bluuebunny/crossref_metadata_2025 huggingface dataset:
Advancing Understanding of the Sea Breeze for the Romanian Black Sea Coast: A Comparative Analysis Using the SBI Index
Authors: Radu Crina , Bandoc Georgeta , Degeratu Mircea
Published: July 2024

The studies on Romanian sea breeze remain relatively underdeveloped, posing a significant gap in climate research. This study aims to utilize the Sea Breeze Index (SBI) to identify cases of sea breeze occurrences along the Romanian coastline. The overarching goal is to enhance our understanding of local climatology and validate the empirical findings through a theoretical approach.The study employs data from the Copernicus European Regional ReAnalysis (CERRA) database, which is available at 3-hour intervals. The first phase of this study is to validate the empirical findings for the year 2018. By utilizing the SBI index, we aim to delineate patterns of sea breezes and their temporal variations throughout the year.Preliminary findings suggest that the theoretical approach based on the SBI index yields results that offer a more robust investigation and constitute a comprehensive exploration of the dynamics of sea breezes along the Romanian coastline. Using the SBI method, sea breeze occurrences have been classified into four distinct types: sea breezes blocked by offshore synoptic flow, sea breeze regime, sea breeze embedded into onshore synoptic current, and sea breeze inhibited by negative thermal gradient. The results revealed a significant increase in the identification of sea breeze cases, compared with the empirical results, with over 70% more instances detected. Notably, over 80% of these cases were found to be associated with incorporated maritime breezes within the synoptic current.By comparing the outcomes of both approaches, we aim to validate the efficacy of the SBI index in identifying and characterizing sea breezes on the Romanian coast. Additionally, the study seeks to elucidate any discrepancies between the two methods, providing insights into the strengths and limitations of each approach. The comparative analysis of theoretical and empirical results will facilitate a more comprehensive understanding of the sea breeze in Romania. Furthermore, it will contribute to the refinement of methodologies for studying and predicting local weather phenomena, thereby enhancing the accuracy of climate models and forecasts.In conclusion, this study highlights the importance of studying sea breezes in Romania and introduces the SBI index as a valuable tool for identifying and analyzing these types of circulation. Through comparative analysis, we demonstrate the applicability and reliability of the SBI index in the Romanian, providing a basis for further research.
No Climate Security Without Collaboration and Social Justice 
Authors: Rantanen Rosa
Published: July 2024

As climate security is an emerging topic in research, civil society and decision-making, it is becoming an inescapable component of transdisciplinary discussions about climate change related risks. While it is important to discuss climate change in the context of security, it is also essential to keep asking questions such as: What do we mean by security? How can we ensure that security is implemented in socially just and environmentally friendly ways? What is the role of meteorologists, and research in general, in supporting truly cross-sectoral collaboration in understanding, mitigating and adapting to climate change related risks?This presentation aims to answer these questions by discussing the wider societal context of meteorological research and some pitfalls of securitazation in the context of climate change, and by providing a practical example of transdisciplinary collaboration. The first ever Climate Security Festival was organized in 2023 in the Finnish Meteorological Institute by the Safer Climate network (based at the Institute for Atmospheric and Earth System Research (INAR), University of Helsinki) and the Committee of 100 in Finland. The transdisciplinary event gathered almost a 100 people together and utilized varying methods, including participatory activities and artistic approaches, to nurture a multifaceted understanding of climate security. The event program was focused around workshops, where people could share information, discuss and experience together in an open, low-hierarchy environment. The overall feedback of the event was very positive and resulted in new connections, experiences and continuing collaborations.Collaboration, citizen engagment and social justice are included in numerous security and climate strategies, guidelines and legislations in local, national and international levels. For implementing these guidelines to raise awareness and mitigate climate related security threats, it is crucial to understand how to build and facilitate transdisciplinary collaborations that nurture learning, understanding and cross-sectoral science-based solutions. This can support us in avoiding polarization and conflicts within transdisciplinary research and the society at large.
Cloud-Resolving Ensemble Prediction of the Extreme Rainfall Event on 2 June 2017 in Northern Taiwan
Authors: Wang Chung-Chieh , Huang Po-Yu , Huang Shin-Yi
Published: July 2024

