Articles | Volume 28, issue 15
https://doi.org/10.5194/hess-28-3665-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/hess-28-3665-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Technical note
| 
13 Aug 2024
Technical note |
| 13 Aug 2024
| 13 Aug 2024
Technical Note: The divide and measure nonconformity – how metrics can mislead when we evaluate on different data partitions
Department of Compound Environmental Risks, Helmholtz Centre for Environmental Research – UFZ, Leipzig, Germany
Martin Gauch
Google Research, Zurich, Switzerland
Frederik Kratzert
Google Research, Vienna, Austria
Grey Nearing
Google Research, Mountain View, California, USA
Jakob Zscheischler
Department of Compound Environmental Risks, Helmholtz Centre for Environmental Research – UFZ, Leipzig, Germany
Department of Hydro Sciences, TUD Dresden University of Technology, Dresden, Germany
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In this paper, we propose a novel data-driven approach for
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Hydrol. Earth Syst. Sci., 27, 1865–1889, https://doi.org/10.5194/hess-27-1865-2023, https://doi.org/10.5194/hess-27-1865-2023, 2023
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Hybrid forecasting systems combine data-driven methods with physics-based weather and climate models to improve the accuracy of predictions for meteorological and hydroclimatic events such as rainfall, temperature, streamflow, floods, droughts, tropical cyclones, or atmospheric rivers. We review recent developments in hybrid forecasting and outline key challenges and opportunities in the field.
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Hydrol. Earth Syst. Sci., 26, 6339–6359, https://doi.org/10.5194/hess-26-6339-2022, https://doi.org/10.5194/hess-26-6339-2022, 2022
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Using a novel explainable machine learning approach, we investigated the contributions of precipitation, temperature, and day length to different peak discharges, thereby uncovering three primary flooding mechanisms widespread in European catchments. The results indicate that flooding mechanisms have changed in numerous catchments over the past 70 years. The study highlights the potential of artificial intelligence in revealing complex changes in extreme events related to climate change.
Natacha Le Grix, Jakob Zscheischler, Keith B. Rodgers, Ryohei Yamaguchi, and Thomas L. Frölicher
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Compound events threaten marine ecosystems. Here, we investigate the potentially harmful combination of marine heatwaves with low phytoplankton productivity. Using satellite-based observations, we show that these compound events are frequent in the low latitudes. We then investigate the drivers of these compound events using Earth system models. The models share similar drivers in the low latitudes but disagree in the high latitudes due to divergent factors limiting phytoplankton production.
Grey S. Nearing, Daniel Klotz, Jonathan M. Frame, Martin Gauch, Oren Gilon, Frederik Kratzert, Alden Keefe Sampson, Guy Shalev, and Sella Nevo
Hydrol. Earth Syst. Sci., 26, 5493–5513, https://doi.org/10.5194/hess-26-5493-2022, https://doi.org/10.5194/hess-26-5493-2022, 2022
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When designing flood forecasting models, it is necessary to use all available data to achieve the most accurate predictions possible. This manuscript explores two basic ways of ingesting near-real-time streamflow data into machine learning streamflow models. The point we want to make is that when working in the context of machine learning (instead of traditional hydrology models that are based on
bio-geophysics), it is not necessary to use complex statistical methods for injecting sparse data.
Sella Nevo, Efrat Morin, Adi Gerzi Rosenthal, Asher Metzger, Chen Barshai, Dana Weitzner, Dafi Voloshin, Frederik Kratzert, Gal Elidan, Gideon Dror, Gregory Begelman, Grey Nearing, Guy Shalev, Hila Noga, Ira Shavitt, Liora Yuklea, Moriah Royz, Niv Giladi, Nofar Peled Levi, Ofir Reich, Oren Gilon, Ronnie Maor, Shahar Timnat, Tal Shechter, Vladimir Anisimov, Yotam Gigi, Yuval Levin, Zach Moshe, Zvika Ben-Haim, Avinatan Hassidim, and Yossi Matias
Hydrol. Earth Syst. Sci., 26, 4013–4032, https://doi.org/10.5194/hess-26-4013-2022, https://doi.org/10.5194/hess-26-4013-2022, 2022
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Early flood warnings are one of the most effective tools to save lives and goods. Machine learning (ML) models can improve flood prediction accuracy but their use in operational frameworks is limited. The paper presents a flood warning system, operational in India and Bangladesh, that uses ML models for forecasting river stage and flood inundation maps and discusses the models' performances. In 2021, more than 100 million flood alerts were sent to people near rivers over an area of 470 000 km2.
Juliane Mai, Hongren Shen, Bryan A. Tolson, Étienne Gaborit, Richard Arsenault, James R. Craig, Vincent Fortin, Lauren M. Fry, Martin Gauch, Daniel Klotz, Frederik Kratzert, Nicole O'Brien, Daniel G. Princz, Sinan Rasiya Koya, Tirthankar Roy, Frank Seglenieks, Narayan K. Shrestha, André G. T. Temgoua, Vincent Vionnet, and Jonathan W. Waddell
Hydrol. Earth Syst. Sci., 26, 3537–3572, https://doi.org/10.5194/hess-26-3537-2022, https://doi.org/10.5194/hess-26-3537-2022, 2022
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Model intercomparison studies are carried out to test various models and compare the quality of their outputs over the same domain. In this study, 13 diverse model setups using the same input data are evaluated over the Great Lakes region. Various model outputs – such as streamflow, evaporation, soil moisture, and amount of snow on the ground – are compared using standardized methods and metrics. The basin-wise model outputs and observations are made available through an interactive website.
Jonathan M. Frame, Frederik Kratzert, Daniel Klotz, Martin Gauch, Guy Shalev, Oren Gilon, Logan M. Qualls, Hoshin V. Gupta, and Grey S. Nearing
Hydrol. Earth Syst. Sci., 26, 3377–3392, https://doi.org/10.5194/hess-26-3377-2022, https://doi.org/10.5194/hess-26-3377-2022, 2022
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The most accurate rainfall–runoff predictions are currently based on deep learning. There is a concern among hydrologists that deep learning models may not be reliable in extrapolation or for predicting extreme events. This study tests that hypothesis. The deep learning models remained relatively accurate in predicting extreme events compared with traditional models, even when extreme events were not included in the training set.
Thomas Lees, Steven Reece, Frederik Kratzert, Daniel Klotz, Martin Gauch, Jens De Bruijn, Reetik Kumar Sahu, Peter Greve, Louise Slater, and Simon J. Dadson
Hydrol. Earth Syst. Sci., 26, 3079–3101, https://doi.org/10.5194/hess-26-3079-2022, https://doi.org/10.5194/hess-26-3079-2022, 2022
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Alexandre Tuel, Bettina Schaefli, Jakob Zscheischler, and Olivia Martius
Hydrol. Earth Syst. Sci., 26, 2649–2669, https://doi.org/10.5194/hess-26-2649-2022, https://doi.org/10.5194/hess-26-2649-2022, 2022
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River discharge is strongly influenced by the temporal structure of precipitation. Here, we show how extreme precipitation events that occur a few days or weeks after a previous event have a larger effect on river discharge than events occurring in isolation. Windows of 2 weeks or less between events have the most impact. Similarly, periods of persistent high discharge tend to be associated with the occurrence of several extreme precipitation events in close succession.
Elisabeth Tschumi, Sebastian Lienert, Karin van der Wiel, Fortunat Joos, and Jakob Zscheischler
Biogeosciences, 19, 1979–1993, https://doi.org/10.5194/bg-19-1979-2022, https://doi.org/10.5194/bg-19-1979-2022, 2022
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Droughts and heatwaves are expected to occur more often in the future, but their effects on land vegetation and the carbon cycle are poorly understood. We use six climate scenarios with differing extreme occurrences and a vegetation model to analyse these effects. Tree coverage and associated plant productivity increase under a climate with no extremes. Frequent co-occurring droughts and heatwaves decrease plant productivity more than the combined effects of single droughts or heatwaves.
