The current approach to defining (flash) droughts in climate and hydrology typically relies on standardized indexes like SPI, SMI, and SPEI, combined with specific thresholds to determine the onset and conclusion of these events. However, this methodology often overlooks a crucial aspect – the impacts that communities experience during these events, such as plant mortality, well drying, or heat stress. We propose a novel framework that integrates the community's perception of extreme events, considering both the impact and risk tolerance of these communities. Our approach involves actively engaging with communities and stakeholders to understand their perception of extreme events, their associated impacts, and their levels of resilience and risk acceptance. By leveraging hydrological and crop models alongside historical and projected climate data, we can analyse conditions associated with specific impacts and the severity of these impacts for each community or user group. Additionally, we can develop local definitions of droughts and other related extreme events that align more closely with community perceptions and relevant impacts. This tailored approach aims to enhance communication and resilience within these communities. We tested this new framework in the farming communities of Illinois (USA), Brandenburg (Germany) and Ceará (Brazil), where we identified varying perceptions of drought impacts. Using these insights, we formulated distinct definitions of flash droughts for different regions, considering local climate conditions and community perspectives. This approach resulted in improved event identification and definition, facilitating more effective communication and empowering community actions.

How to cite: Lima Alencar, P. H., Ford, T. W., and Paton, E. N.: Impact perception as driver for extreme event definition, identification and monitoring, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11341, https://doi.org/10.5194/egusphere-egu24-11341, 2024.

Droughts are among the most destructive natural disasters affecting millions worldwide, profoundly impacting society and ecosystems. The demand for effective drought impact monitoring and reporting systems was proven to be crucial for timely mitigation and response. Traditionally, drought impact monitoring systems rely heavily on manual processing analysis and validation of physical and online reports or costly clipping databases, often lacking real-time information. The manual processing of drought impact reports is not only time-consuming but also prone to inconsistencies and delays in the long term. The sheer volume of data generated daily demands significant human resources, often leading to escalated costs and low viability of the final drought impact databases. These challenges underscore the need for more efficient, cost-effective, and reliable methods to process and analyze drought-related data. Recent advancements in large language models (LLM) and artificial intelligence (AI) tools have opened new pathways for enhancing drought impact monitoring systems. The recent EDORA (The European Drought Observatory for Resilience and Adaptation) project enabled us to employ these novel methods, facilitating the task of populating the European Drought Impact Database (EDID). The specific methodology and workflow we tested involved three steps: (1) automated searching for drought impact-related online media posts, (2) automated text translations, and (3) automated text content analysis. Step (1) of the workflow involved employing Google News Archive Search for EU countries in 2000-2022 to scrape relevant online media reports automatically. Searching was based upon predefined search queries translated into all official EU languages. The media report's content was acquired using the trafilatura Python package. A large number of reports found this way were then, in Step (2), translated to the English language using Amazon AWS Translation service. In order to support a correct selection and classification of the drought impact database’s structure, Step (3) was necessary. The translated reports were further analyzed and classified using the GPT 3.5 API, extracting structured data from unstructured text. Thanks to this semi-automated workflow, we analyzed over 60000 online reports and included over 700 additional entries to the EDID. The difference in these numbers shows that the multi-step workflow is necessary to select only those reports that comply with the drought impact definitions of EDID. The contribution will illustrate the difficulties and successes in each step with specific examples. In conclusion, integrating LLM and AI tools into drought impact monitoring systems presents a significant leap forward in our ability to process vast amounts of data quickly and accurately. While some expert decisions are still necessary in our workflow, this innovation reduces the reliance on manual labor and associated costs.  From an operational risk management perspective, it enhances the responsiveness and effectiveness of drought impact reporting. As we continue to refine and expand these technologies, we anticipate a future where real-time, accurate drought impact monitoring is not just a possibility but a reality.

How to cite: Bláhová, M., Blauhut, V., D’Andrea, M., Rossi, L., Stahl, K., and Szillat, K.: Enhanced drought impact monitoring: integrating automated search, translations, and text analysis into online media report scraping, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8923, https://doi.org/10.5194/egusphere-egu24-8923, 2024.

Droughts in mountains are expected to increase in the future with consequences downstream and beyond mountain ranges. While these conditions are internationally recognized, quantitative data on drought effects and impacts are still lacking or not available. This gap hampers a clear understanding and modelling of drought conditions for future adaptation. For these reasons, unconventional data types (such as newspaper articles) have been recently explored to fill this gap with information on drought extension, duration and impacts. In particular, the 2022-2023 drought in the North of Italy was one of the most impactful events in the modern history of the country causing severe damages for a long period on multiple sectors. However, data on its impacts is not available.

