It is evident that anthropogenic climate change is already affecting weather and climate extreme events such as floods and droughts across the globe at an unprecedented rate. Such extreme events can result in hazards and disasters with associated, strong and negative impacts on the environment, socio-economy, and human health. This is particularly relevant in the urban environment, where half of the global population resides. Despite the increased awareness of the risks of extreme events, cities are highly prone to the associated hazards. Climate change is impeding the attribution and quantification of the risk of unprecedented hydrometeorological events.
Particularly in coastal megacities such as Shenzhen and Shanghai, hydrometeorological extremes may result in different types of floods: floods caused and modulated by storm surges such as typhoons in combination with tide (coastal floods), heavy precipitation events (pluvial floods) as well as large-scale riverine floods. Special emphasis is given to risk assessment of compounding events, i.e. co-occuring events of different extremes at nearly the same time and place such as coastal floods in combination with pluvial floods, as can be caused by typhoons.
Within this context, this SI aims to strengthen transdisciplinary physically based research activities worldwide, including hydrology, hydraulics, as well as meteorology and climatology. This SI will not address studies about adaptation measures, economic considerations, and policy recommendations for urban environmental development.

The inter-journal SI is open for all submissions within its scope. Submissions within the following subtopics (not restricted to those) will be considered.

1. Characteristics and process understanding of historical extreme events in the urban environment

• Analysis of changes in occurrence and magnitude in single and compound extremes
• Identification of the relevant underlying physics (drivers such as teleconnections and circulation patterns) associated with extreme events

2. Attribution and impact analysis of extreme events in the urban environment

• Development of theoretical (statistical) frameworks for identifying modulators and drivers of (compounding) extreme events such as multivariate or vine copulas
• Development of process-based compartment-crossing modeling systems from climate to hydraulic models (e.g., storm surge modeling in coastal cities) for assessing extreme-event-induced hazards and disasters
• Attribution and impact studies of future climate change on urban extreme events from all over the world

Drought is a complex phenomenon resulting from interactions between physical and social systems that impacts both societies and ecosystems around the world yearly. Drought risks are systemic and increasing (UNDRR, 2021). In 2019, scientists from African countries urged the world to end the drought in drought research and asked for more support to better identify and prepare for drought disasters (Padma, 2019). Preparing for future drought requires a thorough understanding of the complexities of systemic drought risk and adaptation feedbacks, effective drought risk management, and good communication of the risk and potential adaptation options. In the special issue on Drought, society, and ecosystems, we aim to showcase the diverse interdisciplinary research being done on the interactions between drought, ecosystems, and people (including human-induced climate change and management).

We solicit contributions (commentaries, review articles, original research articles) from different perspectives on this interdisciplinary topic from research scientists of different fields, students, practitioners, and stakeholders. It will be a unique opportunity to further our understanding of drought risk, adaptation, and feedbacks. The co-listing of this special issue under the Copernicus journals Natural Hazards and Earth System Sciences (NHESS), Hydrology and Earth System Sciences (HESS), Geoscience Communication (GC), and Biogeosciences (BG) allows for more diversity in perspectives.

Abstracts that fall under one of the following (or related) themes will be considered:

• drought risk analysis
• drought impact attribution
• water security in diverse contexts
• drought risk management and communication
• co-creation of drought information services
• drought in (socio-)ecological systems
• drought and the food–water–energy–environment nexus
• influence of human activities on drought hazard
• socio-hydrology of human–drought interactions
• drought and vulnerability (in ecological and/or social systems)
• drought adaptation (in ecological and/or social systems)
• climate change impacts on drought/water security.

Manuscripts with diverse authorships and with case studies in different geographic regions are especially welcomed. The special issue arises from the International Association of Hydrological Sciences (IAHS) Panta Rhei working group Drought in the Anthropocene and aims to showcase the research done on drought–society–ecosystem interactions during the IAHS Panta Rhei decade (2013–2023). However, unsolicited contributions are also highly encouraged. The guest editors aim for diversity and balance in contributions and authors, encouraging researchers from countries underrepresented in science, women, and minorities to contribute to this special issue.

References:

UNDRR: GAR Special Report on Drought 2021, United Nations Office for Disaster Risk Reduction, ISBN 9789212320274, 2021.

Padma, T.V.: African nations push UN to improve drought research, Nature, 573, 319-320, https://doi.org/10.1038/d41586-019-02760-9, 2019.