An extreme Mei-yu rainfall event occurred on 2 June 2017 along the northern coast of Taiwan, where a peak amount of 635 mm fell in about 10 hours from 0100-1100 LST. Using ensemble-based sensivity analysis, an earlier study (Wang et al., 2021) showed that the areal-averaged rainfall in the wider region surrounding northern Taiwan in this event was influenced by frontal moving speed, frontal intensity (contrast), and location and timing of frontal disturbance in experiments using grid sizes of 2.5-5 km, but peak amounts in such runs were no more than 360 mm, suggesting low predictivity for its occurrence. Using 1-km grid size, predictions in a later study (Wang et al., 2023), on the other hand, showed that a peak amount of up to 541 mm can be achieved with a finer grid, but the detailed rainfall pattern and maximum amount are strongly dictated by the presence of a frontal low-pressure disturbance that affected the location and persistence of the surface convergence zone, thus again suggesting high nonlinearity and low predictability. However, in some initial times about 2.5-3 days before the event, the evolutions were more favorable for larger and more concentrated rainfall.In this study, the above extreme rainfall event is further examined, using ensemble forecasts both at 1 km and larger grid sizes, including the experiments carried out in the Taiwan Area Heavy-rainfall Prediction Experiment (TAHPEX). Special attention is given on the predictability of this extreme event and the strategy to produce useful results more effectively with longer lead times for early warning and preparation.
Quasi-biweekly Oscillation of the 2016 Summer Rainfall over the Yangtze Basin in Relation to Intraseasonal Potential Vorticity around the Eastern Tibetan Plateau
Authors: Mao Jiangyu , Zhang Guanshun
Published: July 2024

During the summer of 2016, several heavy rainfall events over the middle and lower reaches of the Yangtze Basin (MLY) were regulated by the 10–20-day quasi-biweekly oscillation (QBWO). The characteristics and mechanisms of the QBWO associated with the MLY rainfall events were examined using ERA-Interim reanalysis data. In addition to the biweekly oscillation in the western North Pacific subtropical high in the lower troposphere, The QBWO of the MLY rainfall was closely linked with upstream intraseasonal potential vorticity (PV) anomalies generated over the eastern slope of the Tibetan Plateau (TP) due to topographic lateral friction. The PV budget analysis demonstrates that the horizontal PV advection and subsequent topographic friction with a four-day phase-lag between them dictated the QBWO of PV anomalies around the eastern TP. The TP-generated PV anomalies then migrate downstream to facilitate the development of the anomalous circulation over the MLY. Importantly,  the strongest of the six heavy rainfall events occurred in the end of June 2016, and it was attributable to a TP Vortex (TPV) in conjunction with a Southwest China Vortex (SWCV). The eastward-moving TPV merged vertically with the SWCV over the eastern Sichuan Basin due to the positive vertical gradient of the TPV-related PV advection, leading the lower-tropospheric jet associated with moisture transport to intensify greatly and converge over the downstream MLY. The merged TPV–SWCV specially facilitated the upper-tropospheric isentropic-gliding ascending motion over the MLY. With the TPV-embedded mid-tropospheric trough migrating continuously eastward, the almost stagnant SWCV was re-separated from the overlying TPV, forming a more eastward-tilted high-PV configuration to trigger stronger ascents including isentropic-gliding, isentropic-displacement, and diabatic heating-related ascending components over the MLY, thus resulting in the most intense rainfall.
Interactions of Atmospheric Chemistry and Atmospheric Boundary Layer: From Megacity to Gigacity
Authors: Ding Aijun
Published: July 2024

The Planetary Boundary Layer (PBL), which influences the dispersion of air pollution and the exchange of heat, water vapour and chemical species between the atmosphere and the surface, plays a very important role in air quality, weather and climate. The diurnal evolution of the PBL is driven by incoming solar radiation, which controls surface fluxes and vertical thermal dynamics. Thus, radiatively important atmospheric chemical species, such as anthropogenic or natural aerosols, which are primarily emitted or secondarily formed from precursors emitted from the surface and further diluted within the PBL, should have strong interactions with the PBL meteorology. This presentation will provide observational and modelling evidence on the interactions between atmospheric chemistry and the atmospheric boundary layer and their impacts on air quality in megacities (Ding et al., 2016) and transboundary air pollution transport between city clusters in the gigacity region of eastern China (Huang et al., 2020), and will present some recent results and insights from intensive field campaigns of chemical and physical parameters and their vertical profiles in eastern China based on a super-tethered airship platform. This presentation will also explore the impact of these interactions on wildfire/agricultural straw burning extreme events in different climate regimes, such as eastern China and the Indo-China peninsula in monsoon Asia, and the west coast of the United States with Mediterranean climate (Ding et al., 2013; Ding et al., 2021; Huang et al., 2023), and discuss the potential implications for chemical weather prediction and climate studies (Huang and Ding, 2021).ReferencesDing, A. et al., Intense atmospheric pollution modifies weather: a case of mixed biomass burning with fossil fuel combustion pollution in eastern China, Chem. Phys., 13, 10545-10554, 2013.Ding, A. et al., Enhanced haze pollution by black carbon in megacities in China, Res. Lett., 43, 2873-2879, 2016.Ding, K. et al., Aerosol-boundary-layer-monsoon interactions amplify semi-direct effect of biomass smoke on low cloud formation in Southeast Asia, Nature Commun. 12, 6416, 2021.Huang, X., Ding, Aerosol as a critical factor causing forecast biases of air temperature in global numerical weather prediction models, Science Bulletin, 66(18), 1917-1924, 2021.Huang, X. et al., Amplified transboundary transport of haze by aerosol–boundary layer interaction in China, Nature Geoscience, 13, 428-434, 2020.Huang, X. et al., Smoke-weather interaction affects extreme wildfires in diverse coastal regions, Science, 379, 457-461, 2023.
Effects of climate change on wild pollinators: the case of butterflies in Central Italy
Authors: Baldi Marina , Biancolini Dino
Published: July 2024