For these reasons, this study aims to create an automatic and open near-real time drought impact inventory from newspaper articles for the Italian Alps focusing on the 2022-2023 event. By doing so, the database allows to investigate drought impacts looking at their dynamics in space, time and across multiple sectors. Building on concepts and classifications from the European Drought Impact Inventory, the Italian Alpine Drought Impact Inventory includes an automatic identification of newspaper article, harvesting and classification of information on drought impacts according to the: geographical area (e.g., municipality, river basins and province), the affected sectors (e.g., agriculture, energy, urban and tourism) and temporal duration of events occurred in the Italian Alps. Information is sourced and categorized from newspaper articles from 2022 on a weekly basis through an automated text analysis of Google News query results which are processed using Natural Language Processing methods of tagging and classification. The resulting inventory provides an open-source database of drought information making data available for further research on droughts.

Preliminary analyses of the Italian Alpine Drought Impact Inventory show the largest number of news reported during the July-2023 period covering multiple sectors, mainly agriculture and water supply. A high number of news can also be observed in March 2022, capturing the early signals of snow drought conditions in the Alps that led to extended impacts during summer and autumn. Overall, the open dataset has the potential to advance the understanding of drought impacts in the Italian Alps towards a better informed implementation of prevention strategies and future climate change adaptation.

How to cite: Terzi, S., Piemontese, L., Schneiderbauer, S., and Pittore, M.: The Italian Alpine Drought Impact Inventory through an automatic text analysis of newspaper articles: the case of 2022-2023 drought, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11009, https://doi.org/10.5194/egusphere-egu24-11009, 2024.

The summer of 2022 marked a turning point for Europe as the largest drought in centuries unfolded, with dire consequences for livelihoods and ecosystems all across the continent. High temperatures and prolonged record-low precipitation underscored the event. The ensuing heatwaves in May, June, and July intensified water uptake, exacerbating conditions all across the continent, and causing secondary hazards, such as wildfires and landslides.

This research offers a comprehensive overview of the 2022 European drought, reconnecting the physical drivers of the drought, to its societal and ecological impacts, and the drought risk management measures implemented by water managers across the continent. To do so, this study relies on a survey submitted to water managers all across the continent. The survey gathered 487 responses from 30 European countries, predominantly from public and governmental organizations, making it one of the largest datasets on response to this event to date. The study shows that while Southwestern Europe bore the initial brunt, the whole continent endured protracted effects. Water managers across Europe almost unanimously acknowledged that the risk of drought is increasing and that its management is becoming more crucial year after year.

Based on the collected data we identified a correlation between increased awareness and improved preparedness post 2018-2019 drought. Yet, while awareness of drought risk is growing rapidly, preparedness lags. Additionally, despite the upward trajectory of drought preparedness, challenges persist in managing large-scale events. Differences among countries are significant, underscoring the need for European-wide coordination.

The type of measures taken varied by region and sector. In particular, water managers in Southern Europe, where agriculture is more prevalent, focussed on water supply-side measures, showing an imperative to preserve business-as-usual operations even in the face of water scarcity. On the other hand, water demand management was more common in Central and Western Europe. Long-term and transformative measures and ecosystem-based measures remain underused, underscoring how drought risk management remains largely responsive and event-focused. As droughts transcend borders, pan-European coordination is paramount to ensure effective drought risk management and address disparities in capacity across countries.

How to cite: Biella, R., Shyrokaya, A., and Ionita, M. and the Drought in the Anthropocene (DitA) working group - Panta Rhei/HELPING: The 2022 European Drought Needs to be a Turning Point for Drought Risk Management: An Overview from Drivers to Impact and Management, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20347, https://doi.org/10.5194/egusphere-egu24-20347, 2024.

In the last few years, the world has experienced numerous extreme droughts with adverse impacts on coupled human and natural systems. While agriculture is the most affected sector, the lack of water due to droughts in our highly interconnected world also affects ecosystems, public water supply, power generation, tourism, water-borne transport and buildings, often with non-linear cascading and systemic impacts. Moreover, droughts also interact with other hazards in complex ways, for example leading to compound heat-drought events, wildfires or aggravated impacts when concurring with other non-climatic hazards and shocks, such as the COVID-19 pandemic. At the same time, responses to droughts can also lead to response risks, for example when the establishment of reservoirs in response to droughts leads to overreliance on these reservoirs and in turn increases the vulnerability of communities, sectors and systems to droughts. Combined, these characteristics pose a serious challenge to our ability to grasp the complexities of drought risks and to manage them in a comprehensive way. To avoid ineffective risk management and maladaptation, a paradigm shift in how we look at, assess and manage drought risks is urgently needed – from a siloed, single-risk (e.g. drought risks for agriculture, energy, transport) to a systemic perspective.  

