OSA1.2 | Warning value chains and early warning systems
Warning value chains and early warning systems
Conveners: Elizabeth Ebert, Robert Neal, David Hoffmann
Orals
| Wed, 04 Sep, 14:00–15:30 (CEST)
 
Lecture room B5
Posters
| Attendance Wed, 04 Sep, 18:00–19:30 (CEST) | Display Wed, 04 Sep, 08:00–Thu, 05 Sep, 13:00|Poster area 'Galaria Paranimf'
Orals |
Wed, 14:00
Posters
Wed, 18:00
Successful warnings require information and expertise to be integrated across a multitude of domains including environmental observation, weather/climate and hazard modelling, impact prediction, warning communication and decision making. This comes with many challenges including building effective partnerships between the different players involved in the warning process who may have different expectations about the spatio-temporal detail of the warning, different needs for uncertainty information, different abilities to handle missing information, and so on.

The value chain (or the value cycle or network) provides a useful framework for describing and understanding the many different groups, skills, tools, relationships, and data/information flows that combine to produce and deliver warnings. It can characterise who does what and how groups interact and exchange data and information to provide critical services during a warning situation (information flow mainly "down the chain"). It can also support the co-design, co-creation and co-provision of services during the service development phase (user needs propagated "up the chain"). The effectiveness of the value chain may be measured using different, yet complementary, methods and metrics that emphasise different characteristics of the value chain such as accuracy, timeliness, relevance, and socioeconomic outcomes.

Case studies of existing warning chains and high impact events can apply value chain approaches to characterise and measure the effectiveness of the tools, processes, partnerships, and infrastructure. This provides the evidence to identify shortfalls and propose investments in new capability and partnerships.

This session welcomes contributions on:
• Assessments of high-impact case study events using value chain approaches
• Challenges, gaps and opportunities arising from using value chains
• Value chain approaches, metrics and measures
• Warning system approaches covering a range of time-scales

Orals: Wed, 4 Sep | Lecture room B5

Chairpersons: Elizabeth Ebert, Robert Neal, David Hoffmann
Warning value chains and early warning systems
14:00–14:15
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EMS2024-1022
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Onsite presentation
Looking backwards and looking forwards:  outcomes and prospects for the WMO WWRP Value Chain Project 
David Hoffmann, Beth Ebert, and Carla Mooney

The Value Chain Project is a 4-year initiative under the WMO World Weather Research Programme (WWRP). The Project aims to review value chain practices used to describe and understand weather, warning and climate services; assess and provide guidance on how to effectively apply value chains in a weather warning context involving multiple uses and partnerships; and create a searchable warning database that researchers and practitioners can use to explore the organisation and performance of actual end-to-end warning chains for high impact events, and assess their effectiveness using value chain approaches.  

The anticipated benefits from the project were manifold and included providing National Meteorological and Hydrological Services (NMHS) and private weather and climate providers with resources, tools and knowledge to be able to apply the value chain to measure and improve the effectiveness of their early warning systems.  

The value chain concept is useful for understanding the strengths and weakness of existing services, decision making about investment in improvements and the design of new warning systems. The Framework, which is a key output from the project, provides a multi-faceted guide for NMHS in developed and developing countries to combine social and physical sciences to enhance early warning systems.  

The value chain questionnaire, developed as part of the project, allows a forensic end-to-end evaluation of high-impact weather events to assess the performance of warning systems for a specific weather event.  It can be adopted by any NMHS to assess their services, as done by the UK Met Office.  

The growing collection of case studies (that will be stored in an accessible searchable online database) will give visibility to best practice in successful early warning systems and lessons learnt from high impact weather events.  The opportunity for doing cross-case analyses of countries, hazard types and early warning systems will facilitate access to insights on the elements of effective early warning systems in different contexts.  

The project has explored the value chain both as a way of thinking and as a methodology. The collaboration of the 40-member interdisciplinary project team from academia, public and private weather providers across a range of activities has contributed significantly to its impact. The involvement and contribution of this group has extended the reach of the project and created novel learning opportunities and interactions. The resources and tools developed through the project will support more systematic and rigorous decision making and by extension the capacity of NMHS to improve the social and economic value of the services they provide. 

This presentation will summarise the project’s achievements over the past four years and outline ongoing applications of the project’s deliverables. 

How to cite: Hoffmann, D., Ebert, B., and Mooney, C.: Looking backwards and looking forwards:  outcomes and prospects for the WMO WWRP Value Chain Project, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-1022, https://doi.org/10.5194/ems2024-1022, 2024.