Climate change in high-mountain regions is associated with significant change in vegetation dynamics, snow coverage, glacier mass balance, and permafrost, which have led to profound changes in both hydrological regimes and their extremes, making the “water towers” vulnerable. Hydrological regimes and their responses to climate change and its associated cryospheric change in high-mountain regions are quite complicated due to intertwined interactions among multiple processes (i.e. ice melting, snow melting, permafrost degradation, and rainfall–runoff) as well as flow pathways. Critical knowledge gaps and large observational uncertainties pose additional challenges for predicting hydrological response to the co-evolution of climate, cryosphere, and biosphere in the high-mountain regions globally.

This special issue calls for a wide range of submissions across a series of disciplines with a hydrological, climatological, and cryospherical perspective across global or regional high-mountain regions, with a focus on exploring the co-evolutional mechanisms of the soil–ice–snow–vegetation system in the context of climate change and their impacts on both hydrological regimes and their extremes. Potential submissions can be in but are not limited to the following areas:

• review of the important issues and methodologies in global or regional high-mountain hydrological studies;
• novel approaches to studying hydrological response to climate and land surface property changes over alpine regions;
• spatial, seasonal/temporal, or elevational patterns and co-evolution mechanisms in vegetation, snow, glaciers, and permafrost as well as their response to climate change and impacts on hydrology in high-mountain regions;
• global or regional climate change and its impacts on the biosphere, cryosphere, and hydrosphere in high-mountain regions;
• observations and projections of changes and variability in hydrological regimes and their extremes in global or regional high-mountain regions;
• integrated database of hydrological and climatological variables in global or regional high-mountain regions.

High-latitude regions are experiencing amplified anthropogenic global warming. Cryospheric changes (e.g. permafrost thaw, snow and ice accumulation, and melt) are strongly coupled with the hydrologic cycle and severely impact the amount and seasonality of groundwater recharge and streamflow generation and associated biogeochemical cycling. These widespread changes, in turn, affect ecological and human systems, with impacts evident even in the ocean. This special issue aims to foster knowledge exchange across communities to gain a better understanding of coupled processes between the cryosphere, hydrology, ecosystems, and humans. We welcome all contributions on topics related to cold-region hydrology with a focus on inter- and transdisciplinary approaches and particularly invite contributions targeting the following aspects:

• climate-change-induced cryospheric alterations and impacts on the water cycle in northern environments, e.g. changes in the snowpack, glacier recession, permafrost thaw, stream discharge, lake size, and wildfires;
• interdisciplinary research that furthers our understanding of the nexus between hydrological, biogeochemical, and ecosystem processes in cold-region environments;
• the impacts of current (e.g. mining, logging, dam building) and past (e.g. peatland drainage/restoration) land-use changes in high-latitude regions;
• transdisciplinary research, including knowledge of Indigenous communities and other interested parties, ideally aimed at sustainable co-development of climate change adaptation and mitigation strategies;
• studies providing open tools for the development and testing of transposable models in cold-region environments;
• studies providing information on or presenting new tools for the improvement and standardization of measurement techniques and network design in northern regions.

Macro-scale hydrological and earth system models are used increasingly to study the relationship between climate, water, energy, and land systems. In all these domains, the increased impact of anthropogenic interventions on wide-ranging hydrologic processes have prompted hydrologists to advance the representation of human–water interactions in macro-scale hydrological, land surface, and Earth system models. The simulation of water infrastructures (e.g., reservoirs, diversion dams) is receiving particular attention, owing to their growing presence and impact on both upstream and downstream hydrological, ecological, and socio-environmental processes.

This special issue calls for a broad spectrum of submissions on the representation of water infrastructures in hydrological and Earth system models, with particular emphasis on large-scale studies (from multi-basin to global scale). We welcome submissions focusing on — but not limited to — the following areas.

• Numerical schemes for the representation of spatio-temporal reservoir storage patterns and release decisions across a large fleet of dams
• Integrated models simulating the impact of reservoir systems on water temperature dynamics
• Novel techniques for inferring storage patterns, filling strategies, and operating rules from different data sources (e.g., in situ measurements, satellite data), and their integration in numerical models
• Innovative approaches to the conceptualization and calibration of hydrological and water management models (e.g., combination of process-based and machine learning models)
• Representation of major water transfer schemes (e.g., withdrawal and transfer of water for for urban supply or irrigation)
• Representation and conceptualization of human water use (withdrawal, consumptive use, return flows): source and sector apportionment and prioritization
• Novel applications of hydrological–water management models, such as national-scale river forecasting, multi-sector studies (e.g., water–energy–food nexus), or social, environmental, and ecological impact assessments of water infrastructures
• Comparative studies across basins or modelling approaches

