for the year 2023 from various Meteo Rwanda sites across the country, along with   gridded dataset of ERA5 reanalysis data at approximately 25 km spatial resolution at 10 m and 100 m. Additionally, the study used the WAsP model to validate by comparison the measured and modeled wind data from annual means to diurnal cycles.  The methods used include the Weibull distribution and logarithmic law to describe wind speed distributions, and extrapolating values to different hub heights by using ERA5 reanalysis data. Furthermore, capacitor factors are computed, and wind power density is determined for each site given. This research aims to investigate the wind potential of Rwanda, contributing to its sustainable energy transition.
Characterizing Onsets and Terminations of Soil Moisture Droughts in Europe
Authors: Kim Woon Mi , González-Rojí Santos J. , Simpson Isla R. , Kennedy Daniel
Published: July 2024

Determining the exact timing of the onset and termination of soil moisture droughts is complex due to their multifaceted nature and slow development. Nonetheless, understanding when droughts have commenced and ended and identifying circulation patterns involved during their life cycle is crucial to enhancing early prediction systems and preparedness for such events. Still, the onsets and terminations (O&T) of soil moisture droughts have not been fully explored in Europe. Thus, this study investigates the climatological characteristics, namely, duration, preferred seasons and associated circulation, of O&T of soil moisture droughts in the Mediterranean (MED) and central Europe (CEU). To this end, we use five soil moisture datasets developed using different approaches: ERA5-Land, Noah-LSM, CLM-TRENDY, GLEAM, and SoMo.ml. Our findings indicate that the duration of O&T depends mainly on the dataset. ERA5-Land exhibits shorter and GLEAM longer duration of O&T across Europe. The other datasets fall within that range. This disparity appears to be linked to how each dataset outputs evapotranspiration, thereby affecting the resulting water balance in the soil levels. Despite the differences in duration, all datasets consistently indicate the same preferred seasons for O&T: onsets occur more frequently during the wet seasons, specifically summer in CEU and winter in MED, and terminations tend to occur during the driest seasons. This temporal consistency suggests similar variability and the same drivers of O&T across datasets. Focusing on large-scale drivers of droughts, we found that onsets occur with more frequent positive North Atlantic Oscillation (NAO). Positive NAO drives persistent large-scale anticyclonic pressure patterns during onsets, supporting further progression into droughts. Interestingly, positive NAO conditions are not pronounced during the mature phase of droughts. Terminations do not necessarily require opposite negative NAO conditions. They are characterized by a weaker pressure field and increased precipitation over the continent. These findings on circulation emphasize the important role of the NAO in initiating dry periods, thus indicating that it can serve as an early warning for droughts.
Condensed water path in GCMs and RCMs simulations over Europe 
Authors: Penčevová Radka , Farda Aleš , Meitner Jan , Skalák Petr , Štěpánek Petr , Zahradníček Pavel
Published: July 2024

Condensed water path (CWP) is the sum of liquid water path (LWP) and ice water path (IWP). CWP is an essential parameter affecting a wide range of atmospheric processes including cloud properties, precipitation formation and both short and long wave radiation properties of the atmosphere. Therefore, it is desirable to validate this quantity in both global and regional model outputs and to quantify its impact on other climate characteristics. Finally, this knowledge could help to understand differences between CMIP5 and Euro-CORDEX climate simulations as they are discussed among modelers and climate change impact communities and lead to better representation of physical process in climate models. 

We focused on the area of Central Europe and recent climate and its projection according to scenarios RCP 4.5 and SSP-2.45. We have selected all model simulations containing CWP available from Euro-CORDEX initiative and CMIP5 and CMIP6 over Europe. CWP data were then aggregated for each of the 4 distinct ensembles (Euro-CORDEX high resolution, Euro-CORDEX low resolution, CMIP5 and CMIP6) in monthly time step and then compared to observations represented here by ERA5 re-analysis and CLARA 2.1 satellite measurements data. 