14:15–14:30
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EMS2024-235
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Onsite presentation
Value added by hazard impact modelling within the warning value chain for three impactful surface water flooding events in 2022 
Robert Neal, Joanne Robbins, John Mooney, Katie Egan, and Julia Perez

The warning value chain is a concept whereby the process of producing a warning is represented by a chain of sources of expertise (components), connected by bridges that convey bidirectional information exchanges. An associated warning value chain questionnaire – produced by the WMO’s High Impact Weather (HIWeather) Warning Value Chain Flagship Project – has been used to carry out a warning value chain assessment for three surface water flooding (SWF) events in the UK. These events occurred during the summer and autumn of 2022 and involved localised convection leading to predominantly minor SWF impacts. Forecast confidence was very low for all events resulting in some short-lead time and responsive warnings. This talk will briefly describe these events before focusing on the value added to the warnings by the Surface Water Flooding Hazard Impact Model (SWFHIM). SWFHIM is an operational forecasting tool used by the Flood Forecasting Centre (a partnership between the Met Office and Environment Agency) to objectively assess the likelihood of SWF impacts across England and Wales, which ultimately feeds into the decision-making process for issuing warnings. The SWFHIM adds value to the weather and hazard outputs by deriving probabilities of impacts using a range of post-processing and forecast presentation methods. However, results from the warning value chain questionnaire helped to identify improvements that may enhance future warnings. For example, SWFHIM forecast presentation changes may improve the pull-through and interpretation of information. Also, recent enhancements to the configuration of the driving convective-scale ensemble are not yet being fully utilized by the hazard-impact modelling. These points and more will be discussed in this talk. 

How to cite: Neal, R., Robbins, J., Mooney, J., Egan, K., and Perez, J.: Value added by hazard impact modelling within the warning value chain for three impactful surface water flooding events in 2022, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-235, https://doi.org/10.5194/ems2024-235, 2024.

14:30–14:45
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EMS2024-501
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Onsite presentation
A warning value chain Assessment for Typhoon Muifa (2022)  
Qian Wang, Yi Wang, Kan Dai, Kun Yang, and Chunyi Xiang

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.

How to cite: Wang, Q., Wang, Y., Dai, K., Yang, K., and Xiang, C.: A warning value chain Assessment for Typhoon Muifa (2022) , EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-501, https://doi.org/10.5194/ems2024-501, 2024.

14:45–15:00
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EMS2024-631
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Onsite presentation
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Using a value chain to develop a new warning service from scratch - epidemic thunderstorm asthma risk forecasts in Victoria, Australia 
Elizabeth Ebert, Danny Csutoros, Jim Black, Edwin R. Lampugnani, Usha Nattala, and Edward Newbigin

In November 2016, an unprecedented epidemic thunderstorm asthma event in Victoria, Australia, resulted in many thousands of people developing breathing difficulties in a very short period of time. It caused ten deaths and created extreme demand across the Victorian health and emergency services. Because of the link between thunderstorm asthma and grass pollen allergies, a new early warning system for epidemic thunderstorm asthma (ETSA) risk was developed and operates during grass pollen season (October-December) each year. The warnings are delivered through a partnership between the Victorian Department of Health, the Bureau of Meteorology, the University of Melbourne, and AirHealth Lab.

Value chain concepts were instrumental in the design of the warnings. Starting with the user needs, namely health sector preparedness and community safety, the partners worked backwards to determine the value chain of necessary capabilities (communication, risk assessment, hazard prediction, modelling, observations) and information flows that would be needed to provide a thunderstorm asthma warning service. This process highlighted gaps in knowledge of the hazard, and the need to develop capability to measure and predict grass pollen to support the thunderstorm asthma warnings. The value chain also helped define the partners’ roles and responsibilities in delivering the warnings.

Focused effort by the partners enabled the thunderstorm asthma warning system to be implemented in time for the 2017 pollen season, accompanied by a full range of community, health and emergency sector awareness raising and education activities. The system uses a categorical risk-based approach, combining operational forecasting of gusty winds in severe thunderstorms with forecasts of high ambient grass pollen concentrations, which together generate the risk of epidemic thunderstorm asthma. This system now provides the first daily epidemic thunderstorm asthma risk warning service in the world that covers a wide area, and integrates into the health, ambulance and emergency management sector.

At the end of each season the partners meet to review the performance of the warning system, including its ability to predict the hazard (i.e. the weather and grass pollen conditions associated with thunderstorm asthma risk) and the impact (unusually high numbers of people presenting to hospital emergency departments with asthma symptoms). The warnings show modest skill in discriminating between days with and without health impacts.

This cyclical review process has led to continuous improvements in all aspects of the warnings system. These include more accurate grass pollen forecasts based on machine learning, progressive installation of automated pollen monitors to replace manual pollen counting, near real time detection of asthma spikes in hospital emergency departments based on natural language processing, and use of value-oriented metrics to tune the weather and grass pollen thresholds to optimize warning performance.