Daniel Klotz, Frederik Kratzert, Martin Gauch, Alden Keefe Sampson, Johannes Brandstetter, Günter Klambauer, Sepp Hochreiter, and Grey Nearing
Hydrol. Earth Syst. Sci., 26, 1673–1693, https://doi.org/10.5194/hess-26-1673-2022, https://doi.org/10.5194/hess-26-1673-2022, 2022
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This contribution evaluates distributional runoff predictions from deep-learning-based approaches. We propose a benchmarking setup and establish four strong baselines. The results show that accurate, precise, and reliable uncertainty estimation can be achieved with deep learning.
Roberto Villalobos-Herrera, Emanuele Bevacqua, Andreia F. S. Ribeiro, Graeme Auld, Laura Crocetti, Bilyana Mircheva, Minh Ha, Jakob Zscheischler, and Carlo De Michele
Nat. Hazards Earth Syst. Sci., 21, 1867–1885, https://doi.org/10.5194/nhess-21-1867-2021, https://doi.org/10.5194/nhess-21-1867-2021, 2021
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Climate hazards may be caused by events which have multiple drivers. Here we present a method to break down climate model biases in hazard indicators down to the bias caused by each driving variable. Using simplified fire and heat stress indicators driven by temperature and relative humidity as examples, we show how multivariate indicators may have complex biases and that the relationship between driving variables is a source of bias that must be considered in climate model bias corrections.
Frederik Kratzert, Daniel Klotz, Sepp Hochreiter, and Grey S. Nearing
Hydrol. Earth Syst. Sci., 25, 2685–2703, https://doi.org/10.5194/hess-25-2685-2021, https://doi.org/10.5194/hess-25-2685-2021, 2021
Short summary
Short summary
We investigate how deep learning models use different meteorological data sets in the task of (regional) rainfall–runoff modeling. We show that performance can be significantly improved when using different data products as input and further show how the model learns to combine those meteorological input differently across time and space. The results are carefully benchmarked against classical approaches, showing the supremacy of the presented approach.
Martin Gauch, Frederik Kratzert, Daniel Klotz, Grey Nearing, Jimmy Lin, and Sepp Hochreiter
Hydrol. Earth Syst. Sci., 25, 2045–2062, https://doi.org/10.5194/hess-25-2045-2021, https://doi.org/10.5194/hess-25-2045-2021, 2021
Short summary
Short summary
We present multi-timescale Short-Term Memory (MTS-LSTM), a machine learning approach that predicts discharge at multiple timescales within one model. MTS-LSTM is significantly more accurate than the US National Water Model and computationally more efficient than an individual LSTM model per timescale. Further, MTS-LSTM can process different input variables at different timescales, which is important as the lead time of meteorological forecasts often depends on their temporal resolution.
Jun Li, Zhaoli Wang, Xushu Wu, Jakob Zscheischler, Shenglian Guo, and Xiaohong Chen
Hydrol. Earth Syst. Sci., 25, 1587–1601, https://doi.org/10.5194/hess-25-1587-2021, https://doi.org/10.5194/hess-25-1587-2021, 2021
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We introduce a daily-scale index, termed the standardized compound drought and heat index (SCDHI), to measure the key features of compound dry-hot conditions. SCDHI can not only monitor the long-term compound dry-hot events, but can also capture such events at sub-monthly scale and reflect the related vegetation activity impacts. The index can provide a new tool to quantify sub-monthly characteristics of compound dry-hot events, which are vital for releasing early and timely warning.
Natacha Le Grix, Jakob Zscheischler, Charlotte Laufkötter, Cecile S. Rousseaux, and Thomas L. Frölicher
Biogeosciences, 18, 2119–2137, https://doi.org/10.5194/bg-18-2119-2021, https://doi.org/10.5194/bg-18-2119-2021, 2021
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Marine ecosystems could suffer severe damage from the co-occurrence of a marine heat wave with extremely low chlorophyll concentration. Here, we provide a first assessment of compound marine heat wave and
low-chlorophyll events in the global ocean from 1998 to 2018. We reveal hotspots of these compound events in the equatorial Pacific and in the Arabian Sea and show that they mostly occur in summer at high latitudes and their frequency is modulated by large-scale modes of climate variability.
Johannes Vogel, Pauline Rivoire, Cristina Deidda, Leila Rahimi, Christoph A. Sauter, Elisabeth Tschumi, Karin van der Wiel, Tianyi Zhang, and Jakob Zscheischler
Earth Syst. Dynam., 12, 151–172, https://doi.org/10.5194/esd-12-151-2021, https://doi.org/10.5194/esd-12-151-2021, 2021
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We present a statistical approach for automatically identifying multiple drivers of extreme impacts based on LASSO regression. We apply the approach to simulated crop failure in the Northern Hemisphere and identify which meteorological variables including climate extreme indices and which seasons are relevant to predict crop failure. The presented approach can help unravel compounding drivers in high-impact events and could be applied to other impacts such as wildfires or flooding.
Jakob Zscheischler, Philippe Naveau, Olivia Martius, Sebastian Engelke, and Christoph C. Raible
Earth Syst. Dynam., 12, 1–16, https://doi.org/10.5194/esd-12-1-2021, https://doi.org/10.5194/esd-12-1-2021, 2021
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Compound extremes such as heavy precipitation and extreme winds can lead to large damage. To date it is unclear how well climate models represent such compound extremes. Here we present a new measure to assess differences in the dependence structure of bivariate extremes. This measure is applied to assess differences in the dependence of compound precipitation and wind extremes between three model simulations and one reanalysis dataset in a domain in central Europe.
Andreia Filipa Silva Ribeiro, Ana Russo, Célia Marina Gouveia, Patrícia Páscoa, and Jakob Zscheischler
Biogeosciences, 17, 4815–4830, https://doi.org/10.5194/bg-17-4815-2020, https://doi.org/10.5194/bg-17-4815-2020, 2020
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This study investigates the impacts of compound dry and hot extremes on crop yields, namely wheat and barley, over two regions in Spain dominated by rainfed agriculture. We provide estimates of the conditional probability of crop loss under compound dry and hot conditions, which could be an important tool for responsible authorities to mitigate the impacts magnified by the interactions between the different hazards.
Frederik Kratzert, Daniel Klotz, Guy Shalev, Günter Klambauer, Sepp Hochreiter, and Grey Nearing
Hydrol. Earth Syst. Sci., 23, 5089–5110, https://doi.org/10.5194/hess-23-5089-2019, https://doi.org/10.5194/hess-23-5089-2019, 2019
Short summary
Short summary
A new approach for regional rainfall–runoff modeling using long short-term memory (LSTM)-based models is presented and benchmarked against a range of well-known hydrological models. The approach significantly outperforms regionally calibrated hydrological models but also basin-wise calibrated models. Furthermore, we propose an adaption of the LSTM that allows us to extract the learned catchment understanding of the model and show that it matches our hydrology expert knowledge.
Inne Vanderkelen, Jakob Zschleischler, Lukas Gudmundsson, Klaus Keuler, Francois Rineau, Natalie Beenaerts, Jaco Vangronsveld, and Wim Thiery
Biogeosciences Discuss., https://doi.org/10.5194/bg-2019-267, https://doi.org/10.5194/bg-2019-267, 2019
Manuscript not accepted for further review
Jakob Zscheischler, Erich M. Fischer, and Stefan Lange
Earth Syst. Dynam., 10, 31–43, https://doi.org/10.5194/esd-10-31-2019, https://doi.org/10.5194/esd-10-31-2019, 2019
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Many climate models have biases in different variables throughout the world. Adjusting these biases is necessary for estimating climate impacts. Here we demonstrate that widely used univariate bias adjustment methods do not work well for multivariate impacts. We illustrate this problem using fire risk and heat stress as impact indicators. Using an approach that adjusts not only biases in the individual climate variables but also biases in the correlation between them can resolve these problems.