  
Among wild pollinators, diurnal butterflies are important in natural ecosystems and contribute significantly to agricultural productivity. Worryingly, a growing body of literature suggests that climate change (CC) may result in the extinction and decline of many butterfly species1. Understanding which species and areas are most vulnerable to CC is essential for planning conservation and mitigation efforts. The project LIFE project BEEadapt aims to improve pollinator climate resilience in four areas in Central Italy, including protected areas, natural and agro-ecosystems.
The LIFE BEEadapt project focuses on four study areas: the Pontine plain (PP) (Latium), the Roma Natura protected areas (RMPA) (Latium), lowland/hilly areas, the Torricchio Natural Reserve (TNR) (Marche) and the Appennino Tosco-Emiliano National Park (ATENP) with buffer zone (Emilia Romagna), two mountainous areas.
After a preliminary climatological study of the studied areas, authors developed species distribution models (SDMs) using biomod2 R package2, the algorithm Maxent, and two CC scenarios by 2050: sustainable (SSP1-2.6) and fossil-fueled development (SSP5-8.5), to assess the potential impacts of CC on 114 butterflies. Species data was obtained from the Global Biodiversity Information Facility (https://www.gbif.org/) and bioclimatic data from Worldclim (https://www.worldclim.org/) at a resolution of 1 km2. Model performance was assessed using the ROC, and Boyce Index.
Results show first that CC signals are evident in the studied areas. Furthermore, they show that butterflies have a consistent vulnerability pattern at both the species and multispecies level. In the study areas, CC appears to favor lowland and generalist species, which increase their climatic suitability under both scenarios, particularly in mountains. Mountain and specialist species are expected to have reduced climatic suitability, especially under the SSP5-8.5.
Findings are comparable with recent studies on the effects of CC on pollinators, which revealed similar sensitivity patterns based on species ecology, and provide new insights into species potential local responses to CC, allowing to set conservation priorities and direct LIFE BEEadapt mitigation actions. Conservation measures such as habitat restoration and connectivity enhancement will be critical to the long-term survival of these butterfly populations.
Comparison of wind profiles in the operational ICON-D2 analysis with Doppler wind lidar observations in complex topography from the Swabian MOSES 2023 campaign
Authors: Nguyen Duc , Thomas Julia , Gasch Philipp , Oertel Annika
Published: July 2024

High-impact convective events are a common weather phenomenon around the world and can pose significant threats to people and property. However, our understanding of the governing processes of these events still remains incomplete, in particular their initiation and spatio-temporal evolution in regions with complex topography. Systematic validation of the quality of analysis and forecast data over complex terrain is often limited by poor availability of detailed observations. Together, these issues constitute a challenge for understanding and predicting convective events.We aim at contributing to improved forecast quality and process understanding of convective summer-time conditions by leveraging extensive field campaign observations from the KITcube, the mobile atmospheric measurement platform of IMKTRO at KIT. To achieve this, we focus on the 'Swabian MOSES campaign' which took place in the Black Forest region, Germany, during the summer 2023 and provides, among others, observations from a large network of 12 Doppler wind lidars. From each Doppler wind lidar, we retrieve vertical profiles of the wind speed and direction. These observations of the dynamic structure of the lower troposphere are used to characterize the mesoscale (pre-)convective environment and are compared to the operational high-resolution analysis data of the German Weather Service. The three months of observations provide a comprehensive independent data set for the validation of the analysis data across the Black Forest. We present initial results from the field campaign, emphasizing convective conditions, and illustrate the comparison between high-resolution analysis and campaign observations for vertical profiles of wind speed and direction. First results show that the analysis bias differs between different sites, and at different altitudes, with a larger bias in the lowest 2 km. The comparison further reveals that the zonal component of the wind more strongly contributes to the bias. The campaign observations facilitate a better understanding of the complex interactions between the terrain and the overlying atmospheric processes as well as the evaluation of the performance and limitations of a convective-scale numerical weather prediction system.
“Weather forecasting” of indoor air temperatures in Amsterdam (The Netherlands) to facilitate early heat warnings.
Authors: Maas Arthur , Peerlings Esther , Steeneveld Gert-Jan
Published: July 2024