How to cite: Ebert, E., Csutoros, D., Black, J., Lampugnani, E. R., Nattala, U., and Newbigin, E.: Using a value chain to develop a new warning service from scratch - epidemic thunderstorm asthma risk forecasts in Victoria, Australia, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-631, https://doi.org/10.5194/ems2024-631, 2024.

15:00–15:15
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EMS2024-810
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Online presentation
Effectiveness of the flash flood warning value chain: case study analysis of three recent high-impact events in Australia 
Carla Mooney, David Wilke, Karen Hudson, and Victoria Heinrich

Flash flooding presents a significant and increasing risk to public safety across many regions of Australia. This type of flooding, which typically occurs over small spatial scales within 6 hours of the onset of rainfall, is often classed as "high-impact, low probability" and is generally difficult to predict. This is because of the uncertainties in forecasting the intensity and spatial-temporal distribution of rainfall and the resulting landscape response. The short timescales associated with flash flooding also mean that there is limited opportunity to warn communities and trigger protective actions during an event.

The flash flood warning value chain is complex and involves several inter-related components (from forecasts, observations and warnings through to communication, decisions and response). There are multiple organisations involved, with differing roles and responsibilities, and information flows through the value chain via various channels.

In order to identify strategies to improve it is important to understand what is working well in the current service and where there are opportunities for development. This requires significant collaboration with partner agencies to identify pain points with the current approach and needs for a future service.

In Australia, the primary responsibility for flash flood warnings lies with the states and territories through emergency services agencies and local councils. The Bureau of Meteorology's role is to provide forecasts, nowcasts and observations for severe weather conditions and to issue warnings for heavy rainfall that may lead to flash flooding.

This study will evaluate the effectiveness of the warning value chain through case studies of three recent high-impact flash flood events in Australia: Adelaide, South Australia, November 2023; Hunter Valley, New South Wales, July 2022; Hobart, Tasmania, May 2018. The case study approach will follow the guidelines used in the World Meteorological Organisation (WMO) World Weather Research Programme (WWRP) High Impact Weather Warning Value Chain project. This project uses a multidisciplinary approach combining physical and social science with practitioner perspectives to examine the end-to-end function of the warning service.

The outcomes of the analysis will include recommendations to help frame how future services and products can be developed to provide usable and useful intelligence to emergency services agencies and to the broader Australian community during flash flood events.

How to cite: Mooney, C., Wilke, D., Hudson, K., and Heinrich, V.: Effectiveness of the flash flood warning value chain: case study analysis of three recent high-impact events in Australia, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-810, https://doi.org/10.5194/ems2024-810, 2024.

15:15–15:30
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EMS2024-1016
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Onsite presentation
Drought impact-based forecasting: Trade-offs between indicators and impacts 
Anastasiya Shyrokaya, Florian Pappenberger, Gabriele Messori, Ilias Pechlivanidis, Hannah Cloke, and Giuliano Di Baldassarre

Despite the progress in seasonal drought forecasting, it remains challenging to identify suitable drought indices for accurately predicting the impacts of a future drought event. In this study, we identified relationships across Europe between the forecasting skill of various drought indices and the estimated drought impacts. We calculated the indices over various accumulation periods, and assessed the forecasting skill of indices computed based on ECMWF’s seasonal forecast system SEAS5. An evaluation was performed by computing the same indices from the ERA5 reanalysis data and comparing them across various verification metrics, including deterministic Correlation Coefficients, MSE, RMSE, MAE, and probabilistic Brier and Rank Probability performance and skill scores. We further conducted a literature review of the studies assessing the performance of the indices in terms of estimating drought impacts across Europe. We finally performed a trade-off analysis and mapped the drought indices based on their drought forecasting and drought impact estimating skills at the NUTS1 regional level.

Our analysis reveals seasonal trends and spatio-temporal patterns in the forecast performance of drought indices with different accumulation periods computed from SEAS5 with various lead times. Overall, this analysis is a step forward to detect the most suitable drought indices for predicting drought impacts across Europe. Here, not only we present a new approach for evaluating the relationship between drought indices and impacts, we also resolve the dilemma of choosing the indices to be incorporated in the impact functions. Such scientific advancements are setting significant contributions to the emerging field of operational impact-based forecasting and operational drought early warning services.

How to cite: Shyrokaya, A., Pappenberger, F., Messori, G., Pechlivanidis, I., Cloke, H., and Di Baldassarre, G.: Drought impact-based forecasting: Trade-offs between indicators and impacts, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-1016, https://doi.org/10.5194/ems2024-1016, 2024.