High-latitude regions are experiencing amplified anthropogenic global warming. Cryospheric changes (e.g. permafrost thaw, snow and ice accumulation, and melt) are strongly coupled with the hydrologic cycle and severely impact the amount and seasonality of groundwater recharge and streamflow generation and associated biogeochemical cycling. These widespread changes, in turn, affect ecological and human systems, with impacts evident even in the ocean. This special issue aims to foster knowledge exchange across communities to gain a better understanding of coupled processes between the cryosphere, hydrology, ecosystems, and humans. We welcome all contributions on topics related to cold-region hydrology with a focus on inter- and transdisciplinary approaches and particularly invite contributions targeting the following aspects:

• climate-change-induced cryospheric alterations and impacts on the water cycle in northern environments, e.g. changes in the snowpack, glacier recession, permafrost thaw, stream discharge, lake size, and wildfires;
• interdisciplinary research that furthers our understanding of the nexus between hydrological, biogeochemical, and ecosystem processes in cold-region environments;
• the impacts of current (e.g. mining, logging, dam building) and past (e.g. peatland drainage/restoration) land-use changes in high-latitude regions;
• transdisciplinary research, including knowledge of Indigenous communities and other interested parties, ideally aimed at sustainable co-development of climate change adaptation and mitigation strategies;
• studies providing open tools for the development and testing of transposable models in cold-region environments;
• studies providing information on or presenting new tools for the improvement and standardization of measurement techniques and network design in northern regions.

Drought is a complex phenomenon resulting from interactions between physical and social systems that impacts both societies and ecosystems around the world yearly. Drought risks are systemic and increasing (UNDRR, 2021). In 2019, scientists from African countries urged the world to end the drought in drought research and asked for more support to better identify and prepare for drought disasters (Padma, 2019). Preparing for future drought requires a thorough understanding of the complexities of systemic drought risk and adaptation feedbacks, effective drought risk management, and good communication of the risk and potential adaptation options. In the special issue on Drought, society, and ecosystems, we aim to showcase the diverse interdisciplinary research being done on the interactions between drought, ecosystems, and people (including human-induced climate change and management).

We solicit contributions (commentaries, review articles, original research articles) from different perspectives on this interdisciplinary topic from research scientists of different fields, students, practitioners, and stakeholders. It will be a unique opportunity to further our understanding of drought risk, adaptation, and feedbacks. The co-listing of this special issue under the Copernicus journals Natural Hazards and Earth System Sciences (NHESS), Hydrology and Earth System Sciences (HESS), Geoscience Communication (GC), and Biogeosciences (BG) allows for more diversity in perspectives.

Abstracts that fall under one of the following (or related) themes will be considered:

• drought risk analysis
• drought impact attribution
• water security in diverse contexts
• drought risk management and communication
• co-creation of drought information services
• drought in (socio-)ecological systems
• drought and the food–water–energy–environment nexus
• influence of human activities on drought hazard
• socio-hydrology of human–drought interactions
• drought and vulnerability (in ecological and/or social systems)
• drought adaptation (in ecological and/or social systems)
• climate change impacts on drought/water security.

Manuscripts with diverse authorships and with case studies in different geographic regions are especially welcomed. The special issue arises from the International Association of Hydrological Sciences (IAHS) Panta Rhei working group Drought in the Anthropocene and aims to showcase the research done on drought–society–ecosystem interactions during the IAHS Panta Rhei decade (2013–2023). However, unsolicited contributions are also highly encouraged. The guest editors aim for diversity and balance in contributions and authors, encouraging researchers from countries underrepresented in science, women, and minorities to contribute to this special issue.

References:

UNDRR: GAR Special Report on Drought 2021, United Nations Office for Disaster Risk Reduction, ISBN 9789212320274, 2021.

Padma, T.V.: African nations push UN to improve drought research, Nature, 573, 319-320, https://doi.org/10.1038/d41586-019-02760-9, 2019.

It is evident that anthropogenic climate change is already affecting weather and climate extreme events such as floods and droughts across the globe at an unprecedented rate. Such extreme events can result in hazards and disasters with associated, strong and negative impacts on the environment, socio-economy, and human health. This is particularly relevant in the urban environment, where half of the global population resides. Despite the increased awareness of the risks of extreme events, cities are highly prone to the associated hazards. Climate change is impeding the attribution and quantification of the risk of unprecedented hydrometeorological events.
Particularly in coastal megacities such as Shenzhen and Shanghai, hydrometeorological extremes may result in different types of floods: floods caused and modulated by storm surges such as typhoons in combination with tide (coastal floods), heavy precipitation events (pluvial floods) as well as large-scale riverine floods. Special emphasis is given to risk assessment of compounding events, i.e. co-occuring events of different extremes at nearly the same time and place such as coastal floods in combination with pluvial floods, as can be caused by typhoons.
Within this context, this SI aims to strengthen transdisciplinary physically based research activities worldwide, including hydrology, hydraulics, as well as meteorology and climatology. This SI will not address studies about adaptation measures, economic considerations, and policy recommendations for urban environmental development.