The ongoing climate change results in increasing frequency of warm episodes and heat waves. While a lot of studies focuses on understanding and predicting outdoor air temperature and human comfort, less is known about indoor temperatures that are reached during these warm episodes. This is surprising since people generally spend the majority of their time indoors, e.g. at work or in their living or bed room. This study develops and evaluates a relatively simple forecasting system that aims to make five day forecasts for real world room temperatures. The system builds upon a relatively simple physical-statistical model for the heat budget of a room that is forced by outdoor weather variables like solar radiation, wind speed, air temperature. In addition, room temperature observations from ~60 houses in Amsterdam are used to train this physical-statistical model. After training the calibrated model is used for forecasting and driven by ECMWF operational forecasts of outdoor meteorological variables for the city of Amsterdam (The Netherlands) for the summer of 2023. Room temperatures are initialized daily by room temperature observations from these ~60 houses. We evaluate the forecasting system on the summer of 2023. We find the model system is well to produce a meaningful room temperature forecast for most of the houses. Forecasts for the daily mean temperature of the living room outperforms the forecast for the daily mean bed room temperatures. The median RMSE (over all 60 houses) for the living room forecast increases from 0.38 K for the one-day forecast to 0.95 K for the five-day forecast. Forecasts for daily mean temperatures are better than for daily maximum temperatures. With this forecast tool we aim to study whether citizens adapt their behaviour in protecting their homes from indoor heat when they receive the forecast information.
Sea-effect snowfall in Finland in 1998-2018 based on convection-permitting climate model data
Authors: Virman Meri , Jylhä Kirsti , Olsson Taru
Published: July 2024

Sea-effect snowfall can occur when cold air moves over a relatively warm and ice-free sea. When intense sea-effect snowfall systems move over land, they can cause considerable damage to infrastructure and disrupt traffic. Sea-effect snowfall is a common phenomenon in Finland, but its spatial and temporal distribution has only recently been studied using a detection method on atmospheric reanalysis data and snow depth observations. 

In this study, we refine the previously used detection method and apply it to convection-permitting regional climate model data. The data has been made with the HARMONIE-Climate (HCLIM) model with a spatial resolution of 3 km for the years 1998-2018. The data has been produced by the Nordic Convection Permitting Climate Projections project (NorCP) group.  

The motivation is two-fold. First, we investigate whether HCLIM can simulate the sea-effect snowfall in Finland realistically and be used in studies of sea-effect snowfall in the past and future. Second, using the high-resolution dataset with non-hydrostatic dynamics, we aim to gain more detailed understanding of the spatial and temporal distribution of sea-effect snowfall in Finland, compared to studies based on coarser data. 

The detection method is based on finding the times and grid boxes with, first, considerable amounts of snowfall and, second, environmental conditions shown in previous literature to favour the occurrence of sea-effect snowfall systems. In this work, we present the spatial and temporal distribution of sea-effect snowfall cases in Finland based on the HCLIM data and show that the annual and monthly mean distributions of sea-effect snowfall days in HCLIM were qualitatively similar to the previously defined climatology. In the future, we plan to use the climate model to study how the sea-effect snowfall climatology in Finland may change due to climate change. 
How observational empowering is brought into action in South Sudan: GeoSphere Austria’s activities under the WMO Systematic Observation Financing Facility umbrella 
Authors: Arnold Arias Delia , Gershtein Giora , Wotawa Gerhard , Senoner Wolfgang , Krieger Veronika , Schaffhauser Andreas
Published: July 2024

Climate change is already causing havoc, especially in vulnerable regions, where every minute and every action counts.  During 2021 COP26, WMO, UNDP, UNEP joined efforts and established the Systematic Observations Financial Facility (SOFF) as a new focused UN financing mechanism to foster climate action through the development of sustained and sustainable observational networks. While observations are the critical component in the weather information value chain supporting informed weather and climate-based decisions, they are often addressed project-based and under a limited in time funding approach.  SOFF brings together the national weather service, a peer advisor from a pool of National Hydrological and Meteorological Services worldwide and an implementing entity, one of the Members of the Hydromet Alliance, to make sustained weather observations a long-term reality.  SOFF builds on the 2019’s Global Basics Observation Network (GBON) establishment by the 193 members states and territories of WMO. GBON defines the requirements for data collection and international sharing to provide the essential data needs for global and regional weather and climate models. However, although the requirements are set, GBON is not yet widespread achieved. This is particularly relevant in Small Island Developing States (SIDS) and Least Developed Countries (LDCs), therefore becoming the initial target countries for the SOFF venture.Sharing expertise to support the global meteorological community is an important part of GeoSphere Austria's core mission. Austria has supported the SOFF initiative since its inception.  In a joint approach with four implementing entities, GeoSphere Austria is peer-advising 8 countries worldwide and defining their path towards GBON compliance with a sustainable approach. The work of GeoSphere Austria is based on the analysis of the current situation in the countries. It then focuses on the value chain as the backbone for shaping the national development plan, while building a long-term commitment that enables shared growth as national weather services.This work shows the overall approach, best practices and lessons learnt from GeoSphere Austria’s international cooperation under SOFF and provides a walk-through of the activities performed. The steps that include on-site assessment, the design of a national contribution plan and the initiation of its implementation plan, are shown based on a SOFF front-runner country, South Sudan.
Towards a transparent and reproducible evaluation framework of commercial solar forecasting solutions
Authors: Yezeguelian Loïc , Carrière Thomas , Pitaval Sébastien , Rodriguez Benjamin , Saint-Drenan Yves-Marie , Ménard Lionel
Published: July 2024