Frederik Kratzert, Daniel Klotz, Claire Brenner, Karsten Schulz, and Mathew Herrnegger
Hydrol. Earth Syst. Sci., 22, 6005–6022, https://doi.org/10.5194/hess-22-6005-2018, https://doi.org/10.5194/hess-22-6005-2018, 2018
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In this paper, we propose a novel data-driven approach for
rainfall–runoff modelling, using the long short-term memory (LSTM) network, a special type of recurrent neural network. We show in three different experiments that this network is able to learn to predict the discharge purely from meteorological input parameters (such as precipitation or temperature) as accurately as (or better than) the well-established Sacramento Soil Moisture Accounting model, coupled with the Snow-17 snow model.
Martha M. Vogel, Jakob Zscheischler, and Sonia I. Seneviratne
Earth Syst. Dynam., 9, 1107–1125, https://doi.org/10.5194/esd-9-1107-2018, https://doi.org/10.5194/esd-9-1107-2018, 2018
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Climate change projections of temperature extremes are particularly uncertain in central Europe. We demonstrate that varying soil moisture–atmosphere feedbacks in current climate models leads to an enhancement of model differences; thus, they can explain the large uncertainties in extreme temperature projections. Using an observation-based constraint, we show that the strong drying and large increase in temperatures exhibited by models on the hottest day in central Europe are highly unlikely.
Donghai Wu, Philippe Ciais, Nicolas Viovy, Alan K. Knapp, Kevin Wilcox, Michael Bahn, Melinda D. Smith, Sara Vicca, Simone Fatichi, Jakob Zscheischler, Yue He, Xiangyi Li, Akihiko Ito, Almut Arneth, Anna Harper, Anna Ukkola, Athanasios Paschalis, Benjamin Poulter, Changhui Peng, Daniel Ricciuto, David Reinthaler, Guangsheng Chen, Hanqin Tian, Hélène Genet, Jiafu Mao, Johannes Ingrisch, Julia E. S. M. Nabel, Julia Pongratz, Lena R. Boysen, Markus Kautz, Michael Schmitt, Patrick Meir, Qiuan Zhu, Roland Hasibeder, Sebastian Sippel, Shree R. S. Dangal, Stephen Sitch, Xiaoying Shi, Yingping Wang, Yiqi Luo, Yongwen Liu, and Shilong Piao
Biogeosciences, 15, 3421–3437, https://doi.org/10.5194/bg-15-3421-2018, https://doi.org/10.5194/bg-15-3421-2018, 2018
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Our results indicate that most ecosystem models do not capture the observed asymmetric responses under normal precipitation conditions, suggesting an overestimate of the drought effects and/or underestimate of the watering impacts on primary productivity, which may be the result of inadequate representation of key eco-hydrological processes. Collaboration between modelers and site investigators needs to be strengthened to improve the specific processes in ecosystem models in following studies.
Karsten Schulz, Reinhard Burgholzer, Daniel Klotz, Johannes Wesemann, and Mathew Herrnegger
Hydrol. Earth Syst. Sci., 22, 2607–2613, https://doi.org/10.5194/hess-22-2607-2018, https://doi.org/10.5194/hess-22-2607-2018, 2018
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The unit hydrograph has been one of the most widely employed modelling techniques to predict rainfall-runoff behaviour of hydrological catchments. We developed a lecture theatre experiment including some student involvement to illustrate the principles behind this modelling technique. The experiment only uses very simple and cheap material including a set of plastic balls (representing rainfall), magnetic stripes (tacking the balls to the white board) and sieves (for ball/water gauging).
Jannis von Buttlar, Jakob Zscheischler, Anja Rammig, Sebastian Sippel, Markus Reichstein, Alexander Knohl, Martin Jung, Olaf Menzer, M. Altaf Arain, Nina Buchmann, Alessandro Cescatti, Damiano Gianelle, Gerard Kiely, Beverly E. Law, Vincenzo Magliulo, Hank Margolis, Harry McCaughey, Lutz Merbold, Mirco Migliavacca, Leonardo Montagnani, Walter Oechel, Marian Pavelka, Matthias Peichl, Serge Rambal, Antonio Raschi, Russell L. Scott, Francesco P. Vaccari, Eva van Gorsel, Andrej Varlagin, Georg Wohlfahrt, and Miguel D. Mahecha
Biogeosciences, 15, 1293–1318, https://doi.org/10.5194/bg-15-1293-2018, https://doi.org/10.5194/bg-15-1293-2018, 2018
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Our work systematically quantifies extreme heat and drought event impacts on gross primary productivity (GPP) and ecosystem respiration globally across a wide range of ecosystems. We show that heat extremes typically increased mainly respiration whereas drought decreased both fluxes. Combined heat and drought extremes had opposing effects offsetting each other for respiration, but there were also strong reductions in GPP and hence the strongest reductions in the ecosystems carbon sink capacity.
Miguel D. Mahecha, Fabian Gans, Sebastian Sippel, Jonathan F. Donges, Thomas Kaminski, Stefan Metzger, Mirco Migliavacca, Dario Papale, Anja Rammig, and Jakob Zscheischler
Biogeosciences, 14, 4255–4277, https://doi.org/10.5194/bg-14-4255-2017, https://doi.org/10.5194/bg-14-4255-2017, 2017
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We investigate the likelihood of ecological in situ networks to detect and monitor the impact of extreme events in the terrestrial biosphere.
Jakob Zscheischler, Miguel D. Mahecha, Valerio Avitabile, Leonardo Calle, Nuno Carvalhais, Philippe Ciais, Fabian Gans, Nicolas Gruber, Jens Hartmann, Martin Herold, Kazuhito Ichii, Martin Jung, Peter Landschützer, Goulven G. Laruelle, Ronny Lauerwald, Dario Papale, Philippe Peylin, Benjamin Poulter, Deepak Ray, Pierre Regnier, Christian Rödenbeck, Rosa M. Roman-Cuesta, Christopher Schwalm, Gianluca Tramontana, Alexandra Tyukavina, Riccardo Valentini, Guido van der Werf, Tristram O. West, Julie E. Wolf, and Markus Reichstein
Biogeosciences, 14, 3685–3703, https://doi.org/10.5194/bg-14-3685-2017, https://doi.org/10.5194/bg-14-3685-2017, 2017
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Here we synthesize a wide range of global spatiotemporal observational data on carbon exchanges between the Earth surface and the atmosphere. A key challenge was to consistently combining observational products of terrestrial and aquatic surfaces. Our primary goal is to identify today’s key uncertainties and observational shortcomings that would need to be addressed in future measurement campaigns or expansions of in situ observatories.
Jakob Zscheischler, Rene Orth, and Sonia I. Seneviratne
Biogeosciences, 14, 3309–3320, https://doi.org/10.5194/bg-14-3309-2017, https://doi.org/10.5194/bg-14-3309-2017, 2017
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We use newly established methods to compute bivariate return periods of temperature and precipitation and relate those to crop yield variability in Europe. Most often, crop yields are lower when it is hot and dry and higher when it is cold and wet. The variability in crop yields along a specific climate gradient can be captured well by return periods aligned with these gradients. This study provides new possibilities for investigating the relationship between crop yield variability and climate.
Sebastian Sippel, Jakob Zscheischler, Miguel D. Mahecha, Rene Orth, Markus Reichstein, Martha Vogel, and Sonia I. Seneviratne
Earth Syst. Dynam., 8, 387–403, https://doi.org/10.5194/esd-8-387-2017, https://doi.org/10.5194/esd-8-387-2017, 2017
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The present study (1) evaluates land–atmosphere coupling in the CMIP5 multi-model ensemble against an ensemble of benchmarking datasets and (2) refines the model ensemble using a land–atmosphere coupling diagnostic as constraint. Our study demonstrates that a considerable fraction of coupled climate models overemphasize warm-season
moisture-limitedclimate regimes in midlatitude regions. This leads to biases in daily-scale temperature extremes, which are alleviated in a constrained ensemble.