However, despite more frequent and severe events, systemic drought risk assessment is still incipient compared to that of other meteorological and climate hazards. This is mainly due to the outlined complexity of drought, the high level of uncertainties in its analysis, and the lack of community agreement on a common framework to tackle the problem. Addressing this gap, we propose a novel drought risk framework that highlights the systemic nature of drought risks, and show its operationalization using the example of the 2022 drought in Europe. Our research emphasizes that solutions to tackle growing drought risks should not only consider the underlying drivers of drought risks for different sectors, systems or regions, but also be based on an understanding of sector/system interdependencies, feedbacks, dynamics, compounding and concurring hazards, as well as possible tipping points and globally and/or regionally networked risks.

How to cite: Hagenlocher, M., Naumann, G., Meza, I., Blauhut, V., Cotti, D., Döll, P., Ehlert, K., Gaupp, F., Van Loon, A. F., Marengo, J. A., Rossi, L., Sabino Siemons, A.-S., Siebert, S., Tadege Tsehayu, A., Toreti, A., Tsegai, D., Vera, C., Vogt, J., and Wens, M.: Understanding and managing growing drought risks – the need for a systemic perspective, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4690, https://doi.org/10.5194/egusphere-egu24-4690, 2024.

In the past decades, and notably the last few years, droughts have severely impacted various interconnected socio-economic sectors and ecosystems across the EU. These impacts encompass, among others, extensive losses in both rain-fed and irrigated agriculture, challenges and constraints in public water supply, disruptions in inland shipping, diminished production of hydropower and thermoelectric energy, impaired functioning of terrestrial and freshwater ecosystems, and implications for the tourism industry. In order to better prepare for future drought events in Europe, knowledge on the drivers, spatial patterns and dynamics of drought risks is urgently needed. 

The European Drought Risk Atlas responds to that need by mapping hotspots and risk drivers across diverse systems and regions within the EU. Combining conceptual risk models (impact chains) and a data-driven quantitative drought risk assessment based on machine learning, this Atlas represents a significant stride toward impact-driven drought risk analysis in present and projected global warming levels (+1.5°C, +2.0°C, +3.0°C). It provides a detailed and disaggregated perspective on the risks posed by droughts to societies and ecosystems, with a particular focus on agriculture, public water supply, energy, river transportation, freshwater, and terrestrial ecosystems.

The data-driven analysis reveals that current levels of drought risk in the EU are already notable, with average annual losses presenting economic and environmental threats in nearly all regions. As expected, the Mediterranean region, particularly the Iberian Peninsula, faces high drought risk under both current and projected climate conditions, driven by the escalating dry conditions associated with global warming. However, while drought risk of certain sectors in Europe follows a north-south gradient of overall mean drying (south) and wetting (north) under climate change, the analysis underscores that each sector reacts distinctly to current and projected hazard conditions, exhibiting sector-specific sensitivity. Eastern and Western Europe may experience complex dynamics due to the interplay between drying and wetting patterns and precipitation variability, resulting in different risk conditions depending on the considered sector. While the analysis may still be refined as new data (observations and future climate simulations) become available, this Atlas represents a unique tool of unparalleled value that can shape future EU preparedness and adaptation policies.

How to cite: Rossi, L., Wens, M., De Moel, H., Cotti, D., Sabino Siemons, A.-S., Hagenlocher, M., Van Loon, A., Maetens, W., Masante, D., Toreti, A., Naumann, G., Rudari, R., Meroni, M., Avanzi, F., Ghizzoni, T., and Barbosa, P.: Insights from the European Drought Risk Atlas, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9666, https://doi.org/10.5194/egusphere-egu24-9666, 2024.

Drought hazards have intensified in many world regions during the recent century, exposing multiple environmental and socio-economic systems to increased risks. Nevertheless, estimating drought risk is still challenging due to the complex links between drought hazards and their potentially disastrous impacts. The recently published JRC European drought risk atlas, an outcome of the European Drought Observatory for Resilience and Adaptation (EDORA) project, has utilized a data-driven approach, linking drought’s hazard, vulnerability, and exposure with observed sectoral impacts. This project links theoretical causal impact chains and quantitative outcome-oriented drought risk assessment, resulting in a high-resolution assessment of drought-driven sectoral impacts, which can support drought management, and adaptation policies and actions.