We have found that ERA5 and CLARA data agree well with each other. CWP available from CORDEX models and represented as ensemble mean is then significantly underestimated compared to the reanalysis, observation dataset and both CMIP ensemble means. CMIP5 models processed in the same way as CORDEX models then overestimate CWP compared to reanalysis and observations, whilst CMIP6 ensemble offers the best agreement with observed data. The future climate projections based on RCP 4.5 scenarios (CMIP5 and CORDEX models) and SSP-2.45 (CMIP6) models were also assessed. CMIP6 models then project statistically significant loss of CWP over the 21st century, CMIP5 data and CORDEX data project strong increase in CWP. However, values from both CORDEX ensemble means by the end of the century are still not reaching the levels from observed data.  
Three-dimensional Lagrangian microplastic transport simulations in the Gulf of Naples (Southern Tyrrhenian Sea)
Authors: Gifuni Luigi , de Ruggiero Paola , Cianelli Daniela , Pierini Stefano , Zambianchi Enrico
Published: July 2024

The high-resolution Campania Regional Ocean Model (CROM), coupled with an online Lagrangian particle tracking algorithm (TRACE), is used to investigate the horizontal and vertical behaviour of different (in terms of size and density) plastic polymer types during February and August 2016 in the Gulf of Naples, a coastal marine area of the southern Tyrrhenian Sea, heavily affected by anthropic stress due to the presence of numerous tourist attractions, high population density, and intense maritime commercial activity. The choice of a winter (February 2016) and a summer month (August 2016) in our simulations aims to understand how seasonality, and thus the different hydrological features of the marine environment, affect the 3D transport of plastic particles since variation of the seawater density also plays a critical role in the particle settling dynamics. The transport of passive particles is evaluated based on the three-dimensional Eulerian velocity fields provided by the ocean model. The virtual particles are released in several hot spot areas in the Gulf of Naples where most of the marine debris is supposed to come from: the Sarno River mouth, the harbour of Naples, and the coastal area of Bagnoli. A sensitivity analysis on the vertical sinking for negatively buoyant particles is carried out. The sinking behaviour is determined by the settling velocity, which depends on the physical properties of the individual litter item as well as on the hydrodynamical features of the marine environment. Different numerical experiments are carried out to evaluate the effect of marine dynamics on three-dimensional transport.
Intercomparison of Measurements at Climate Reference Stations in Germany
Authors: Knerr Isabel , Friedrich Karsten , Imbery Florian
Published: July 2024

To ensure consistent time series of climate observations, the German Meteorological Service (DWD) operates out parallel measurements (e.g. wind and precipitation measurements) at climate reference stations. Parallel measurements of subsequent generations of operational measurement systems are carried out over several years at selected ten locations with different environmental conditions in order to evaluate the quality of the data obtained, to analyse systematic differences between the instrument types and to ensure the homogeneity of the data series.A key feature of climate reference observations is that they are monitored consistently over long periods of time to ensure a high degree of comparability of observations. Inconsistent data series are of limited use in climate research. In order to assess the consistency of climate observations, these time series must be described in detail using metadata and, in particular, by reliably specifying measurement uncertainties. The overall objective is to ensure the consistency of measurements, especially before and after sensor changes, and to develop the necessary automated procedures to detect breaks caused by instrument changes and to homogenise measurement series. This will ensure that the data remain consistent over long periods of time.Precipitation measurements are affected by several factors that can lead to systematic underestimations. One of these factors is evaporation. This error can be significant, especially for automatic precipitation gauges equipped with a heating system. However, the potentially largest error is triggered by wind. The shape of the funnel influences the wind field around the gauge and small turbulence can occur which can blow snow and small raindrops in particular over the gauge, leading to an underestimation of precipitation.  To minimise this error, primary gauging stations are equipped with a wind shield, while secondary gauging stations are not.These differences can vary from gauge to gauge, leading to inhomogeneities in long series of measurements.  In order to analyse and quantify these and other influences, the German Weather Service has established climate reference stations at ten locations with different natural conditions.
When “Hans” struck Norway: Forecasting, communication and municipal preparedness during an extreme weather event 
Authors: Ødemark Karianne , Verpe Dyrrdal Anita , Mjelstad Håkon
Published: July 2024