Sebastian Sippel, Jakob Zscheischler, Martin Heimann, Holger Lange, Miguel D. Mahecha, Geert Jan van Oldenborgh, Friederike E. L. Otto, and Markus Reichstein
Hydrol. Earth Syst. Sci., 21, 441–458, https://doi.org/10.5194/hess-21-441-2017, https://doi.org/10.5194/hess-21-441-2017, 2017
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The paper re-investigates the question whether observed precipitation extremes and annual totals have been increasing in the world's dry regions over the last 60 years. Despite recently postulated increasing trends, we demonstrate that large uncertainties prevail due to (1) the choice of dryness definition and (2) statistical data processing. In fact, we find only minor (and only some significant) increases if (1) dryness is based on aridity and (2) statistical artefacts are accounted for.
Bjorn-Gustaf J. Brooks, Ankur R. Desai, Britton B. Stephens, Anna M. Michalak, and Jakob Zscheischler
Biogeosciences Discuss., https://doi.org/10.5194/bg-2016-223, https://doi.org/10.5194/bg-2016-223, 2016
Manuscript not accepted for further review
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CO2 is the primary greenhouse gas, and its abundance in the atmosphere tends to increase during disturbances like drought. This paper demonstrates how CO2 measurements are combined with models to determine not only how strongly different locations influence CO2 measurement stations, but also the capacity of those measurement stations to detect drought effects. Understanding detection sensitivity will help assess what kinds of changes and turnings points can be monitored using atmospheric CO2.
J. Zscheischler, M. Reichstein, S. Harmeling, A. Rammig, E. Tomelleri, and M. D. Mahecha
Biogeosciences, 11, 2909–2924, https://doi.org/10.5194/bg-11-2909-2014, https://doi.org/10.5194/bg-11-2909-2014, 2014
J. v. Buttlar, J. Zscheischler, and M. D. Mahecha
Nonlin. Processes Geophys., 21, 203–215, https://doi.org/10.5194/npg-21-203-2014, https://doi.org/10.5194/npg-21-203-2014, 2014
Related subject area
Subject: Catchment hydrology | Techniques and Approaches: Theory development
Bimodal hydrographs in a semi-humid forested watershed: characteristics and occurrence conditions
Flood drivers and trends: a case study of the Geul River catchment (the Netherlands) over the past half century
Power law between the apparent drainage density and the pruning area
Characterizing nonlinear, nonstationary, and heterogeneous hydrologic behavior using Ensemble Rainfall-Runoff Analysis (ERRA): proof of concept
Stream water sourcing from high-elevation snowpack inferred from stable isotopes of water: a novel application of d-excess values
Elasticity curves describe streamflow sensitivity to precipitation across the entire flow distribution
Ratio Limits of Water Storage and Outflow in Rainfall-runoff Process
Seasonal and interannual dissolved organic carbon transport process dynamics in a subarctic headwater catchment revealed by high-resolution measurements
Links between seasonal suprapermafrost groundwater, the hydrothermal change of the active layer, and river runoff in alpine permafrost watersheds
Technical note: Isotopic fractionation of evaporating waters: effect of sub-daily atmospheric variations and eventual depletion of heavy isotopes
Increased nonstationarity of stormflow threshold behaviors in a forested watershed due to abrupt earthquake disturbance
HESS Opinions: Are soils overrated in hydrology?
Hydrologic implications of projected changes in rain-on-snow melt for Great Lakes Basin watersheds
A hydrological framework for persistent pools along non-perennial rivers
Evidence-based requirements for perceptualising intercatchment groundwater flow in hydrological models
Droughts can reduce the nitrogen retention capacity of catchments
Explaining changes in rainfall–runoff relationships during and after Australia's Millennium Drought: a community perspective
Three hypotheses on changing river flood hazards
A multivariate-driven approach for disentangling the reduction in near-natural Iberian water resources post-1980
Hydrology and riparian forests drive carbon and nitrogen supply and DOC : NO3− stoichiometry along a headwater Mediterranean stream
Event controls on intermittent streamflow in a temperate climate
Inclusion of flood diversion canal operation in the H08 hydrological model with a case study from the Chao Phraya River basin: model development and validation
Flood generation: process patterns from the raindrop to the ocean
Use of streamflow indices to identify the catchment drivers of hydrographs
Theoretical and empirical evidence against the Budyko catchment trajectory conjecture
Spatial distribution of groundwater recharge, based on regionalised soil moisture models in Wadi Natuf karst aquifers, Palestine
Barriers to mainstream adoption of catchment-wide natural flood management: a transdisciplinary problem-framing study of delivery practice
Low hydrological connectivity after summer drought inhibits DOC export in a forested headwater catchment
Rainbow color map distorts and misleads research in hydrology – guidance for better visualizations and science communication
Attribution of growing season evapotranspiration variability considering snowmelt and vegetation changes in the arid alpine basins
Event and seasonal hydrologic connectivity patterns in an agricultural headwater catchment
Exploring the role of hydrological pathways in modulating multi-annual climate teleconnection periodicities from UK rainfall to streamflow
Technical note: “Bit by bit”: a practical and general approach for evaluating model computational complexity vs. model performance
Hillslope and groundwater contributions to streamflow in a Rocky Mountain watershed underlain by glacial till and fractured sedimentary bedrock
A framework for seasonal variations of hydrological model parameters: impact on model results and response to dynamic catchment characteristics
Hydrology and beyond: the scientific work of August Colding revisited
The influence of a prolonged meteorological drought on catchment water storage capacity: a hydrological-model perspective
Hydrological and runoff formation processes based on isotope tracing during ablation period in the source regions of Yangtze River
Importance of snowmelt contribution to seasonal runoff and summer low flows in Czechia
Concentration–discharge relationships vary among hydrological events, reflecting differences in event characteristics
Recession analysis revisited: impacts of climate on parameter estimation
Understanding the effects of climate warming on streamflow and active groundwater storage in an alpine catchment: the upper Lhasa River
Technical note: An improved discharge sensitivity metric for young water fractions
Hydrological signatures describing the translation of climate seasonality into streamflow seasonality
Spatial and temporal variation in river corridor exchange across a 5th-order mountain stream network
Historic hydrological droughts 1891–2015: systematic characterisation for a diverse set of catchments across the UK
A topographic index explaining hydrological similarity by accounting for the joint controls of runoff formation
Trajectories of nitrate input and output in three nested catchments along a land use gradient
Contrasting rainfall-runoff characteristics of floods in desert and Mediterranean basins
Anthropogenic and catchment characteristic signatures in the water quality of Swiss rivers: a quantitative assessment
Zhen Cui, Fuqiang Tian, Zilong Zhao, Zitong Xu, Yongjie Duan, Jie Wen, and Mohd Yawar Ali Khan
Hydrol. Earth Syst. Sci., 28, 3613–3632, https://doi.org/10.5194/hess-28-3613-2024, https://doi.org/10.5194/hess-28-3613-2024, 2024
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We investigated the response characteristics and occurrence conditions of bimodal hydrographs using 10 years of hydrometric and isotope data in a semi-humid forested watershed in north China. Our findings indicate that bimodal hydrographs occur when the combined total of the event rainfall and antecedent soil moisture index exceeds 200 mm. Additionally, we determined that delayed stormflow is primarily contributed to by shallow groundwater.