At the European level, long time series of observed impacts may be limited in terms of spatial or sectoral coverage, relevance, or granularity. However, specific countries often collect and compile sub-national resolution impact data relevant to drought risk assessment that can inform management and adaptation policies and actions. Implementation at a subnational scale using customized country specific data can be a valuable tool to assess drought risk and impact. However, ensuring valid and reliable results would require following a standard procedure. We explore this potential and delve one step deeper by conducting a national data-driven drought risk assessment in Romania.

We use data from various Romanian government agencies to examine drought-associated impacts on water supply, hydroelectricity energy production, and cultivated crop production. These spatially explicit national data provide larger coverage (cultivated crops), higher spatial resolution (hydroelectricity generation), and country-relevant data (drinking water supply to households) as compared to using Eurostat data for a Europe-wide approach. Data is not restricted only to these sectors; instead, it allows extending the sectoral coverage beyond that of the European drought risk atlas and exploring drought impacts on livestock productivity, water-dependent tourism, and forestry productivity, which are sectors of specific interest to the country. A preliminary assessment suggests a range of sectoral impacts associated with droughts in Romania. The livestock productivity suffers an average annual loss (AAL) of 1 -2%, the forestry sector presents 3% of AAL, and the tourism sector has the highest AAL, at around 6%.

This proposed talk will focus on the potential of applying the Pan-European data-driven drought risk assessment method with nationally derived and diverse datasets, highlighting its flexibility in incorporating additional sectors. Specifically, we will present results for sectors not accounted for before. Finally, we will provide insights into the opportunities and limitations of standardizing the data-driven approach to conduct country-specific, sub-national drought risk assessments.

How to cite: Fridman, D., Sahu, R., Politti, E., Burek, P., Willaarts, B., Wens, M., Limones Rodriguez, N., and Kahil, T.: Data-driven assessment of drought impacts – exploring sectoral impacts at a subnational scale: a case study for Romania., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7553, https://doi.org/10.5194/egusphere-egu24-7553, 2024.

Sweden is known for its abundance of water resources, while future climatic projections indicate a rise in precipitation and temperature rates. However, droughts had severe effects on the environment, society, and agriculture in 2016, 2017 and 2018, highlighting the need for improved drought monitoring and management. The agricultural sector, in particular, suffered significantly during the 2018, 2021, and 2023 droughts, inquiring the need for enhancements in climate adaptation and preparedness. This study aims to assess the agricultural drought in Sweden with a focus on hazard assessment and its associated impacts. Firstly, we unfold the lessons learnt from continental observatories and national services by evaluating the reliability of the derived information and identifying the added value for local decision making. For this, we compare the simulated soil moisture derived from the LISFLOOD and S-HYPE hydrological models, and we evaluate the modelled simulations against earth observation-based soil moisture from the Copernicus Climate Change Service (C3S) Climate Data Store (CDS). Based on the LISFLOOD model, we used anomalies of the soil moisture index and the combined drought index at a 10-day average and at a 5 km spatial resolution. Daily runoff and soil moisture data were also used from the S-HYPE model at about 13 km² spatial resolution. Secondly, the spatiotemporal drought hazard is assessed using drought indicators to identify drought frequency and intensity. Here, drought indicators such as Standardized Precipitation Index (SPI), Soil Moisture Anomaly (SMA), and Combined Drought Index (CDI) are computed using S-HYPE model outputs. Finally, we evaluate the utility of integrating data from drought indices (SPI-1, SPI-3, SMA and CDI) and crop yield of wheat and potato to improve the understanding of the links between impacts and statistical indices. The relationships between drought onset and yield response are evaluated for different aggregation of time periods and lags (i.e., monthly). The study outputs are used to assess alternative ways to improve decision-making regarding adaptation strategies to reduce agricultural vulnerability and the capability of addressing the challenges posed by a changing climate.

How to cite: Canedo Rosso, C., Nyberg, L., and Pechlivanidis, I.: Agricultural Drought in Sweden: Assessment of Hazard and Impacts, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1646, https://doi.org/10.5194/egusphere-egu24-1646, 2024.