Extreme weather events pose significant challenges to communities worldwide, necessitating proactive measures for mitigation and adaptation. We will present a case study of the extreme weather event Hans, which struck Norway with remarkable intensity in August 2023 and led to large-scale flooding and landslides.  Two characteristics set Hans apart from typical extreme rainfall events hitting Norway: 1) its unusual trajectory from the southeast, contrasting with the customary storms from the west, and 2) the large area of heavy rainfall, with return periods exceeding at least 100 years. The event caused heavy rainfall that lasted over several days, thus affecting a widespread area. Through accurate forecasting, successful communication of risks, and well-organized collaboration between key actors, significant societal costs were saved and no lives were lost. We will present the perspectives of the forecasters in the onset of Hans, and on the preparedness efforts undertaken by municipalities in response to the forecasted threat. We will also discuss the value of climate adaptation to such events in an area where extreme precipitation is one of the main direct physical climate risks, including the importance of understanding Hans in a communication and outreach perspective. The event itself is examined by its temporal evolution, spatial distribution, and associated meteorological phenomena. By analyzing observational data,  we can interpret the key atmospheric dynamics driving the extreme weather event, thereby enhancing understanding of its underlying mechanisms. To assess the event’s rarity, we will also present the associated return periods for the observed precipitation amounts.The presentation will highlight our experience from the event, emphasizing the role of communicating forecasts and the forecasters' close collaboration with preparedness and response services, while also highlighting the significance of climate adaptation efforts in regions vulnerable to extreme precipitation.
The cold blue dot - Winter of 2023 - 24 in Scandinavia
Authors: Ødemark Karianne , Gangstø Reidun , Hygen Hans Olav
Published: July 2024

Global temperatures have reached record high levels for 10 months in a row (Copernicus Monthly Climate Bulletin March 2024). At the same time the 2023-2024 cold season in the Nordic region had negative temperature anomalies from October to January, and the region therefore stood out from the rest of the world as a cold blue dot in a red hot world.  A period of 5 days during January with particularly low temperatures, was classified as a severe cold spell by the World Weather Attribution group and therefore an attribution study of the event was performed. The Norwegian Meteorological Institute together with other institutes from the Nordic countries participated in the study. The results showed that the event would have been even colder had it not been for human made climate change. The rarity of the event was also described, which is an important perspective to provide within our climate services. We will present the findings, and will in addition give an overview on the experience from public outreach and communication of this study.  Furthermore, we will present an analysis of the atmospheric characteristics that led to the persistent below normal temperatures in the region for the season overall. During the winter we gained experience on public outreach in a contrasting situation between the cold Nordic region and the rest of the globe.  In addition to low temperatures, several places sat new records for snow depth during the winter. Recurring heavy snowfall events caused difficulties for public transportation systems and also led to school closures. These events got a lot of media attention since a large part of the population was affected, and we will present the researchers work together with the communication department at MET Norway on handling the media attention, as well as our services to municipalities and public transportation companies.  We will highlight our experiences, including how the researchers within the climate services, forecasters and communication group  at MET Norway organized the work on public outreach in cooperation. There will be an emphasis in the presentation on the duality of communicating about a warm world and Europe at the same time as we had a severe cold wave in Scandinavia.
Extensive hydrogeological disruption triggered by an atmospheric river affecting Disko Island (West Greenland) in summer 2023
Authors: Colucci Renato R. , Securo Andrea , Del Gobbo Costanza , Sigsgaard Charlotte , Svennevig Kristian , Citterio Michele
Published: July 2024