With the current and expected development of the installed solar capacity, solar forecasting is becoming a crucial part of the electricity supply system to allow an optimal integration of the weather dependent power production. A growing number of algorithms and forecast providers has appeared in the academic and industrial scenes to address this need.The multitude of forecast solutions is beneficial for the industry because it ultimately results in an increase the forecast accuracy. But at the same time, it makes it difficult for forecast users to have a clear view on the strengths and weaknesses of the different solutions. This lack of clarity is reinforced by the use of different evaluation methodologies and proprietary reference solar measurements.This work aims at contributing to the establishment of a standard for solar forecast evaluation based on backtest simulations (also known as hindcasts). The cornerstone of our proposed methodology is to base the forecast evaluation on open-data and FAIR in-situ measurements so that the evaluation is reproducible. Furthermore, we propose to share our evaluation methodology so that any deviation resulting from the data preparation, quality control, filtering or selected baseline are avoided. Finally, we propose in addition to standard error metrics (MAE, RMSE, bias…) a set of evaluation procedures aimed to inform end-users on the main characteristics of a forecast:Performance of the forecast in specific weather conditions (cloud free, overcast, variable conditions, regime change) following the approach suggested in Verbois et al. (2020)
Comparison of the variability of the forecasted solar irradiance and the reference solar irradiance measurements
Performance of ramp detections (sharpness of ramps, time lag) based on the work of Vallance et al. (2018)
…
The numerical, visual or behavioral performance of a particular model against these procedures will be systematically compared with results obtained similarly on typical baseline forecast models (such as persistence, NWP only or CMV forecasts).The current work is limited to deterministic forecast but an extension to probabilistic forecast is planned in the very near future. Verbois, H., Blanc, P., Huva, R., Saint-Drenan, Y.-M., Rusydi, A., Thiery, A., Beyond quadratic error: Case-study of a multiple criteria approach to the performance assessment of numerical forecasts of solar irradiance in the tropics, Renewable and Sustainable Energy Reviews, Volume 117, 2020, 109471, ISSN 1364-0321, https://doi.org/10.1016/j.rser.2019.109471.Vallance, L., Charbonnier, B., Paul, N., Dubost, S., Blanc, P. Towards a standardized procedure to assess solar forecast accuracy: A new ramp and time alignment metric. Solar Energy, 2017, 150, pp.408 - 422. ⟨10.1016/j.solener.2017.04.064⟩. ⟨hal-01522453⟩
Quantifying double-penalty effects and mitigating their impact on forecast verification
Authors: Lledó Llorenç , Skok Gregor , Haiden Thomas
Published: July 2024

Location errors in precipitation forecasts are ubiquitous in high-resolution weather forecasts due to the misplacement of convective cells but also of mesoscale or synoptic-scale features such as convergence lines or low-pressure systems. However, those kinds of forecast errors never appear in isolation and are usually mixed with intensity errors and more generally with systematic model biases. Therefore, correctly disentangling the contribution of location errors in verification scores is challenging, but also essential to advance forecast quality due to a couple of reasons. Firstly, location errors will incur a double penalty in traditional point-by-point verification (one false alarm event and one missed event). As a result, traditional metrics have the undesirable property of penalizing more a forecast with a correct feature in the wrong location than a forecast that misses the feature. In second place, once a forecast has a location error, traditional metrics are insensitive to the magnitude of the displacement. Hence, traditional metrics are not good at detecting improvements in the size of location errors (i.e. they lack discrimination). Both problems imply that intrinsically better forecasts do not necessarily get better scores. Here we showcase some novel ways to tackle those two issues from different perspectives. Regarding the first issue, we present a new decomposition of the Mean Squared Error into three positive definite terms, one of which is linked to the amount of double penalty. Then we show how this allows screening forecasts for their levels of double penalty.Regarding the second issue, recent advances in spatial verification techniques have enabled estimating location errors of global precipitation forecasts by approximating the Wasserstein distance between unbiased fields. This technique constructs a transport plan to move all the precipitation water in the forecasts to the correct locations according to observations, from which a mean location error is computed. We have extended this technique to be able to work with biased fields and at the same time curtail the location errors to prevent large displacement errors that result from biases in regions far away. This enables us to detect improvements at global or regional scale in ECMWF forecasts.Finally, we have also shown that there is a relationship between the travel plan employed to compute the mean location error and the Mean Absolute Error. This allows us to go back to the first issue again and assess what proportion of MAE is contributed by location errors of a certain scale.
A warning value chain Assessment for Typhoon Muifa (2022) 
Authors: Wang Qian , Wang Yi , Dai Kan , Yang Kun , Xiang Chunyi
Published: July 2024