Athanasios Tsiokanos, Martine Rutten, Ruud J. van der Ent, and Remko Uijlenhoet
Hydrol. Earth Syst. Sci., 28, 3327–3345, https://doi.org/10.5194/hess-28-3327-2024, https://doi.org/10.5194/hess-28-3327-2024, 2024
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We focus on past high-flow events to find flood drivers in the Geul. We also explore flood drivers’ trends across various timescales and develop a new method to detect the main direction of a trend. Our results show that extreme 24 h precipitation alone is typically insufficient to cause floods. The combination of extreme rainfall and wet initial conditions determines the chance of flooding. Precipitation that leads to floods increases in winter, whereas no consistent trends are found in summer.
Soohyun Yang, Kwanghun Choi, and Kyungrock Paik
Hydrol. Earth Syst. Sci., 28, 3119–3132, https://doi.org/10.5194/hess-28-3119-2024, https://doi.org/10.5194/hess-28-3119-2024, 2024
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In extracting a river network from a digital elevation model, an arbitrary pruning area should be specified. As this value grows, the apparent drainage density is reduced following a power function. This reflects the fractal topographic nature. We prove this relationship related to the known power law in the exceedance probability distribution of drainage area. The power-law exponent is expressed with fractal dimensions. Our findings are supported by analysis of 14 real river networks.
James W. Kirchner
Hydrol. Earth Syst. Sci. Discuss., https://doi.org/10.5194/hess-2024-103, https://doi.org/10.5194/hess-2024-103, 2024
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Here I present a new way of quantifying how streamflow responds to rainfall across a range of timescales. This approach can estimate how different rainfall intensities affect streamflow, and how that may vary, depending on how wet the landscape already is when the rain falls. This may help us to understand processes that regulate streamflow, as well as the susceptibility of different landscapes to flooding.
Matthias Sprenger, Rosemary W. H. Carroll, David Marchetti, Carleton Bern, Harsh Beria, Wendy Brown, Alexander Newman, Curtis Beutler, and Kenneth H. Williams
Hydrol. Earth Syst. Sci., 28, 1711–1723, https://doi.org/10.5194/hess-28-1711-2024, https://doi.org/10.5194/hess-28-1711-2024, 2024
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Stable isotopes of water (described as d-excess) in mountain snowpack can be used to infer proportions of high-elevation snowmelt in stream water. In a Colorado River headwater catchment, nearly half of the water during peak streamflow is derived from melted snow at elevations greater than 3200 m. High-elevation snowpack contributions were higher for years with lower snowpack and warmer spring temperatures. Thus, we suggest that d-excess could serve to assess high-elevation snowpack changes.
Bailey J. Anderson, Manuela I. Brunner, Louise J. Slater, and Simon J. Dadson
Hydrol. Earth Syst. Sci., 28, 1567–1583, https://doi.org/10.5194/hess-28-1567-2024, https://doi.org/10.5194/hess-28-1567-2024, 2024
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Elasticityrefers to how much the amount of water in a river changes with precipitation. We usually calculate this using average streamflow values; however, the amount of water within rivers is also dependent on stored water sources. Here, we look at how elasticity varies across the streamflow distribution and show that not only do low and high streamflows respond differently to precipitation change, but also these differences vary with water storage availability.
Yulong Zhu, Yang Zhou, Xiaorong Xu, Changqing Meng, and Yuankun Wang
Hydrol. Earth Syst. Sci. Discuss., https://doi.org/10.5194/hess-2024-25, https://doi.org/10.5194/hess-2024-25, 2024
Revised manuscript accepted for HESS
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A timely local flood forecast is an effective way to reduce casualties and economic losses. The current theoretical or numerical models play an important role in local flood forecasting, but they still cannot bridge the contradiction between high calculation accuracy, high calculation efficiency and simple operability. Therefore, this paper expects to propose a new flood forecasting model with higher computational efficiency and simpler operation.
Danny Croghan, Pertti Ala-Aho, Jeffrey Welker, Kaisa-Riikka Mustonen, Kieran Khamis, David M. Hannah, Jussi Vuorenmaa, Bjørn Kløve, and Hannu Marttila
Hydrol. Earth Syst. Sci., 28, 1055–1070, https://doi.org/10.5194/hess-28-1055-2024, https://doi.org/10.5194/hess-28-1055-2024, 2024
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The transport of dissolved organic carbon (DOC) from land into streams is changing due to climate change. We used a multi-year dataset of DOC and predictors of DOC in a subarctic stream to find out how transport of DOC varied between seasons and between years. We found that the way DOC is transported varied strongly seasonally, but year-to-year differences were less apparent. We conclude that the mechanisms of transport show a higher degree of interannual consistency than previously thought.
Jia Qin, Yongjian Ding, Faxiang Shi, Junhao Cui, Yaping Chang, Tianding Han, and Qiudong Zhao
Hydrol. Earth Syst. Sci., 28, 973–987, https://doi.org/10.5194/hess-28-973-2024, https://doi.org/10.5194/hess-28-973-2024, 2024
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The linkage between the seasonal hydrothermal change of active layer, suprapermafrost groundwater, and surface runoff, which has been regarded as a “black box” in hydrological analyses and simulations, is a bottleneck problem in permafrost hydrological studies. Based on field observations, this study identifies seasonal variations and causes of suprapermafrost groundwater. The linkages and framework of watershed hydrology responding to the freeze–thaw of the active layer also are explored.
Francesc Gallart, Sebastián González-Fuentes, and Pilar Llorens
Hydrol. Earth Syst. Sci., 28, 229–239, https://doi.org/10.5194/hess-28-229-2024, https://doi.org/10.5194/hess-28-229-2024, 2024
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Normally, lighter oxygen and hydrogen isotopes are preferably evaporated from a water body, which becomes enriched in heavy isotopes. However, we observed that, in a water body subject to prolonged evaporation, some periods of heavy isotope depletion instead of enrichment happened. Furthermore, the usual models that describe the isotopy of evaporating waters may be in error if the atmospheric conditions of temperature and relative humidity are time-averaged instead of evaporation flux-weighted.
Guotao Zhang, Peng Cui, Carlo Gualtieri, Nazir Ahmed Bazai, Xueqin Zhang, and Zhengtao Zhang
Hydrol. Earth Syst. Sci., 27, 3005–3020, https://doi.org/10.5194/hess-27-3005-2023, https://doi.org/10.5194/hess-27-3005-2023, 2023
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This study used identified stormflow thresholds as a diagnostic tool to characterize abrupt variations in catchment emergent patterns pre- and post-earthquake. Earthquake-induced landslides with spatial heterogeneity and temporally undulating recovery increase the hydrologic nonstationary; thus, large post-earthquake floods are more likely to occur. This study contributes to mitigation and adaptive strategies for unpredictable hydrologic regimes triggered by abrupt natural disturbances.
Hongkai Gao, Fabrizio Fenicia, and Hubert H. G. Savenije
Hydrol. Earth Syst. Sci., 27, 2607–2620, https://doi.org/10.5194/hess-27-2607-2023, https://doi.org/10.5194/hess-27-2607-2023, 2023
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It is a deeply rooted perception that soil is key in hydrology. In this paper, we argue that it is the ecosystem, not the soil, that is in control of hydrology. Firstly, in nature, the dominant flow mechanism is preferential, which is not particularly related to soil properties. Secondly, the ecosystem, not the soil, determines the land–surface water balance and hydrological processes. Moving from a soil- to ecosystem-centred perspective allows more realistic and simpler hydrological models.
Daniel T. Myers, Darren L. Ficklin, and Scott M. Robeson
Hydrol. Earth Syst. Sci., 27, 1755–1770, https://doi.org/10.5194/hess-27-1755-2023, https://doi.org/10.5194/hess-27-1755-2023, 2023
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We projected climate change impacts to rain-on-snow (ROS) melt events in the Great Lakes Basin. Decreases in snowpack limit future ROS melt. Areas with mean winter/spring air temperatures near freezing are most sensitive to ROS changes. The projected proportion of total monthly snowmelt from ROS decreases. The timing for ROS melt is projected to be 2 weeks earlier by the mid-21st century and affects spring streamflow. This could affect freshwater resources management.