Debris flows and slush flows are mass movements that can be triggered abruptly by precipitation and snowmelt. They are a well known contributor to geomorphic changes and potential geohazards in areas such as the subpolar regions. In this study we discuss and analyze a series of mass movements linked to a single event that happened between July 6th and 7th 2023 in Central West Greenland. An atmospheric river led extreme precipitation into Qeqertarsuaq (Disko Island) and surrounding areas, increasing late spring snowmelt runoff significantly and causing hundreds of slush flows and debris flows, which also damaged local infrastructures. We combined remote sensing observations (Sentinel-2 and drone-based) before and after the event to map the larger mass movements. We then used the environmental monitoring dataset available in the area (Greenland Ecosystem Monitoring Disko) and climate reanalysis (Copernicus Arctic Regional Reanalysis) data to assess the synoptic pattern at the base of the event. We found almost 200 significant slush flows and debris flows only in Disko Island. During the 18-hours-event cumulative precipitation peaked 100mm being generally above 80mm in several portions of the island (mainly in the Southwest) where most events occurred. An increase in moisture transport through atmospheric rivers in a warming Arctic, has already been seen as a further contributor to abrupt glacial melting. We show here how such events are able to trigger potential hazards to local communities, making necessary to increase our knowledge about past events and future hazards in remote and less monitored areas, such as Greenland.
Gravity wave observations by (offshore) short-range wind lidars
Authors: Knoop Steven , de Jong Mando , Koning Mariska , Ronda Reinder
Published: July 2024

Short-range vertical profiling wind lidars are extensively used in the context of wind energy. These instruments measure wind profiles up to 200-300 m and their 10-minute averaged wind products are commonly used. Here we discuss their ability to observe atmospheric gravity waves (GW), using the unaveraged data. Trapped GWs in the stable boundary layer that propagate horizontally can result in a strong modulation of wind (and other meteorological variables) with periods similar or smaller than 10 minutes. These periods are such that GWs might be missed in the standard wind lidar data products. In general, the measurements of vertical velocity profiles are the most suitable for GW detection and characterization, while the horizontal wind profiles directly link to the possible impact on wind energy.Here we consider the ZX300M (ZX Lidars) wind lidar, which is operationally deployed on offshore platforms within the Dutch offshore wind farms [1]. The ZX300M is a continuous-wave focusing vertical profiling wind lidar. It measures horizontal wind speed, wind direction and vertical velocity in a range of 10 m to 300 m above the instrument, using velocity azimuth display (VAD) scans of 1 second and a scanning cone angle of 30° (with respect to zenith). Up to 11 heights are measured sequentially.To demonstrate the ability to observe GWs with these instruments we have identified two GW events, in the stable nocturnal boundary layer, during the two-year measurement campaign of the ZX300M wind lidar at our atmospheric supersite Cabauw in 2018-2020 [2]. We compare the unaveraged ZX300M data with in-situ wind measurements in the 213-m tall mast, in particular the vertical velocity as measured by 3D sonic anemometers. We observe a high correlation between the ZX300M wind lidar and in-situ measurements for those GW events. We conclude that the ZX300M nicely captures those GWs, limited by its maximum range of 300 m.Finally, we present our first GW observations from the operational ZX300M instruments within the offshore wind farms. We highlight the GW event on 2022-05-19 observed at platforms Borssele Alpha and Borssele Beta (7 km apart) within offshore wind farm Borssele. Our growing offshore network of wind lidars provided a unique opportunity to detect offshore gravity waves and study their impact on the offshore wind energy.[1] Knoop, S. and de Jong, M.: Wind lidars within Dutch offshore wind farms, EMS 2023, https://doi.org/10.5194/ems2023-271[2] Knoop, S., Bosveld, F. C., de Haij, M. J., and Apituley, A.: A 2-year intercomparison of continuous-wave focusing wind lidar and tall mast wind measurements at Cabauw, Atmos. Meas. Tech., 14, 2219, 2021, https://doi.org/10.5194/amt-14-2219-202
Use of commercial microwave links as scintillometers: potential and limitations towards evaporation estimation
Authors: van der Valk Luuk , Hartogensis Oscar , Coenders-Gerrits Miriam , Hut Rolf , Walraven Bas , Uijlenhoet Remko
Published: July 2024