In Taiwan, water storage grapples with challenges from steep slopes, fast-flowing streams, limited land size, and a dense population, intensifying constraints on water resources. Climate-sensitive agriculture, especially vulnerable to drought, faces threats to Taiwan’s food supply, particularly in the Jhuoshuei River Alluvial Plain, crucial for rice cultivation. To investigate the drought-rice yield relationship there, this study focused on Changhua County, chosen for its comprehensive meteorological data, encompassing maximum and minimum temperatures, precipitation, wind speed, relative humidity, and solar radiation. Given the geographical features of Changhua County, where farmers heavily rely on groundwater, drought events may induce land subsidence due to excessive groundwater pumping. Utilizing AquaCrop, a crop-water productivity model developed by the Food and Agriculture Organization of the United Nations, we simulated historical rice yields from the first crop between 2016 to 2021, configuring model parameters with soil properties, groundwater, water quality, and meteorological data. Rice growth conditions were determined by the growth degree days method, and irrigation was modeled with the first two transplanting stages having a 3 cm ponding depth, followed by a third stage with weekly draining and drying, a nutrient phase with 5 cm water, and final drainage before harvesting. For drought assessment, we calculated consecutive drought days and standardized precipitation index (SPI) to evaluate rice yields risk. A sensitivity analysis of temperature, precipitation, additional irrigation, and harvesting time was conducted to comprehend potential effects on rice yield under drought conditions. Despite drought events in 2017, 2019, and 2021 (SPI≦-1), records showed no reduction in rice yields. AquaCrop simulations revealed a rice yield range of 4.02 to 8.51 (t/ha) with a root mean square error (RMSE) of 2.40 (t/ ha) and mean absolute percentage error (MAPE) of 22.66%. Farmers may have mitigated drought impacts by pumping groundwater. Assessing irrigation water by pumping, adding 1 to 3 irrigation events brought simulations closest to rice production records, with an RMSE of 0.06 t/ha and MAPE of 0.65%. The Sensitivity analysis results showed a strong correlation (R²=0.97) between precipitation change and yield. While no clear linear relationship existed between temperature change and yield, reductions in temperature could increase production. Additional irrigation, up to four times during drought, resulted in the highest yield improvement (2.06 t/ha). Beyond the fifth irrigation, yield slightly decreased to 2.05 t/ha, with no further improvements. Lastly, changes in the harvest period exhibited a high correlation with yield (R²=0.99). These findings provide a valuable reference for developing agricultural policies to ensure food supply and farmers’ livelihoods. Future research will explore the relationship between drought and rice yield under climate change scenarios to understand potential agricultural risks better.

How to cite: Huang, S.-H. and Cheng, S.-T.: Assessing the Risk of Rice Production under Drought Conditions in the Jhuoshuei River Alluvial Plain, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3717, https://doi.org/10.5194/egusphere-egu24-3717, 2024.

Droughts represent the main climatic hazard in NE Romania, affecting all agricultural activities to different extents, depending on their timing and intensity. This work investigates the drought risk perception of livestock farmers, together with their coping strategies, through a downscaled approach. Extensive fieldwork complemented by interviews and a survey was carried out during the summers of 2022 and 2023, with the main goal of gathering data from the most drought-sensitive and impacted farmer typology: livestock farmers that practice grazing, depending entirely on the amounts of precipitation and their distribution during the grazing period.

The questionnaire was applied to 185 farmers with different farm settings. This included 64 questions (with response types grouped in 5-point Likert scale, dichotomic, multiple choice, or open items), structured as: (i) the risk perception of the farmers regarding climate-related hazards (awareness, perceived trends of climate hazards, impacts on water and feed supply, animal health, pasture quality, preparedness, trust in authorities); (ii) farm settings (type, size, water supply, restrictive factors, production specificity, animal breed, partnership status, perspectives), and (iii) farmer profile (age, education level, experience, implication, place of living, heat vulnerability, satisfaction level). The statistical analysis was performed in R (univariate, bivariate, and multivariate analysis).

The results include a broad range of correlations and insights, from which we selected an initial subset statistically significant. Respondents considered droughts the most impactful climatic hazard, followed by heat waves, both in the last and the next 10 years. Also, about 75% of the farmers reported an increase in drought intensity and frequency in the last 10 years. In terms of preparedness, 58% of the participants reported that they implemented drought preparedness measures, although they estimate their preparedness level as medium (2.82 mean, 1.1 std). Medium to low levels were also reported by farmers when talking about trusting authorities at county (1.85 mean, 0.82 std), national (2.29 mean, 1.15 std) or European (2.34 mean, 1.26 std) scales to reduce the impact of droughts.

As drought risk perception is a prominent factor to be acknowledged and integrated into drought mitigation strategies, these findings can inform decision-making at regional and local scales. This study marks the start of drought risk perception research in Romania, being the first to address this topic in the country of reference and one of the few and most detailed in Europe.

How to cite: Margarint, M. C., Albulescu, A.-C., Niculita, M., Wu, J., and Tarolli, P.: Drought risk perception and adaptive measures of livestock farmers in NE Romania, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8665, https://doi.org/10.5194/egusphere-egu24-8665, 2024.