The inter-journal SI is open for all submissions within its scope. Submissions within the following subtopics (not restricted to those) will be considered.

1. Characteristics and process understanding of historical extreme events in the urban environment

• Analysis of changes in occurrence and magnitude in single and compound extremes
• Identification of the relevant underlying physics (drivers such as teleconnections and circulation patterns) associated with extreme events

2. Attribution and impact analysis of extreme events in the urban environment

• Development of theoretical (statistical) frameworks for identifying modulators and drivers of (compounding) extreme events such as multivariate or vine copulas
• Development of process-based compartment-crossing modeling systems from climate to hydraulic models (e.g., storm surge modeling in coastal cities) for assessing extreme-event-induced hazards and disasters
• Attribution and impact studies of future climate change on urban extreme events from all over the world

Macro-scale hydrological and earth system models are used increasingly to study the relationship between climate, water, energy, and land systems. In all these domains, the increased impact of anthropogenic interventions on wide-ranging hydrologic processes have prompted hydrologists to advance the representation of human–water interactions in macro-scale hydrological, land surface, and Earth system models. The simulation of water infrastructures (e.g., reservoirs, diversion dams) is receiving particular attention, owing to their growing presence and impact on both upstream and downstream hydrological, ecological, and socio-environmental processes.

This special issue calls for a broad spectrum of submissions on the representation of water infrastructures in hydrological and Earth system models, with particular emphasis on large-scale studies (from multi-basin to global scale). We welcome submissions focusing on — but not limited to — the following areas.

• Numerical schemes for the representation of spatio-temporal reservoir storage patterns and release decisions across a large fleet of dams
• Integrated models simulating the impact of reservoir systems on water temperature dynamics
• Novel techniques for inferring storage patterns, filling strategies, and operating rules from different data sources (e.g., in situ measurements, satellite data), and their integration in numerical models
• Innovative approaches to the conceptualization and calibration of hydrological and water management models (e.g., combination of process-based and machine learning models)
• Representation of major water transfer schemes (e.g., withdrawal and transfer of water for for urban supply or irrigation)
• Representation and conceptualization of human water use (withdrawal, consumptive use, return flows): source and sector apportionment and prioritization
• Novel applications of hydrological–water management models, such as national-scale river forecasting, multi-sector studies (e.g., water–energy–food nexus), or social, environmental, and ecological impact assessments of water infrastructures
• Comparative studies across basins or modelling approaches

Climate change in high-mountain regions is associated with significant change in vegetation dynamics, snow coverage, glacier mass balance, and permafrost, which have led to profound changes in both hydrological regimes and their extremes, making the “water towers” vulnerable. Hydrological regimes and their responses to climate change and its associated cryospheric change in high-mountain regions are quite complicated due to intertwined interactions among multiple processes (i.e. ice melting, snow melting, permafrost degradation, and rainfall–runoff) as well as flow pathways. Critical knowledge gaps and large observational uncertainties pose additional challenges for predicting hydrological response to the co-evolution of climate, cryosphere, and biosphere in the high-mountain regions globally.

This special issue calls for a wide range of submissions across a series of disciplines with a hydrological, climatological, and cryospherical perspective across global or regional high-mountain regions, with a focus on exploring the co-evolutional mechanisms of the soil–ice–snow–vegetation system in the context of climate change and their impacts on both hydrological regimes and their extremes. Potential submissions can be in but are not limited to the following areas:

• review of the important issues and methodologies in global or regional high-mountain hydrological studies;
• novel approaches to studying hydrological response to climate and land surface property changes over alpine regions;
• spatial, seasonal/temporal, or elevational patterns and co-evolution mechanisms in vegetation, snow, glaciers, and permafrost as well as their response to climate change and impacts on hydrology in high-mountain regions;
• global or regional climate change and its impacts on the biosphere, cryosphere, and hydrosphere in high-mountain regions;
• observations and projections of changes and variability in hydrological regimes and their extremes in global or regional high-mountain regions;
• integrated database of hydrological and climatological variables in global or regional high-mountain regions.