Sarah A. Bourke, Margaret Shanafield, Paul Hedley, Sarah Chapman, and Shawan Dogramaci
Hydrol. Earth Syst. Sci., 27, 809–836, https://doi.org/10.5194/hess-27-809-2023, https://doi.org/10.5194/hess-27-809-2023, 2023
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Here we present a hydrological framework for understanding the mechanisms supporting the persistence of water in pools along non-perennial rivers. Pools may collect water after rainfall events, be supported by water stored within the river channel sediments, or receive inflows from regional groundwater. These hydraulic mechanisms can be identified using a range of diagnostic tools (critiqued herein). We then apply this framework in north-west Australia to demonstrate its value.
Louisa D. Oldham, Jim Freer, Gemma Coxon, Nicholas Howden, John P. Bloomfield, and Christopher Jackson
Hydrol. Earth Syst. Sci., 27, 761–781, https://doi.org/10.5194/hess-27-761-2023, https://doi.org/10.5194/hess-27-761-2023, 2023
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Water can move between river catchments via the subsurface, termed intercatchment groundwater flow (IGF). We show how a perceptual model of IGF can be developed with relatively simple geological interpretation and data requirements. We find that IGF dynamics vary in space, correlated to the dominant underlying geology. We recommend that IGF
loss functionsmay be used in conceptual rainfall–runoff models but should be supported by perceptualisation of IGF processes and connectivities.
Carolin Winter, Tam V. Nguyen, Andreas Musolff, Stefanie R. Lutz, Michael Rode, Rohini Kumar, and Jan H. Fleckenstein
Hydrol. Earth Syst. Sci., 27, 303–318, https://doi.org/10.5194/hess-27-303-2023, https://doi.org/10.5194/hess-27-303-2023, 2023
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The increasing frequency of severe and prolonged droughts threatens our freshwater resources. While we understand drought impacts on water quantity, its effects on water quality remain largely unknown. Here, we studied the impact of the unprecedented 2018–2019 drought in Central Europe on nitrate export in a heterogeneous mesoscale catchment in Germany. We show that severe drought can reduce a catchment's capacity to retain nitrogen, intensifying the internal pollution and export of nitrate.
Keirnan Fowler, Murray Peel, Margarita Saft, Tim J. Peterson, Andrew Western, Lawrence Band, Cuan Petheram, Sandra Dharmadi, Kim Seong Tan, Lu Zhang, Patrick Lane, Anthony Kiem, Lucy Marshall, Anne Griebel, Belinda E. Medlyn, Dongryeol Ryu, Giancarlo Bonotto, Conrad Wasko, Anna Ukkola, Clare Stephens, Andrew Frost, Hansini Gardiya Weligamage, Patricia Saco, Hongxing Zheng, Francis Chiew, Edoardo Daly, Glen Walker, R. Willem Vervoort, Justin Hughes, Luca Trotter, Brad Neal, Ian Cartwright, and Rory Nathan
Hydrol. Earth Syst. Sci., 26, 6073–6120, https://doi.org/10.5194/hess-26-6073-2022, https://doi.org/10.5194/hess-26-6073-2022, 2022
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Recently, we have seen multi-year droughts tending to cause shifts in the relationship between rainfall and streamflow. In shifted catchments that have not recovered, an average rainfall year produces less streamflow today than it did pre-drought. We take a multi-disciplinary approach to understand why these shifts occur, focusing on Australia's over-10-year Millennium Drought. We evaluate multiple hypotheses against evidence, with particular focus on the key role of groundwater processes.
Günter Blöschl
Hydrol. Earth Syst. Sci., 26, 5015–5033, https://doi.org/10.5194/hess-26-5015-2022, https://doi.org/10.5194/hess-26-5015-2022, 2022
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There is serious concern that river floods are increasing. Starting from explanations discussed in public, the article addresses three hypotheses: land-use change, hydraulic structures, and climate change increase floods. This review finds that all three changes have the potential to not only increase floods, but also to reduce them. It is crucial to consider all three factors of change in flood risk management and communicate them to the general public in a nuanced way.
Amar Halifa-Marín, Miguel A. Torres-Vázquez, Enrique Pravia-Sarabia, Marc Lemus-Canovas, Pedro Jiménez-Guerrero, and Juan Pedro Montávez
Hydrol. Earth Syst. Sci., 26, 4251–4263, https://doi.org/10.5194/hess-26-4251-2022, https://doi.org/10.5194/hess-26-4251-2022, 2022
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Near-natural Iberian water resources have suddenly decreased since the 1980s. These declines have been promoted by the weakening (enhancement) of wintertime precipitation (the NAOi) in the most humid areas, whereas afforestation and drought intensification have played a crucial role in semi-arid areas. Future water management would benefit from greater knowledge of North Atlantic climate variability and reforestation/afforestation processes in semi-arid catchments.
José L. J. Ledesma, Anna Lupon, Eugènia Martí, and Susana Bernal
Hydrol. Earth Syst. Sci., 26, 4209–4232, https://doi.org/10.5194/hess-26-4209-2022, https://doi.org/10.5194/hess-26-4209-2022, 2022
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We studied a small stream located in a Mediterranean forest. Our goal was to understand how stream flow and the presence of riparian forests, which grow in flat banks near the stream, influence the availability of food for aquatic microorganisms. High flows were associated with higher amounts of food because rainfall episodes transfer it from the surrounding sources, particularly riparian forests, to the stream. Understanding how ecosystems work is essential to better manage natural resources.
Nils Hinrich Kaplan, Theresa Blume, and Markus Weiler
Hydrol. Earth Syst. Sci., 26, 2671–2696, https://doi.org/10.5194/hess-26-2671-2022, https://doi.org/10.5194/hess-26-2671-2022, 2022
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This study is analyses how characteristics of precipitation events and soil moisture and temperature dynamics during these events can be used to model the associated streamflow responses in intermittent streams. The models are used to identify differences between the dominant controls of streamflow intermittency in three distinct geologies of the Attert catchment, Luxembourg. Overall, soil moisture was found to be the most important control of intermittent streamflow in all geologies.
Saritha Padiyedath Gopalan, Adisorn Champathong, Thada Sukhapunnaphan, Shinichiro Nakamura, and Naota Hanasaki
Hydrol. Earth Syst. Sci., 26, 2541–2560, https://doi.org/10.5194/hess-26-2541-2022, https://doi.org/10.5194/hess-26-2541-2022, 2022
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The modelling of diversion canals using hydrological models is important because they play crucial roles in water management. Therefore, we developed a simplified canal diversion scheme and implemented it into the H08 global hydrological model. The developed diversion scheme was validated in the Chao Phraya River basin, Thailand. Region-specific validation results revealed that the H08 model with the diversion scheme could effectively simulate the observed flood diversion pattern in the basin.
Günter Blöschl
Hydrol. Earth Syst. Sci., 26, 2469–2480, https://doi.org/10.5194/hess-26-2469-2022, https://doi.org/10.5194/hess-26-2469-2022, 2022
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Sound understanding of how floods come about allows for the development of more reliable flood management tools that assist in mitigating their negative impacts. This article reviews river flood generation processes and flow paths across space scales, starting from water movement in the soil pores and moving up to hillslopes, catchments, regions and entire continents. To assist model development, there is a need to learn from observed patterns of flood generation processes at all spatial scales.
Jeenu Mathai and Pradeep P. Mujumdar
Hydrol. Earth Syst. Sci., 26, 2019–2033, https://doi.org/10.5194/hess-26-2019-2022, https://doi.org/10.5194/hess-26-2019-2022, 2022
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With availability of large samples of data in catchments, it is necessary to develop indices that describe the streamflow processes. This paper describes new indices applicable for the rising and falling limbs of streamflow hydrographs. The indices provide insights into the drivers of the hydrographs. The novelty of the work is on differentiating hydrographs by their time irreversibility property and offering an alternative way to recognize primary drivers of streamflow hydrographs.