Ecosystems in Europe are increasingly faced with more frequent and more intense drought events. The impacts of droughts do not only undermine ecosystem health and the provision of ecosystem services, but can lead to the deterioration of the system’s long-term resilience to droughts. In order to effectively assess, reduce, and manage the risks posed by droughts on ecosystems, it is first necessary to gain a thorough understanding of how droughts affect a particular ecosystem, what the underlying risk drivers and root causes are, and how these interact to produce that risk. 

Addressing this need, we have developed conceptual models of drought risks for two highly-relevant European ecosystem types, forest and freshwater ecosystems. The conceptual models were developed and visualized using the impact chain methodology, building on extensive literature review and expert consultations, and validated in a series of expert workshops. Following this process, the risks of decreased primary production, forest die-off, and soil degradation and desertification were identified for forest ecosystems, and the risk of disruption of environmental flow for freshwater ecosystems.

The resulting impact chains provide insights into how different climatic, ecological, and societal risk drivers interact to produce drought risks for ecosystems, with some drivers being specific to a certain risk (e.g. forest composition), and others shared across them (e.g. societal water demand and abstractions). While some of these drivers relate to purely ecological features (e.g. plant physiology or soil conditions), many relate to how ecosystems are managed, and to the influence of other sectors/systems upon them (e.g. hydropower, river transportation or intensive agriculture and their adverse effects on freshwater ecosystems). Moreover, the impact chains also highlight some of the root causes (e.g. increased demand for energy, farmers' lack of awareness about agriculture's impacts on freshwater ecosystems, or incentives to enhance navigability) behind these drivers, indicating potential entry points for risk reduction and adaptation. 

The visualization in impact chains is useful to enhance the understanding and at the same time break down the complexity of the risks for these systems, which can support data-driven risk assessment, as well as the identification of entry points for risk management and adaptation. 

While in this work the risks posed by droughts for forests and freshwater ecosystems were assessed on European level, the impact chain approach presented here can be used at different scales and transferred to different ecosystems at risk from droughts. Moreover, it can be used to identify common risk drivers between ecosystems that could be addressed jointly, contributing to a more systemic drought risk management. 

How to cite: Sabino Siemons, A.-S., Cotti, D., Wens, M., de Moel, H., Rossi, L., Walz, Y., and Hagenlocher, M.: Understanding drought risks for European ecosystems through conceptual risk models, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18709, https://doi.org/10.5194/egusphere-egu24-18709, 2024.

The accessibility of water resource, encompassing both water quantity and quality, is pivotal for public health and aquatic ecosystem. It has been recognized by water related Sustainable Development Goals (SDGs) such as life on land and below water. This study underscores the importance of integrating these goals in the context of water resource accessibility. We develop water scarcity assessment that accounts for water demands of human activities by further introducing water quantity and quality requirements for different aquatic life uses. This is applied in a case study for Nooksack watershed that featured diverse anadromous fish habitats. In this study, local data including hydrological flows modelled using regional records, local water quality data, and water withdrawal reports are applied for enhancing the geographical specificity of our analysis. Using different geographical scales including management areas, drainages, and NHD stream reaches, along with annual and monthly temporal scales, this study presents a comprehensive view of water scarcity. Our findings reveal different levels of water scarcity across tributaries with residential distributions and the downstream region of the Nooksack River, with the most severe level observed in agriculture intensified area (Lower Nooksack) and moderately to highly developed urban coastal region (Lummi Bay Watershed). Impaired water quality contributes to exacerbated scarcity, especially during summer, peaking in August. The detailed water scarcity examination at stream reach level specifically identifies the border streams located in the Fishtrap drainage of Lower Nooksack as critically affected by both quantity and quality induced water scarcity. It highlights the need of effective management of border watersheds. It is noteworthy that water quality induced deficiencies of instream flow required by aquatic life uses distribute at mostly first level tributaries overlapping with those most affected drainages, but do not surge at some specific locations. The This study offers a novel framework for assessing water resources accessibility at watershed scale, advocating the downscaled application of water scarcity assessment results to the NHD reach level, thereby providing more intuitive and granular insights. 

How to cite: Li, Y., Faustman, E., and Norton, C.: Integrative Assessment of Water Scarcity: A Case Study in the Nooksack Watershed Addressing Human and Aquatic Life Needs, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20107, https://doi.org/10.5194/egusphere-egu24-20107, 2024.