A scintillometer is a common instrument to measure path-integrated evaporation and sensible heat fluxes. It consists of a transmitter and a receiver separated along a line of sight of several hundreds of meters to a few kilometers. Turbulent eddies and the associated refractive index fluctuations along the path between transmitter and receiver cause diffraction of the transmitted microwave beam (known as the scintillation effect). Scintillometers have been designed to measure the full spectral range of the signal intensity fluctuations caused by this phenomenon and quantitatively link these fluctuations to the turbulent heat fluxes. Commercial Microwave Links (CMLs), such as used in cellular telecommunication networks, also make use of microwave signals. However, CMLs are obviously not designed to capture scintillation fluctuations. We investigate if and under what conditions CMLs can be used to obtain the structure parameter of the refractive index, Cnn, which would be a first step in computing turbulent heat fluxes with CMLs using conventional scintillation theory. To do so, we use data from three collocated microwave links installed over a 856 m path at the Ruisdael Observatory near Cabauw, the Netherlands. We compare received signal intensity fluctuations sampled at 20 Hz from two 38 GHz CMLs formerly employed in telecom networks in the Netherlands, a Nokia Flexihopper and an Ericsson MiniLink, with measurements from a 160 GHz microwave scintillometer (RPG-MWSC) sampled at 1 kHz and an eddy-covariance system. After comparison of the unprocessed Cnn, we reject the Ericsson MiniLink, because its 0.5 dB power quantization was found to be too coarse. Based on power spectra of the Nokia Flexihopper and the microwave scintillometer, we propose two methods to correct for the white noise present in the signal of the Nokia Flexihopper: 1) we apply a high-pass filter and subtract the noise based on a calibration with the microwave scintillometer; 2) we select parts of the power spectra in which the Nokia Flexihopper behaves similar to the microwave scintillometer and correct for the missed part of the scintillation spectrum based on scintillation theory. Calibration on the microwave scintillometer provides the best possible Cnn estimates for the Nokia Flexihopper, although this is usually not feasible for CMLs. Both of our proposed methods show an improvement of Cnn estimates in comparison to unprocessed estimates, though with a larger uncertainty than the reference instruments. Overall, our study illustrates the potential to use CMLs as scintillometers, especially due to their large global coverage, but also lays out major drawbacks, most of which are related to unfavourable design choices made for commercial microwave links.
Improving wind power forecasts in the Belgian North Sea
Authors: Smet Geert , Van den Bleeken Dieter , Van den Bergh Joris , Dehmous Idir , Degrauwe Daan , Van Ginderachter Michiel , Deckmyn Alex
Published: July 2024

With the completion of the first Belgian offshore wind energy zone in 2020, for an installed capacity of 2.26 GW, a significant amount of wind energy is now available in the Belgian part of the North Sea. Due to the relative lack of space in this area, all wind farms lie close together in a narrow band, and each wind farm has a high density, in terms of number of turbines, and/or installed power per area. There are thus considerable wake losses in the Belgian offshore zone. Moreover, in case of a major storm, many wind farms might experience a so called cut-out event, with automatic shut-down of the turbines due to high mean wind speed, at practically the same time. Since this can lead to large imbalance risks on the electricity grid, the Royal Meteorological Institute of Belgium (RMI) has developed a dedicated storm forecast tool for Elia, the Belgian transmission system operator for high-voltage electricity. This storm forecast tool, which has been operational since November 2018, consists of 15 minute wind and power forecasts per wind farm, together with cut-out probabilities and uncertainty quantification, by combining our high-resolution (4km) ALARO model with the ENS ensemble forecasts of the European Centre for Medium Range Weather Forecasting (ECMWF). We report on several approaches to improve the offshore wind power forecasts, as part of the BeFORECAST project (Nov 2022 - Oct 2025), funded by the Energy Transition Fund of the Belgian federal government. In particular, to take into account wake losses, the Fitch et al. wind farm parameterization (WFP) was implemented in our ALARO model, based on an earlier implementation by KNMI into HARMONIE-AROME. Both these models are being developed in the ACCORD consortium, and use the same dynamical core to some extent, with IFS/ARPEGE global codes as basis, but differ greatly in the different physics parameterizations used, and the physics-dynamics coupling (tendencies vs fluxes). For instance, unlike AROME and HARMONIE-AROME, the ALARO model uses an explicit deep convection scheme (3MT) and turbulence is based on the TOUCANS framework. Verification of the improved wind and power forecasts is based on several lidars at different locations, and power data per wind farm from Elia, possibly supplemented with SCADA data from wind farms where available. Other approaches we study are multivariate statistical postprocessing based on historical wind speed observations to generate corrected wind speed scenarios, and postprocessing of forecasts using wake models (since we cannot implement a WFP in the ENS ensemble). Finally, an alternative power forecasting method, using an artificial neural network trained on power observations and NWP forecasts is also looked at. Special consideration is given to wind storms and fast ramping events.
Atmospheric and ocean preconditioning factors of dense shelf water cascading in the NW Mediterranean: insights from reanalyses
Authors: Fos Helena , Peña-Izquierdo Jesús , Amblas David , Estella-Perez Victor , Florindo-Lopez Cristian , Cerdà-Domènech Marc , Calafat Antoni , Corral Sergi , Romero Laia , Sanchez-Vidal Anna
Published: July 2024