Nathan G. F. Reaver, David A. Kaplan, Harald Klammler, and James W. Jawitz
Hydrol. Earth Syst. Sci., 26, 1507–1525, https://doi.org/10.5194/hess-26-1507-2022, https://doi.org/10.5194/hess-26-1507-2022, 2022
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The Budyko curve emerges globally from the behavior of multiple catchments. Single-parameter Budyko equations extrapolate the curve concept to individual catchments, interpreting curves and parameters as representing climatic and biophysical impacts on water availability, respectively. We tested these two key components theoretically and empirically, finding that catchments are not required to follow Budyko curves and usually do not, implying the parametric framework lacks predictive ability.
Clemens Messerschmid and Amjad Aliewi
Hydrol. Earth Syst. Sci., 26, 1043–1061, https://doi.org/10.5194/hess-26-1043-2022, https://doi.org/10.5194/hess-26-1043-2022, 2022
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Temporal distribution of groundwater recharge has been widely studied; yet, much less attention has been paid to its spatial distribution. Based on a previous study of field-measured and modelled formation-specific recharge in the Mediterranean, this paper differentiates annual recharge coefficients in a novel approach and basin classification framework for physical features such as lithology, soil and LU/LC characteristics, applicable also in other previously ungauged basins around the world.
Thea Wingfield, Neil Macdonald, Kimberley Peters, and Jack Spees
Hydrol. Earth Syst. Sci., 25, 6239–6259, https://doi.org/10.5194/hess-25-6239-2021, https://doi.org/10.5194/hess-25-6239-2021, 2021
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Human activities are causing greater and more frequent floods. Natural flood management (NFM) uses processes of the water cycle to slow the flow of rainwater, bringing together land and water management. Despite NFM's environmental and social benefits, it is yet to be widely adopted. Two environmental practitioner groups collaborated to produce a picture of the barriers to delivery, showing that there is a perceived lack of support from government and the public for NFM.
Katharina Blaurock, Burkhard Beudert, Benjamin S. Gilfedder, Jan H. Fleckenstein, Stefan Peiffer, and Luisa Hopp
Hydrol. Earth Syst. Sci., 25, 5133–5151, https://doi.org/10.5194/hess-25-5133-2021, https://doi.org/10.5194/hess-25-5133-2021, 2021
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Dissolved organic carbon (DOC) is an important part of the global carbon cycle with regards to carbon storage, greenhouse gas emissions and drinking water treatment. In this study, we compared DOC export of a small, forested catchment during precipitation events after dry and wet preconditions. We found that the DOC export from areas that are usually important for DOC export was inhibited after long drought periods.
Michael Stoelzle and Lina Stein
Hydrol. Earth Syst. Sci., 25, 4549–4565, https://doi.org/10.5194/hess-25-4549-2021, https://doi.org/10.5194/hess-25-4549-2021, 2021
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We found with a scientific paper survey (~ 1000 papers) that 45 % of the papers used rainbow color maps or red–green visualizations. Those rainbow visualizations, although attracting the media's attention, will not be accessible for up to 10 % of people due to color vision deficiency. The rainbow color map distorts and misleads scientific communication. The study gives guidance on how to avoid, improve and trust color and how the flaws of the rainbow color map should be communicated in science.
Tingting Ning, Zhi Li, Qi Feng, Zongxing Li, and Yanyan Qin
Hydrol. Earth Syst. Sci., 25, 3455–3469, https://doi.org/10.5194/hess-25-3455-2021, https://doi.org/10.5194/hess-25-3455-2021, 2021
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Previous studies decomposed ET variance in precipitation, potential ET, and total water storage changes based on Budyko equations. However, the effects of snowmelt and vegetation changes have not been incorporated in snow-dependent basins. We thus extended this method in arid alpine basins of northwest China and found that ET variance is primarily controlled by rainfall, followed by coupled rainfall and vegetation. The out-of-phase seasonality between rainfall and snowmelt weaken ET variance.
Lovrenc Pavlin, Borbála Széles, Peter Strauss, Alfred Paul Blaschke, and Günter Blöschl
Hydrol. Earth Syst. Sci., 25, 2327–2352, https://doi.org/10.5194/hess-25-2327-2021, https://doi.org/10.5194/hess-25-2327-2021, 2021
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We compared the dynamics of streamflow, groundwater and soil moisture to investigate how different parts of an agricultural catchment in Lower Austria are connected. Groundwater is best connected around the stream and worse uphill, where groundwater is deeper. Soil moisture connectivity increases with increasing catchment wetness but is not influenced by spatial position in the catchment. Groundwater is more connected to the stream on the seasonal scale compared to the event scale.
William Rust, Mark Cuthbert, John Bloomfield, Ron Corstanje, Nicholas Howden, and Ian Holman
Hydrol. Earth Syst. Sci., 25, 2223–2237, https://doi.org/10.5194/hess-25-2223-2021, https://doi.org/10.5194/hess-25-2223-2021, 2021
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In this paper, we find evidence for the cyclical behaviour (on a 7-year basis) in UK streamflow records that match the main cycle of the North Atlantic Oscillation. Furthermore, we find that the strength of these 7-year cycles in streamflow is dependent on proportional contributions from groundwater and the response times of the underlying groundwater systems. This may allow for improvements to water management practices through better understanding of long-term streamflow behaviour.
Elnaz Azmi, Uwe Ehret, Steven V. Weijs, Benjamin L. Ruddell, and Rui A. P. Perdigão
Hydrol. Earth Syst. Sci., 25, 1103–1115, https://doi.org/10.5194/hess-25-1103-2021, https://doi.org/10.5194/hess-25-1103-2021, 2021
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Computer models should be as simple as possible but not simpler. Simplicity refers to the length of the model and the effort it takes the model to generate its output. Here we present a practical technique for measuring the latter by the number of memory visits during model execution by
Strace, a troubleshooting and monitoring program. The advantage of this approach is that it can be applied to any computer-based model, which facilitates model intercomparison.
Sheena A. Spencer, Axel E. Anderson, Uldis Silins, and Adrian L. Collins
Hydrol. Earth Syst. Sci., 25, 237–255, https://doi.org/10.5194/hess-25-237-2021, https://doi.org/10.5194/hess-25-237-2021, 2021
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We used unique chemical signatures of precipitation, hillslope soil water, and groundwater sources of streamflow to explore seasonal variation in runoff generation in a snow-dominated mountain watershed underlain by glacial till and permeable bedrock. Reacted hillslope water reached the stream first at the onset of snowmelt, followed by a dilution effect by snowmelt from May to June. Groundwater and riparian water were important sources later in the summer. Till created complex subsurface flow.
Tian Lan, Kairong Lin, Chong-Yu Xu, Zhiyong Liu, and Huayang Cai
Hydrol. Earth Syst. Sci., 24, 5859–5874, https://doi.org/10.5194/hess-24-5859-2020, https://doi.org/10.5194/hess-24-5859-2020, 2020
Dan Rosbjerg
Hydrol. Earth Syst. Sci., 24, 4575–4585, https://doi.org/10.5194/hess-24-4575-2020, https://doi.org/10.5194/hess-24-4575-2020, 2020
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August Colding contributed the first law of thermodynamics, evaporation from water and grass, steady free surfaces in conduits, the cross-sectional velocity distribution in conduits, a complete theory for the Gulf Stream, air speed in cyclones, the piezometric surface in confined aquifers, the unconfined elliptic water table in soil between drain pipes, and the wind-induced set-up in the sea during storms.