One of the biggest strengths of parametric drought insurance products is that they can trigger payouts independently from observed losses (and expensive loss assessments), potentially increasing the speed of payouts and lowering premiums. To support low-income countries in formulating policies and developing instruments aimed at enhancing their financial resilience against drought, the World Bank’s Crisis and Disaster Risk Finance (CDRF) team and DHI are developing a novel drought risk finance dashboard. The overarching objective is to improve the transparency and accountability related to the development of drought risk financing instruments to strengthen national decision-making and risk ownership in low-income countries. The NextGen Drought Index (NGDI) dashboard is being piloted in Ethiopia, Kenya, and Somalia, with the vision to be implemented across Africa, and ultimately, on a global scale. The new tool allows users to access, visualize, and analyze historical and current drought conditions alongside socio-economic data, such as food insecurity. This enables users to close the critical gap between drought hazard, drought impact, and the performance of financial products. The dashboard optimizes the use of satellite-derived climate datasets, such as estimates of precipitation, soil moisture and vegetation greenness. It empowers users to combine and benchmark climate data from diverse Earth Observation (EO) platforms. This dynamic approach enables the assessment of drought risk and its temporal progression. Since the data must be analysed at a consistent geographical scale, all climate and environmental variables are aggregated and preprocessed for further analysis by governmental partners or regional stakeholders. The NGDI dashboard will be added to the CDRF team’s catalogue of tools. All choices regarding the platform’s architecture and technology prioritize sustainability, scalability, and cost-efficient maintenance. The dashboard was developed under the World Bank Disaster Risk Finance and Insurance Program, funded by the Global Shield Financing Facility (GSFF) and the Global Index Insurance Facility (GIIF).

How to cite: Richaud, B., Anthonj, J., Larsen, O., Enenkel, M., and Plevin, J. L.: NextGen Drought Index Dashboard - Designing and piloting a new satellite data platform to strengthen drought risk financing in the Horn of Africa, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22325, https://doi.org/10.5194/egusphere-egu24-22325, 2024.

Anthropogenic global warming is exacerbating the frequency and severity of extreme droughts, reinforcing cascading effects across sectors and increasing the urgency of research on the systematic risks associated with droughts. Current research on cascading droughts is predominantly constrained to examining the temporal delay response of cross-sectoral droughts within single characterized regions or climate zones. The dynamic spatio-temporal migration of cross-system cascading drought chains across multiple climate zones remains unexplored. In this study, we rely on the highly precise event-by-event link between multiple types of droughts and make the first attempt to investigate the dynamic spatio-temporal migration trajectory of cross-system cascading droughts across multiple climate zones in Central Asia, including arid desert (AD), arid steppe (AS), temperate (T), cold (C) and alpine (Alp). The results capture for the first time the apparent spatial aggregation state of cascading drought events in the three climate zone combinations AD+AS, AD+AS+C+Alp, and AD+AS+Alp. The transition zone, from the alpine to the arid desert (AD+AS+C+Alp), represents a climate zone combination with the highest systematic drought risk zone, marked by the highest occurrence of the four-system cascading drought event involving droughts of precipitation, evaporation, runoff, and soil moisture. The typical cascading drought pattern shows that the hotspot gradually moves away from the Alp and C to AD and AS climate zones, implying the effect of the interplay between different climate zones on drought evolution. Our findings recommend that early warnings of systematic drought risk should not be limited to temporal links alone but should include both spatial and temporal aspects.

How to cite: Tian, L., Huang, J., and Disse, M.: Dynamic spatiotemporal migration of cross-sectoral cascading drought events across climate zones , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17075, https://doi.org/10.5194/egusphere-egu24-17075, 2024.

Droughts can affect a variety of sectors, such as water resources, agricultural yield, and energy security. Moreover, their impacts can cascade or propagate to other regions due to the physical or socioeconomic linkages. Though drought impacts on energy (e.g., hydropower generation) have been well explored, their effects, in tandem with other extremes, such as heatwaves (or compound droughts and hot extremes), across different regions have been less explored. In this study, we demonstrated the compounding risk of droughts in Southwest China and hot extremes in East China (with hydropower transmission from Southwest China), which collectively presents challenges to energy security in East China. We then explore the changes in the characteristics of such spatial compounding of droughts and hot extremes across different regions in historical periods. Finally, future risks of such extremes are also explored based on simulations from Coupled Model Intercomparison Project Phase 6 (CMIP6). This study can be useful for understanding compounding risks with impacts transmitted to remote locations through physical or socio-economical pathways.

How to cite: Hao, Z.: Compounding risks from droughts and hot extremes across different regions due to energy linkages , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4546, https://doi.org/10.5194/egusphere-egu24-4546, 2024.