The wide continental shelf of the Gulf of Lion in the NW Mediterranean is a region subject to pronounced atmospheric and oceanic interactions. Persistent cold northerly winds trigger progressive cooling of shelf waters, instigating a notable increase in seawater density. This dense water is forced to overflow by the slope, primarily channeled through the submarine canyons and especially through the southernmost Cap de Creus submarine canyon. Known as dense shelf water cascading, this intricate phenomenon exerts a pivotal influence not only on regional oceanographic dynamics but also on seafloor morphology and deep-sea living resources, warranting comprehensive investigation.To understand the interannual variability of cascading events spanning recent decades, we use the Med MFC physical reanalysis dataset, which encompasses the Mediterranean Sea. This dataset has proven invaluable, exhibiting robust correlations with in-situ observations of dense shelf water cascading via moored instrumentation, thereby offering unprecedented insights into the spatiotemporal evolution of water properties and dynamics within the Gulf of Lion.Our study quantifies the influence of the shelf water density modulation by the buoyancy fluxes in the air-sea interface. Leveraging data from atmospheric ERA5 and hydrological GloFAS reanalyses, we unveil a comprehensive understanding of the ocean-atmosphere interaction dynamics within this region. Specifically, we analyze the interannual variability in the buoyancy fluxes calculated from the main forcing agents impacting shelf water density: river freshwater input, wind speed, air-sea temperature contrast, absolute humidity, and precipitation.Our analysis reveals a significant correlation between these fluxes and the East Atlantic pattern (EA), which is one of the main modes of climate variability in the atmosphere. This underscores the intricate interplay between oceanic processes and broader atmospheric dynamics, particularly over the Gulf of Lion. Our findings offer insights into the mechanisms governing dense shelf water cascading and natural variability, thus augmenting our understanding of regional climate dynamics and enhancing predictive capabilities, and help foresee its occurrence and evolution in the context of climate change.
Tailored Weather and Climate Services for Energy Management: Lessons Learned from Introducing a New Energy Bulletin 
Authors: Spirig Christoph , Begert Michael , Isotta Francesco , Posselt Rebekka , Scherrer Simon C. , Schlegel Thomas , Moret Lionel , Croci-Maspoli Mischa
Published: July 2024

Switzerland's current Energy Strategy 2050 pursues two key objectives: Abandoning nuclear power plants in the long term and supporting climate policy that implements measures to achieve the goals of the Paris Climate Change Agreement, which essentially means achieving zero net emissions of greenhouse gases by 2050. The strategy therefore includes the promotion of renewable energies in Switzerland as well as savings and market measures to increase the efficiency of the energy supply. The strong dependence of both the production and consumption of energy on weather means that there is a great need for customized weather and climate information. This need suddenly became urgent in the fall 2022, when the conflict in Ukraine jeopardized the supply of natural gas and, in addition, water reserves were significantly below average after a dry summer, which also jeopardized domestic energy production strongly depending on hydropower.  
In this situation, MeteoSwiss quickly developed a special weekly bulletin for the energy sector providing a detailed picture on past and future heating energy demand. It is based on tools from established climate and temperature forecasting services and tailored to the energy sector by providing monitoring and forecasts in the form of heating degree days (HDD). Expressing both monitoring and sub-seasonal to seasonal forecasts in terms of HDD and relative to climatology proved to be useful identifying energy shortages and taking early action. As there is inevitably considerable uncertainty associated with long-term forecasts, one of the challenges was to convey this uncertainty while still providing actionable information. 