Typhoon Muifa (2022) is the strongest landfalling typhoon over China in 2022, causing long-lasting and widespread wind and rainfall in East and Northeast China. Using the end-to-end warning value chain method, this paper carried out the evaluations on the warning chain including observation, weather forecast, hazard forecast, impact forecasts, warning communication and warning response for this case. The “bridges” between each part are comprehensively analyzed based on the expert scores. In the four times of landfall events, monitoring, forecasting and early warning in the field of meteorology is relatively done well. The medium- to long-term track forecast in the early stage of Muifa’s lifetime is a great challenge in the track forecast, and the deviation between the numerical model outputs and observations in the long-term forecast of the main impact weather systems is obvious, timely inspection and correction of the model results is very important for the warning preparing. Under the scenario of binary typhoons or multi-vortex, the dispersion of the ensemble forecast is large. Intensity and position differences of the cyclone on the east side have a significant impact on the track of Muifa. The along-track error in the process of extratropical transition after landfall is the primary source of large track forecast errors, especially reduced the effectiveness of early warnings. It is also found out the weakest link among the chain is the impact forecast, with deficiencies in impact data sharing among different ministries and accurate high-resolution modeling in social, economic and health fields. Under the national disaster prevention and mitigation framework, meteorological departments have established effective warning releasing system for the decision-makers. Timely warnings have been delivered at different government levels and there is zero casualties for this case. Attention should be paid to the analysis of extreme tropical cyclone disasters and their trends in the context of climate change, as well as the refinement and development of impact forecasting and risk warning product.This assessement of the warning value chain provide a good example for other meteorological service to conduct similar analysis of their own warning chains.
Variability of combined extreme climate indices over the Mediterranean region under Different Emission Scenarios.
Authors: Polychroni Iliana , Hatzaki Maria , Nastos Panagiotis
Published: July 2024

According to the latest IPCC report (2023), the Mediterranean region faces already significant risks like heatwaves, water scarcity, droughts, coastal risks due to flooding, erosion, wildfires and human health due to climate change. Taking into consideration that the Mediterranean region experiences air temperature almost 1.5 ºC above the pre-industrial level, it is obvious that the temperature extremes are likely to continue to increase more than the global average and since the precipitation is decreasing, droughts will be more frequent and intense.In this work, the spatial and temporal variability of four combined extreme climate indices over the Mediterranean region is investigated under the aspect of the upcoming climate change. More specifically, these combined extremes indices concern Cold/Dry (CD), Cold/Wet (CW), Warm/Dry (WD) and Warm/Wet (WW) days and they are defined by the exceedances of the joint modes of air temperature and precipitation using the 25th and 75th percentile levels (European Climate Assessment &Dataset, www.ecad.eu).The data used for the calculations of the indices concern daily mean temperature and precipitation datasets from an ensemble of 8 regional climate models (RCMs) simulations for the European domain (EURO-CORDEX) with a spatial resolution of 0.11 degree (EUR-11, ~12.5km).  All the calculations and the visualizations of the maps have been conducted in R project.These extreme indices were calculated seasonally and annually for the periods 2041-2060 (near future) and 2081-2100 (far future), with reference period 1981-2005 for the percentiles, under the RCP2.6, RCP4.5 and RCP8.5 emission scenarios. In addition, seasonal and annual means and trends were estimated for each index for the near future and far future, under all the aforementioned emission scenarios. The findings revealed an increased frequency of WD days in almost all the Mediterranean region and high values of CD days in many areas, against few WW and CW days.
How do convective cold pools influence the stability and turbulence conditions near wind turbines in Northern Germany?
Authors: Thayer Jeffrey , Kilroy Gerard , Wildmann Norman , Englberger Antonia
Published: July 2024

Convective cold pools routinely pass over the dense network of wind turbines in northern Germany, causing short-term changes in boundary-layer wind speeds (i.e., wind ramp events) and atmospheric stability. These large, rapid, and more-localized variations in the low-level kinematic and thermodynamic structure are difficult for numerical weather prediction models to forecast with sufficient spatial and temporal accuracy for utilization by wind turbine operators. As boundary-layer stability and winds strongly influence wind turbine structural loads, downstream turbulent wake behavior, and power generation, it is important to better understand how rapid changes in dynamic processes evolve within the vertical layer of wind turbine rotor blades (~50 - 150 meters altitude).Using in-situ observations and high-resolution modeling focused on the WiValdi research wind park in Krummendeich, Germany, we examine how convective cold pool passages from 2020-2023 impact the inflow and turbulent wakes for two installed turbines with a hub height of 92 meters. Meteorological mast, Doppler wind lidar, and microwave radiometer observations provide upstream and downstream measurements of stability, vertical shear, and turbulence variations at ~1-minute resolution. While this measurement coverage adequately captures the cold pool evolution relative to each turbine, we remain somewhat limited by the fixed instrument locations for measuring upstream conditions and the three-dimensional turbulent wake structure. Therefore, we also utilize the mesoscale model WRF in large-eddy-simulation mode, with inserted generalized actuator disks acting as proxy wind turbines, to analyze far-upstream inflow conditions and three-dimensional wake characteristics during cold pool passages. The proposed work provides a foundation for future analysis which will more robustly verify WRF output using additional WiValdi observations.
Impact of tropical cyclones over the eastern North Pacific on El Niño–Southern Oscillation intensity
Authors: Wang Qiuyun , Tan Zhe-Min
Published: July 2024