Understanding the physical mechanisms which contribute towards the rapid intensification of flash droughts is crucial for improving their forecasts. These mechanisms are difficult to elucidate using statistical techniques due to the complex interactions between land surface and atmospheric processes. In order to overcome this limitation, we use a slab model to model the coupled energy and water balance of the land and atmosphere. We develop an analytical framework to disentangle the influence of external forcings and system response driven by the state variables using the energy and water balance equations of the model. We apply the model to six locations selected from different climate regions of India to identify the physical mechanisms of flash droughts. We find that most flash droughts in India happen during the monsoon season, with higher frequency in humid regions of Northeast India and southern peninsular India. We find that all flash droughts occur during periods of deficient rainfall and the drying is predominantly driven by net shortwave radiation. However, the flash droughts differ in terms of contribution of winds towards drying, based on which we classify the flash drought mechanisms into three types: (a) Category 1: flash droughts with wind-driven intensification due to land-atmospheric feedback (b) Category 2: flash droughts with minimal contribution of winds towards drying and (c) Category 3: flash droughts with wind-driven intensification due to advected heat. We also show that although the enhanced vapor pressure deficit is a frequently recurring feature of flash droughts, it is not necessarily the most relevant contributor in their development.  

How to cite: Singh, V. and Apurv, T.: An analytical framework to understand flash drought mechanisms, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5881, https://doi.org/10.5194/egusphere-egu24-5881, 2024.

Droughts cause multiple ecological and social damages. Reliable drought monitoring and forecasting can benefit various sectors by allowing adequate lead times for drought mitigation efforts. Drought indices are key tools to quantify drought severity, but they are currently limited to timescales of monthly or longer. However, shorter-timescale (e.g., daily) drought indices enable more accurate identification of drought characteristics (e.g., onset and cessation time), especially for flash droughts. Here, we propose a daily drought index named daily evapotranspiration deficit index (DEDI) that is constructed based on actual and potential evapotranspiration data. Through comparisons with multiple reference indices and observations, DEDI can well characterize the spatiotemporal evolution of regional drought events that occurred in North China, Southwest China, eastern Northwest China, and Northeast China in the spring and summer of 2019. We have publicly shared the DEDI dataset with a high spatial resolution (0.25°) and a long time series (1979–2022) covering global land areas, available at https://doi.org/10.5281/zenodo.7768534. The dataset has also been validated to have the capability to capture dry and wet variations and to detect ecology- or agriculture-related droughts at a global scale. Overall, the DEDI indicator could be regarded as a practical solution to facilitate flash drought monitoring and early warning.

How to cite: Zhang, X., Duan, J., Cherubini, F., and Ma, Z.: A daily evapotranspiration-based drought indicator in characterizing spatiotemporal evolution of flash droughts, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2705, https://doi.org/10.5194/egusphere-egu24-2705, 2024.

Flash droughts are characterized by their abrupt onset and rapid intensification. Identifying and quantifying the factors that trigger and accelerate the onset of flash droughts is crucial for establishing reliable early warning systems, and thus alleviate their detrimental impacts on agriculture, ecosystems, and water resources. Recent findings indicate that the combined influence of soil moisture depletion and atmospheric aridity contributes to the faster onset of flash droughts. However, the understanding of the dynamic and thermodynamic processes that expedite this rapid onset still remains limited. In this study, we utilized a drought index derived by a state-of-the-art generation of land evaporation model (the fourth version of the Global Land Evaporation Amsterdam Model; GLEAM v4.0), to investigate the spatial distribution and trends in flash drought onset speeds from 1980 to 2023. Our goal was to quantify the relative contributions of atmospheric circulation and evaporation to the trends in onset speed. Our results reveal that the transition from evaporation being energy-limited to water-limited serves as a sufficient condition for flash drought onset in humid and semi-humid regions. The onset speed of flash droughts has exhibited a significant increase since 1980, with intensified atmospheric circulation identified as a key driver for the increasing onset rates. Additionally, elevated evaporation, resulting from increased soil moisture and evaporative demand in the preceding period, emerges as the primary thermodynamic and dynamic factor expediting flash drought onset. This study enhances our understanding of the dynamic and thermodynamic drivers underlying flash droughts, contributing to the advancement of the flash drought onset mechanism. Moreover, the insights gained from this research provide valuable information for predicting flash droughts and developing strategies for effective mitigation.

How to cite: Gou, Q., Koppa, A., Miralles, D., and Yuan, H.: Relative contributions of atmospheric circulation and evaporation to the faster onset of flash droughts, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3057, https://doi.org/10.5194/egusphere-egu24-3057, 2024.