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Item type:Publication, Access status: with files , Groundwater variability is strongly linked to soil temperature across global aquifers(Wiley, 2026-08-05); ; ; ; Groundwater plays a critical role in land-atmosphere interactions by regulating soil moisture and surface energy fluxes, yet its contribution to land-surface processes and heat extremes remains poorly quantified globally. Here, we combine observation-based aquifer records with gridded groundwater table depth (GWD) model outputs (2000–2015) to assess how GWD annual fluctuations covary with soil moisture, evaporation, soil temperature, and heatwave frequency across 1,658 aquifers worldwide. Soil temperature shows the most frequently dominant correlation with GWD among statistically significant, robust relationships (37% of aquifers), followed by evaporation (28%), heatwave frequency (22%), and soil moisture (13%). Aquifers with declining GWD suggest different coupling patterns compared to stable aquifers, with more negative relationships between GWD and evaporation and positive associations between GWD and soil temperature. Our results highlight the importance of incorporating groundwater dynamics into assessments of climate extremes and land-surface processes.Publicationtype: Journal Article15 28 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , A global analysis of the influence of shallow and deep groundwater tables on relationships between environmental parameters and heatwaves(Elsevier, 2026-01-15); ; ; ; Heatwaves increasingly impact ecosystems, human health, and economic activities worldwide. As their frequency and intensity rise, understanding the mechanisms driving heatwave dynamics and interactions with land surface processes becomes crucial. While numerous studies have examined atmospheric and land surface variables, the role of groundwater, through its effects on soil moisture and surface evaporative fluxes, remains less understood. Although modeling approaches at various scales have enhanced our understanding of groundwater-atmosphere coupling, machine learning (ML) enables capturing complex, nonlinear interactions and evaluating the relative importance of key drivers globally. We developed pixel-based ML models to estimate global summer heatwave frequency over the past 21 years. For each pixel, we considered data within a 1.5° radius (149 neighboring pixels), identified as the optimal scale through a saturation radius analysis. We used feature importance metrics to identify the dominant drivers among surface fluxes, land characteristics, atmospheric and hydrological variables, and interpreted these results in relation to contrasting groundwater depths (<10 m and >100 m). We ensured robustness using 10-fold cross-validation and confirmed that results were not driven by randomness with two additional validation runs on a subset of the data, with shuffled targets and randomized covariates. Our findings suggest that geopotential height showed the highest relative importance among predictors in regions with deep groundwater tables, while in areas with shallow groundwater, surface fluxes emerge as the key contributor. Incorporating groundwater-related processes may therefore improve understanding of land-atmosphere interactions and support more robust assessments of future heatwave risks.Publicationtype: Journal Article27 32 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , How shallow and deep groundwater impact environmental parameters correlated with global heatwavesHeatwaves present serious challenges to ecosystems, human health, and a wide range of socioeconomic activities. As the frequency and intensity of heatwaves increase, understanding the mechanisms driving their dynamics and interactions with land surface processes become more important. While extensive research has investigated the influence of various land and atmospheric parameters on heatwaves, less is known about how groundwater depth influences heatwave dynamics through their effects on soil moisture and surface evaporative fluxes (Vogelbacher et al., 2024, Sadeghi et al., 2012). To address this knowledge gap, we investigated how the groundwater depth affects the key parameters controlling heatwave dynamics on a global scale. Specifically, we developed more than 200,000 localized Artificial Intelligence (AI) models to represent the spatial distribution of heatwave frequency over the past 21 years across the world. For each model, a radius of 1.5 degrees (approximately 149 neighboring pixels) is considered in the computation to identify key parameters contributing to heatwaves in that region. We analyzed surface fluxes, as well as atmospheric, hydrological, and local environmental variables, to understand their correlation to heatwaves. Our findings suggest that geopotential height representing atmospheric drivers, is the key predictor of heatwave events in regions with deep groundwater tables (>100 m). In contrast, in areas with shallow groundwater (<10 m), surface fluxes emerge as important contributor to the onset of heatwaves. These findings highlight the less-discussed impact of groundwater depth on atmospheric processes and the important role of soil in linking groundwater and the atmosphere. Our results have important implications for water and land management, emphasizing the need for integrated approaches to understand and address the increasing risks posed by heatwaves.Publicationtype: Conference Paper17 9 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , How does groundwater table influence heatwave occurrences globally?Heatwaves pose a significant threat to ecosystems, human health and a wide range of socio-economic activities. Understanding the mechanisms that drive heatwave dynamics and their interactions with land surface processes is essential as the frequency and intensity of heatwaves are projected to increase in the future. While a number of studies have focused on the role of atmospheric and land surface variables on heatwaves, less is known about how groundwater depth might influence heatwave dynamics through its effects on soil moisture and surface evaporative fluxes. To address this, we examined past heatwave occurrences over a 21-year period, focusing on areas with shallow and deep groundwater levels in different climate and land cover regions. Furthermore, we examined the relationship between heatwave events and key variables across different water table levels on a global scale. For this purpose, we developed more than 200,000 localized artificial intelligence (AI) models to represent summer heatwave frequency across the globe. For each location (pixel), we considered data within a 1.5 degree radius (approximately 149 neighboring pixels) to identify key variables that contribute to heatwave occurrence. We used the model's built-in feature-importance metrics and tailored AI techniques to determine which variables, among surface fluxes and atmospheric, hydrological and local environmental variables, primarily