Most tropical cyclones (TCs) generated over the eastern North Pacific (ENP) do not make landfall. Consequently, TCs in this basin have received less attention, especially those that occur away from the mainland. Furthermore, there have been few studies of the climatic effects of ENP TCs. This study explores the feedback relationship between ENP TCs and the intensity of the El Niño–Southern Oscillation (ENSO), including El Niño and La Niña events, from the perspective of accumulated cyclone energy (ACE). Observational and modeling results indicate that the ENP ACE 3 months earlier can still affect the intensity of El Niño and La Niña events, although the SST persistence is main contributor. Thereinto, the impact of ENP TCs on El Niño appears to be approximately equal to that on La Niña. Moreover, this impact is independent of the persistence of the sea surface temperature (SST) in the Niño 3.4 region and the Madden–Julian Oscillation. Generally, the greater the ENP ACE, the stronger the El Niño, and the smaller the ENP ACE, the stronger the La Niña, this is especially the case for those TCs that develop over the July‒September period. In addition, results show that the ENP TCs modulate ENSO intensity by changing anomalous zonal wind at the low-level atmospheric layer. And the joint impacts of the low-level zonal wind anomalies on the Walker circulation and the east-west thermocline gradient lead to the time characteristics that ENP TCs lead ENSO intensity by about 3 months. This study proposes a cross-time-scale role for tropical cyclones in the development of ENSO, further expanding the theoretical framework for ENSO's development, and offering significant scientific relevance and practical value for its prediction.
Urban Heat Assessment, and Heat Risk Identification in Taiwan’s Built Environment.
Authors: Yu Si-Yu , Lin Tzu-Ping
Published: July 2024

The temperature in Taiwan is expected to continue to rise in the future based on the worst-case scenario of global warming (SSP5-8.5). And the average annual temperature in the middle /end of the 21st century may rise by more than 1.8 ℃/ 3.4 ℃; and the number of days with high temperatures above 36 ℃ will increase in various places. Under the worst scenario (SSP5-8.5), in the middle/ late 21st century, the increase will be approximately 8.5 days/ 48.1 days, with the increase in urban areas being more significant than in other areas. In the future, the summer period will extend from the current approximately 130 days to 155-210 days, and the winter period will decrease from the current approximately 70 days to 0-50 days. Taiwan will face more severe conditions in the future.Although Taiwan has gradually begun to address climate change and urban high temperature issues, there are no specific urban high temperature implementations and regulations, and there is a lack of tools and mechanisms to effectively quantify or assess urban high temperature risks. Since Taiwan does not have exclusive regulations on high temperature response, extreme high temperature has been viewed as one of the natural disasters, such as typhoons, earthquakes, droughts, etc. Which is highly dependent on the disaster prevention and response capabilities of individual local governments. The implementation process is different in different counties and cities, and the results cannot be reviewed uniformly. Moreover, there are differences between cities and counties, with different problems, geographical environments, social vulnerability, etc., making it difficult to compare the risks of high temperatures and share experiences.The urban built environment is critical to outdoor thermal comfort and heat stress risks. Case studies of several outdoor activities of different scales show that under different environmental conditions, participants of different identities will have different thermal risks and different thermal perception/behavior patterns. After understanding the impact of outdoor thermal comfort and related differences in feelings and behaviors, we can further analyze the impact of outdoor high temperatures on the "built environment" and "social vulnerability".
Monitoring and Forecasting wet-snowfall and snow sleeves accretion on overhead power lines in the Italian western Alps 
Authors: Vitali Bruno , Bonanno Riccardo , Lacavalla Matteo
Published: July 2024