We present the different product elements of the energy bulletin and then discuss our experience in this example of rapid service development in response to an urgent need, covering both technical and organizational aspects.  
Impacts of Thermodynamics Disturbances Induced by Tropical Cyclone on the East Asian Subtropical Westerly Jet
Authors: Wang Tianju , Wang Ju , Huang Hong , Wang Xuezhong , Jiang Chao
Published: July 2024

This research discusses the influence of tropical cyclone (TC) activities in the summer tropical northwest Pacific on the East Asian midlatitude westerly jet through statistical analysis and numerical experiments, and the mechanism is also analyzed.The statistical results indicate that TC activities in the northwest Pacific can induce abnormal westerlies in the midlatitude region of East Asia, and the axis of the westerly jet shifts toward regions with larger anomalous westerlies induced by TCs.Numerical research on the case of TC Maria shows that the thermal effects of the abnormal disturbances near Japan induced by TC activities in the tropical northwest Pacific can result in abnormal temperatures in the midlatitude region of East Asia. Under the constraint of thermal wind relation, the abnormal westerlies form and the position of the westerly jet changes, correspondingly. During this process, the abnormal phase of the P-J teleconnection induced by TC activities plays a major role in causing the subsidence motion in the midlatitude region of East Asia, leading to abnormal changes of the atmospheric temperatures, which affect the meridional temperature gradient in the midlatitude region. Due to the vertical variation of zonal winds and horizontal temperature gradients in the midlatitude region satisfying the thermal wind relationship overall, the zonal winds in the midlatitude region undergo abnormal vertical variations correspondingly, which further changes the position of area with maximum value of the East Asian westerly, and the meridional position of westerly jet axis changes as well.Results of this study demonstrate that TC-induced remote disturbances have thermal effects and can also affect midlatitude systems.
A WISER Approach - co-development of Weather and Climate Information Services across Africa, Asia and the Pacific through the UK Government funded WISER Programme
Authors: Strachan Jane
Published: July 2024

The Weather and Climate Services (WISER) programme delivers transformational change in the quality, accessibility and use of weather and climate information services at local, national, and regional levels. Since its inception in Africa in 2015, WISER has built resilience to the impacts of climate change and supported long term sustainable development for people, communities, and institutions. The WISER programme is funded via the UK government’s Foreign, Commonwealth and Development Office (FCDO) and is managed by the UK Met Office.Between 2015-2021 WISER focused primarily on building weather and climate information services capacity in the East Africa region, with additional focussed activity in the Sahel and since 2022, the WISER programme has expanded in response to other regional weather and climate vulnerabilities. The suite of programmes now includes an expanded footprint in East, West and Southern Africa, the Middle East and North Africa (MENA), and from 2023 it has built on the successes of the Asia Regional Resilience to a Changing Climate (ARRCC) programme to support South Asia, Southeast Asia, and the Pacific Islands.The existing WISER programme builds on the transformational change delivered through previous iterations of WISER and provides an opportunity to replicate, innovate and expand into new areas, build on existing and new regional partnerships, and drawing on lessons learnt and good practice. The activities now aim engage with a wider range of stakeholders to support and improve the uptake and mainstreaming of weather and climate information services into policy, planning and decision making.This presentation will look at the history of the WISER programme, the principles of the WISER approach, particularly It’s approach to gender equality and social inclusion (GESI), and provide examples of WISER projects currently underway.
Building capacity to develop, communicate and use climate information through the H2020 Co-production of Climate Services for East Africa (CONFER) project
Authors: Strachan Jane , Lines Stefan
Published: July 2024