govern heatwave occurrence in areas with different groundwater levels. Our results indicate that geopotential height, representing atmospheric drivers, dominates heatwave estimates in regions with deep groundwater levels (>100 m). In contrast, in areas with shallow groundwater (<10 m), surface fluxes emerge as an important contributor to heatwave occurrence. These findings shed light on the less discussed impact of groundwater depth on key environmental variables associated with heatwave events, and support sustainable climate adaptation and resource management.Publicationtype: Conference Presentation48 43 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , How does groundwater level influence the occurrence and frequency of heatwaves?Climate extremes (e.g., 2023 European heatwave) have severe consequences on built and natural environments, posing a threat to human wellbeing and economic resilience. A changing climate is expected to increase the frequency and intensity of climate hazards but also their impacts might intensify due to increasing exposure and vulnerability. Land atmosphere interactions have been identified as key drivers for heatwaves, relying significantly on groundwater interactions through its effect on soil moisture, evaporation and thus surface heat fluxes (1, 2). Variation of rainfall patterns and the increase in water demands are expected to influence groundwater dynamics, soil moisture-air temperature feedback processes and subsequently the occurrence of preconditioned compound events, where climate-driven preconditions (rainfall-variability and increase of air temperature), worsen the effects of a hazard (heatwave). The current understanding of groundwater as driver for heatwaves are often limited to regional studies or specific land covers, with few endeavors seeking to characterize global- scale trends and responses. We aim to globally investigate the relation between groundwater levels and heatwave events considering different land cover types and environmental variables by conducting a wide-ranging statistical analysis. We combine a variety of datasets, making use of an existing high resolution groundwater model, climate reanalysis data and remote sensing data. This allows us to distinguish potential drivers of heatwave occurrence which contribute to the development of effective action plans to mitigate climate change's adverse effects.Publicationtype: Conference Poster32 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , An analytical framework to investigate groundwater‐atmosphere interactions influenced by soil propertiesThe interaction between climate and groundwater forms a complex, coupled system that affects land‐atmosphere feedback processes and thus local climatic parameters. We propose an analytical framework that integrates local groundwater information and soil hydrophysical characteristics to identify regions with bidirectional (two‐way) coupling where groundwater is influenced by climatic factors (e.g., precipitation) and may affect local climate (e.g., through surface fluxes). The framework capitalizes on the concept of the evaporation characteristic length to quantify the hydraulic connection of groundwater to the soil surface. To evaluate the framework, we calculate the maximum depth of hydraulic connection Dmax between groundwater and the soil surface in Hamburg, Germany. For regions with Dmax exceeding the groundwater depth (d), a bidirectional mode of coupling is defined, while Dmax < d implies a unidirectional coupling mode. Our results indicate that climate driven evaporation changes potentially alter the coupling between groundwater and climate depending on soil texture. Moreover, soil hydraulic properties and shallow groundwater tables could play a crucial role in shifting land‐atmosphere feedback processes by influencing the coupling mode. This research provides insights into the groundwater‐climate interactions under various climatic conditions and soil textures which could contribute to sustainable land‐use management practices, particularly in regions characterized by bidirectional coupling.Publicationtype: Journal Article21 50 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Modes of interaction and varying feedback between groundwater and climate depending on soil characteristicsClimate, climate variability, and climate change could influence groundwater. Shifts in precipitation patterns, recharge, or snowmelt are among the several climate-related variables with important impacts on groundwater. However, the climate-groundwater relationship is not one-way. Groundwater can also impact the climate itself via its influence on different processes and variables such as evaporation, soil moisture, and vegetation. Understanding the interactions and the feedback relationship between groundwater and climate is crucial for sustainable water resource management and resilient adaptation to climate change. Current understanding of how climate influences groundwater and the resulting feedback from groundwater and its impacts on climate is limited. This is of particular importance in the face of projected climatic changes. Here, we aim to develop a simple analytical framework to extend the projection capabilities required to characterize the climate-groundwater interactions depending on the soil characteristics serving as an intermediate domain between the groundwater and climate systems. Our proposed analytical framework can be used to identify potential regions with significant two-way (bidirectional) interactions between climate and groundwater using soil characteristics and soil water retention curves following the theoretical lines discussed in Shokri and Salvucci (2011) and Or and Lehmann (2019). Using this framework, we identify regions of expected hydraulic connections between groundwater and soil surface, depending on the competition between capillary forces and the limiting gravity and viscous forces, and the groundwater depth (GWD) in the city of Hamburg. We argue that in regions with bidirectional interactions, groundwater is potentially more vulnerable to climate change and variability. Moreover, our initial results suggest that regions with finer textured soils are more sensitive to changes in evaporation and air temperature in terms of hydraulic connections between groundwater and the soil surface, which can influence the groundwater-climate interactions. Our analysis provides the basis for further investigation of the feedback impacts of groundwater on several variables, such as soil moisture, ground cooling capacity, and vegetation patterns under different climate change scenarios. ReferencesOr, D., & Lehmann, P. (2019). Surface evaporative capacitance: How soil typeand rainfall characteristics affect global-scale surface evaporation. Water Resources Research, 55, 519-539.https://doi.org/10.1029/2018WR024050.Shokri, N., Salvucci, G. (2011). Evaporation from porous media in the presence of a water table. Vadose Zone J., 10, 1309-1318.Publicationtype: Conference Paper20