Heavy wet snowfall events are responsible for several and harmful winter blackouts on Italian power networks due to the formation of cylindrical snow sleeves on overhead line conductors and shield wires. Despite field observations and modelling studies in the last decades, accurately forecasting these events remains challenging because of the peculiar local meteorological conditions. Although the total number of snowfall events decreased over the alpine region during the last 20 years, last winter season (2023-2024) witnessed several significant wet snowfall events, characterized by mixed convective-advective precipitation, causing several power disruptions, and underscoring the persistent threat posed by this atmospheric phenomenon.The current research activity carried out in RSE involves monitoring systems of sleeve formations at the Wet-snow Ice Laboratory Detection (WILD) station in the south-western Alps, a historical reconstruction of wet snow loads through the MEteorological Reanalysis Italian Dataset (MERIDA), and an operational forecast system Wet-snow Overload aLert and Forecasting (WOLF) for the identification of weather conditions favorable to the formation of snow sleeves on the overhead conductors.WOLF consists of: a) a version of the Weather Research and Forecasting (WRF) model at 4 km spatial resolution properly configured to optimize the description of temperature and precipitation, variables primarily involved in the identification of wet snow and in the modelling of snow sleeves accretion b) an identification method for wet snow conditions, either considering a “thermal window” or the “snow ratio” of precipitation, and c) a sleeve accretion model (Makkonen model for wet-snow, ISO 12494:2017).This study presents some exemplary case studies from the 2023-2024 winter season to highlight current challenges of wet snowfall prediction. High resolution simulations (1 km) were carried out for an accurate description of the mountainous area of south-western Alps where the WILD station is located. Different model drivers (IFS and GFS), model resolutions and wet-snow identification methods were evaluated against meteorological and snow mass measurements collected at the WILD station.Preliminary results showed that the snow load forecast accuracy is primarily related to the choice of the model driver and, secondarily, to the wet snow identification method. The analyzed case studies are particularly challenging because of mixed convective-advective characteristic and because of complex orography. Additional case studies should be investigated to further assess the relative skill of meteorological drivers and of wet-snow identification methods for the snow load forecast in the WOLF system and in high resolution simulation focusing on the WILD station.
Towards unified land data assimilation at ECMWF: Soil and snow temperature analysis in the Simplified Extended Kalman Filter
Authors: Herbert Christoph , de Rosnay Patricia , Weston Peter , Fairbairn David
Published: July 2024

Numerical weather prediction requires well-defined initial conditions at the interface between land and atmosphere. Weather centres such as the European Centre for Medium-Range Weather Forecasts (ECMWF) currently rely on a variety of data assimilation schemes to analyze different land variables in their operational forecast system. Recent activities at ECMWF are towards a unified and more consistent land data assimilation system that can provide more accurate initial conditions for the atmospheric forecast. The first step is to replace the current 1D Optimal Interpolation (1D-OI) so far used for single-layer soil and snow temperature analyses and integrate these variables into the most advanced ensemble-based Simplified Extended Kalman Filter (SEKF) applied in operations for multi-layer soil moisture analysis. The focus is on the technical developments to integrate the first-layer snow and multi-layer soil temperature into the SEKF control vector and on the evaluation of the new implementation with respect to the impact on the atmospheric forecast skill. A sensitivity analysis regarding Jacobians computed from the covariances between screen-level 2-metre temperature observation and soil and snow temperature reveals better representation of small-scale features associated to land heterogeneity when compared to the empirically obtained sensitivity used in the 1D-OI. A series of NWP experiments were conducted over a three-month summer and winter period to test the benefit of several configurations of the SEKF. Compared to the 1D-OI, the SEKF leads to significant improvements in the 2-metre temperature forecast with seasonal differences in the verification against own analyses and to slightly improved results in the validation using independent synoptic observations. The work presented will lay the foundation for further developments including the integration of additional land variables, such as snow depth and vegetation-related variables, into the SEKF and the investigation of quasi-strong land-atmosphere coupling.
The Norwegian State of the Climate Event
Authors: Gangstø Reidun , Velle Magne , Hygen Hans Olav
Published: July 2024

The Norwegian State of the Climate Event, annually led by the Norwegian Meteorological Institute, has transformed significantly  over the past 12 years. Originally a gathering reserved for collaborating institutes and, eventually, the press, it has evolved into a substantial public forum aimed at raising awareness about climate change and its societal impacts.At the event, we provide updates on the global and national state of the climate, offering perspectives on where we are heading. Through presentations by meteorologists and climate researchers, attendees gain insights into climate patterns from the previous year, framed within a broader climatic context. We also spotlight various topics within climate change research that are pertinent to the preceding year or are current areas of investigation. This way, the event emphasizes the authority of the Norwegian Meteorological Institute regarding climate change and our trajectory. The primary audience for the event comprises decision-makers who need insights into preparing for the increasing frequency and severity of extreme weather events in Norway caused by climate change. Furthermore, the event's practice of inviting guest speakers from diverse institutes underscores the importance of interdisciplinary collaboration in tackling the mounting challenges posed by climate change. Over the years, the event's format has grown and become more professional, attracting the attention of researchers, decision-makers, the media, and the general public. Thanks to the active involvement of the communication department, the content has been expertly crafted to visually engage the audience, ensuring that the event's message reaches a broader audience and leaves a more profound impact. Media is also an important target audience, and the event receives good press coverage.Last year, the event achieved new heights by hosting at the Ministry of Climate and Environment, with the opening address delivered by the minister. The event was broadcast online to a record-high number of viewers, and its content was widely disseminated across various social media platforms.This narrative traces the evolution of the event from its modest origins to a multifaceted, influential endeavor that resonates with experts, politicians, and the broader public alike.