Posters: Wed, 4 Sep, 18:00–19:30 | Poster area 'Galaria Paranimf'

Display time: Wed, 4 Sep, 08:00–Thu, 5 Sep, 13:00
Chairperson: David Hoffmann
Early Warning of Drought
GP13
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EMS2024-658
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Online portal »Drought meter« for monitoring the drought situation in Slovenia 
Anže Medved, Andreja Sušnik, Andreja Moderc, Živa Vlahović, and Maja Žun

The frequency of droughts in Slovenia has been increasing in recent decades. In the last twenty years we have recorded 7 droughts that affected Slovenia on the scale of a natural disaster, with the most recent one in 2022 causing around 148 million euros of direct damage to agriculture. Droughts have been occurring with increasing intensity, and in areas and seasons where they have not been a problem in the past.

For the purpose of detecting drought conditions in near real time and informing the public about these, Slovenian Environment Agency has developed the »Drought meter« online portal where estimated drought conditions in three parts of the water cycle (topsoil layer, surface water, groundwater) are published on a weekly basis throughout the year. For each part of the water cycle, drought conditions are monitored at representative stations using a specific indicator; in case of topsoil layer, the surface water balance for the past 30 days is used. Regional estimation of drought conditions is then determined based on a percentile analysis of the indicator at representative stations, which gives information on how often in the past similar conditions have occurred in the selected time period.

In addition to drought conditions in the three parts of the water cycle, »Drought meter« also consists of a climate analysis of three basic variables influencing these conditions, namely temperature, precipitation and reference evapotranspiration over the last 7 and last 30 days. This is also done on a weekly basis, where for each variable we highlight the spatial distribution and meteorological stations that deviated the most. For the last 30 days, maps of deviations by percentile classes are shown. An outlook for the following week is also provided through a meteorological forecast, consisting of a description of the synoptic situation for the coming week and an estimate of expected precipitation amount and temperature range by the end of the selected period.

The »Drought meter« online portal represents a progress in providing information on drought conditions in Slovenia, since near real time drought information for all three parts of the water cycle is available in one place and on a uniform spatial and temporal scale. In our talk, we will provide an overview of the development of the drought in 2022. That year the estimated drought conditions in »Drought meter« also served as the basis for the competent authorities to determine the onset of the period for assessing damage to agricultural crops due to drought.

How to cite: Medved, A., Sušnik, A., Moderc, A., Vlahović, Ž., and Žun, M.: Online portal »Drought meter« for monitoring the drought situation in Slovenia, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-658, https://doi.org/10.5194/ems2024-658, 2024.

GP14
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EMS2024-327
Understanding reference evapotranspiration distribution and evolution in the Northwestern Mediterranean basin 
Maria Cortès and Vicent Altava-Ortiz

Drought episodes are among the most devasting natural disasters impacting agriculture, forests, the environment, and economic activity. Catalonia, in the Northwestern Mediterranean basin, is currently experiencing its most severe drought episode on record.
For a comprehensive examination of drought episodes, it is crucial to consider different processes involved in water balance. However, many studies tend to focus solely on precipitation scarcity, often overlooking other critical variables like evapotranspiration or approximating it through simplified methods.
While uncertainty persists regarding present and future precipitation patterns in the Mediterranean basin, the temperature is showing a steady increase and is projected to rise even more in the future. This rise could intensify evapotranspiration rates, exacerbating drought episodes. 
Nonetheless, it is essential to note that evapotranspiration is not only influenced by temperature; other meteorological variables such as solar radiation, relative humidity, and wind also play significant roles. 
This study aims to analyze the relative impact of different meteorological variables on evapotranspiration to better understand the factors affecting this relevant phenomenon for drought management in Catalonia. Such insights will provide valuable information for adapting to future droughts episodes.
The study proposes an  in-depth analysis of evapotranspiration in Catalonia, using data collected by the XEMA observation network of the Meteorological Service of Catalonia (SMC). This network extensively covers the region, providing data for calculating evapotranspiration on  monthly, daily, and even hourly time scales. Taking advantage of this dataset, the Penman-Monteith formulation is employed to compute reference crop evapotranspiration (ETo). The evolution of this variable in the territory, its spatial distribution, and case studies such as the recent 2020-2024 episode are studied.

How to cite: Cortès, M. and Altava-Ortiz, V.: Understanding reference evapotranspiration distribution and evolution in the Northwestern Mediterranean basin, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-327, https://doi.org/10.5194/ems2024-327, 2024.

GP15
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EMS2024-81
Characterizing Onsets and Terminations of Soil Moisture Droughts in Europe 
Woon Mi Kim, Santos J. González-Rojí, Isla R. Simpson, and Daniel Kennedy

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.

How to cite: Kim, W. M., González-Rojí, S. J., Simpson, I. R., and Kennedy, D.: Characterizing Onsets and Terminations of Soil Moisture Droughts in Europe, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-81, https://doi.org/10.5194/ems2024-81, 2024.