CONFER is an EU-funded research project focusing on climate adaptation through the Co-production of Climate Services for East Africa. The main objective of the project is to co-develop dedicated climate services for the water, energy and food security sectors with stakeholders and end-users, to enhance their ability to plan for and adapt to seasonal climate variability and extremes. This presentation will focus on the training and capacity building component of the project, which aims to build skills and knowledge across a wide range of climate information producers and users. The purpose is to train people in the East Africa region in interpreting and applying climate information and services in a way that benefits and supports resilience against weather and climate variability.Following a user needs analysis, the WMO designated Regional Climate Centre for East Africa, ICPAC (the IGAD Climate Prediction and Application Centre), with support from the Met Office and NORCAP, developed and delivered Synergy Building training workshops targeting a diverse range of participants in ten countries in the region, namely Sudan, South Sudan, Ethiopia, Uganda, Kenya, Tanzania, Djibouti, Somalia, Rwanda, and Burundi, with sessions being held in Uganda, Sudan, Kenya, Djibouti, and Rwanda. The workshops brought together experts and stakeholders from countries based on shared languages to enhance engagement and interaction. Overall, the training workshops empowered 240 participants from different media houses in East Africa, meteorological experts, policymakers, and the private sector, selected by their national institutions. In-person training was delivered alongside online training via a Massive Open Online Course (MOOC) developed by BBC Media Action. The MOOC on ‘climate reporting’ for journalists from vernacular radio and national broadcast media across the region, aimed to bridge the ‘last mile’ gap that exists from NMHSs to the user community.Additional training was also provided to National Meteorological and Hydrological Services (NMHSs) forecasters in the East Africa region via annual “Foundational Seasonal Training”, building capacity on underpinning seasonal forecasting knowledge and techniques. Representatives were then involved in seasonal forecast production at the three annual Greater Horn of Africa Climate Outlook Forums (GHACOFs).CONFER also contributed to the Climate System Analysis Group (CSAG) annual ‘Navigating Climate Risk’ School, a 5-day programme where sector specialists in water and disaster management, agricultural administrators and planners, health workers etc. meet and are trained in how to use climate services effectively, to enable enhanced planning against climate-related risk.
Multi-scale assessment of regional high-resolution reanalyses precipitation fields over Italy
Authors: Cavalleri Francesco , Lussana Cristian , Brunetti Michele , Viterbo Francesca , Bonanno Riccardo , Manara Veronica , Lacavalla Matteo , Maugeri Maurizio
Published: July 2024

Meteorological reanalyses are used for multiple applications, from understanding past climate to assessing extreme weather events. In this study, an extensive validation of high-resolution regional reanalyses was performed, evaluating their capability to reproduce precipitation fields over Italy, which is characterized by complex orography and land-sea interactions.In this study, we carried out an inter-comparison of nine different reanalysis products, using the ECMWF ERA5 product as the global reanalysis reference. Some of the reanalyses considered cover Europe (BOLAM, COSMO-REA6, CERRA), while others are specifically designed for Italy (MERIDA, MERIDA-HRES, MOLOCH, SPHERA, VHR-REA_IT), using a variety of different atmospheric models and parametrizations.The precipitation fields inter-comparison employed wavelet decomposition techniques and frequency distribution analysis. Then, a validation against independent observations involved both observation products interpolated onto regular grids and punctual data from stations’ series.The wavelet decomposition permitted assessing the effective information of every reanalysis at each spatial scale, clustering the products into global, regional, and convection-permitting ones. On the other hand, the frequency distribution of daily rainfall amounts allowed proving the capability of higher-resolution reanalyses to depict the frequency of occurrence of extreme precipitation events better than the ERA5 global product.Moreover, the comparison of the reanalyses fields with observations was performed by calculating the relative bias to assess climatology reliability and the Stable Equitable Error in Probability Space (SEEPS) to evaluate the ability to discriminate among dry, light rain, and heavy rain days. The results indicated wet biases over the Alps, especially during spring and summer, and dry biases over Liguria, Tuscany, the Apennines, and Southern Italy during autumn and winter. Significant differences were found among reanalysis products, with MOLOCH and MERIDA-HRES showing the best performances.Finally, the trend analysis revealed a long-term signal in the reanalysis precipitation bias, with a significant increase in the annual amount in most reanalyses (with the only exception being VHR-REA_IT), suggesting caution when using these products for climate change studies in this area.