Zhengke Pan, Pan Liu, Chong-Yu Xu, Lei Cheng, Jing Tian, Shujie Cheng, and Kang Xie
Hydrol. Earth Syst. Sci., 24, 4369–4387, https://doi.org/10.5194/hess-24-4369-2020, https://doi.org/10.5194/hess-24-4369-2020, 2020
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This study aims to identify the response of catchment water storage capacity (CWSC) to meteorological drought by examining the changes of hydrological-model parameters after drought events. This study improves our understanding of possible changes in the CWSC induced by a prolonged meteorological drought, which will help improve our ability to simulate the hydrological system under climate change.
Zong-Jie Li, Zong-Xing Li, Ling-Ling Song, Juan Gui, Jian Xue, Bai Juan Zhang, and Wen De Gao
Hydrol. Earth Syst. Sci., 24, 4169–4187, https://doi.org/10.5194/hess-24-4169-2020, https://doi.org/10.5194/hess-24-4169-2020, 2020
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This study mainly explores the hydraulic relations, recharge–drainage relations and their transformation paths, and the processes of each water body. It determines the composition of runoff, quantifies the contribution of each runoff component to different types of tributaries, and analyzes the hydrological effects of the temporal and spatial variation in runoff components. More importantly, we discuss the hydrological significance of permafrost and hydrological processes.
Michal Jenicek and Ondrej Ledvinka
Hydrol. Earth Syst. Sci., 24, 3475–3491, https://doi.org/10.5194/hess-24-3475-2020, https://doi.org/10.5194/hess-24-3475-2020, 2020
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Changes in snow affect the runoff seasonality, including summer low flows. Here we analyse this effect in 59 mountain catchments in Czechia. We show that snow is more effective in generating runoff compared to rain. Snow-poor years generated lower groundwater recharge than snow-rich years, which resulted in higher deficit volumes in summer. The lower recharge and runoff in the case of a snowfall-to-rain transition due to air temperature increase might be critical for water supply in the future.
Julia L. A. Knapp, Jana von Freyberg, Bjørn Studer, Leonie Kiewiet, and James W. Kirchner
Hydrol. Earth Syst. Sci., 24, 2561–2576, https://doi.org/10.5194/hess-24-2561-2020, https://doi.org/10.5194/hess-24-2561-2020, 2020
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Changes of stream water chemistry in response to discharge changes provide important insights into the storage and release of water from the catchment. Here we investigate the variability in concentration–discharge relationships among different solutes and hydrologic events and relate it to catchment conditions and dominant water sources.
Elizabeth R. Jachens, David E. Rupp, Clément Roques, and John S. Selker
Hydrol. Earth Syst. Sci., 24, 1159–1170, https://doi.org/10.5194/hess-24-1159-2020, https://doi.org/10.5194/hess-24-1159-2020, 2020
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Recession analysis uses the receding streamflow following precipitation events to estimate watershed-average properties. Two methods for recession analysis use recession events individually or all events collectively. Using synthetic case studies, this paper shows that analyzing recessions collectively produces flawed interpretations. Moving forward, recession analysis using individual recessions should be used to describe the average and variability of watershed behavior.
Lu Lin, Man Gao, Jintao Liu, Jiarong Wang, Shuhong Wang, Xi Chen, and Hu Liu
Hydrol. Earth Syst. Sci., 24, 1145–1157, https://doi.org/10.5194/hess-24-1145-2020, https://doi.org/10.5194/hess-24-1145-2020, 2020
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In this paper, recession flow analysis – assuming nonlinearized outflow from aquifers into streams – was used to quantify active groundwater storage in a headwater catchment with high glacierization and large-scale frozen ground on the Tibetan Plateau. Hence, this work provides a perspective to clarify the impact of glacial retreat and frozen ground degradation due to climate change on hydrological processes.
Francesc Gallart, Jana von Freyberg, María Valiente, James W. Kirchner, Pilar Llorens, and Jérôme Latron
Hydrol. Earth Syst. Sci., 24, 1101–1107, https://doi.org/10.5194/hess-24-1101-2020, https://doi.org/10.5194/hess-24-1101-2020, 2020
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How catchments store and release rain or melting water is still not well known. Now, it is broadly accepted that most of the water in streams is older than several months, and a relevant part may be many years old. But the age of water depends on the stream regime, being usually younger during high flows. This paper tries to provide tools for better analysing how the age of waters varies with flow in a catchment and for comparing the behaviour of catchments diverging in climate, size and regime.
Sebastian J. Gnann, Nicholas J. K. Howden, and Ross A. Woods
Hydrol. Earth Syst. Sci., 24, 561–580, https://doi.org/10.5194/hess-24-561-2020, https://doi.org/10.5194/hess-24-561-2020, 2020
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In many places, seasonal variability in precipitation and evapotranspiration (climate) leads to seasonal variability in river flow (streamflow). In this work, we explore how climate seasonality is transformed into streamflow seasonality and what controls this transformation (e.g. climate aridity and geology). The results might be used in grouping catchments, predicting the seasonal streamflow regime in ungauged catchments, and building hydrological simulation models.
Adam S. Ward, Steven M. Wondzell, Noah M. Schmadel, Skuyler Herzog, Jay P. Zarnetske, Viktor Baranov, Phillip J. Blaen, Nicolai Brekenfeld, Rosalie Chu, Romain Derelle, Jennifer Drummond, Jan H. Fleckenstein, Vanessa Garayburu-Caruso, Emily Graham, David Hannah, Ciaran J. Harman, Jase Hixson, Julia L. A. Knapp, Stefan Krause, Marie J. Kurz, Jörg Lewandowski, Angang Li, Eugènia Martí, Melinda Miller, Alexander M. Milner, Kerry Neil, Luisa Orsini, Aaron I. Packman, Stephen Plont, Lupita Renteria, Kevin Roche, Todd Royer, Catalina Segura, James Stegen, Jason Toyoda, Jacqueline Hager, and Nathan I. Wisnoski
Hydrol. Earth Syst. Sci., 23, 5199–5225, https://doi.org/10.5194/hess-23-5199-2019, https://doi.org/10.5194/hess-23-5199-2019, 2019
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The movement of water and solutes between streams and their shallow, connected subsurface is important to many ecosystem functions. These exchanges are widely expected to vary with stream flow across space and time, but these assumptions are seldom tested across basin scales. We completed more than 60 experiments across a 5th-order river basin to document these changes, finding patterns in space but not time. We conclude space-for-time and time-for-space substitutions are not good assumptions.
Lucy J. Barker, Jamie Hannaford, Simon Parry, Katie A. Smith, Maliko Tanguy, and Christel Prudhomme
Hydrol. Earth Syst. Sci., 23, 4583–4602, https://doi.org/10.5194/hess-23-4583-2019, https://doi.org/10.5194/hess-23-4583-2019, 2019
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It is important to understand historic droughts in order to plan and prepare for possible future events. In this study we use the standardised streamflow index for 1891–2015 to systematically identify, characterise and rank hydrological drought events for 108 near-natural UK catchments. Results show when and where the most severe events occurred and describe events of the early 20th century, providing catchment-scale detail important for both science and planning applications of the future.
Ralf Loritz, Axel Kleidon, Conrad Jackisch, Martijn Westhoff, Uwe Ehret, Hoshin Gupta, and Erwin Zehe
Hydrol. Earth Syst. Sci., 23, 3807–3821, https://doi.org/10.5194/hess-23-3807-2019, https://doi.org/10.5194/hess-23-3807-2019, 2019
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In this study, we develop a topographic index explaining hydrological similarity within a energy-centered framework, with the observation that the majority of potential energy is dissipated when rainfall becomes runoff.
Sophie Ehrhardt, Rohini Kumar, Jan H. Fleckenstein, Sabine Attinger, and Andreas Musolff
Hydrol. Earth Syst. Sci., 23, 3503–3524, https://doi.org/10.5194/hess-23-3503-2019, https://doi.org/10.5194/hess-23-3503-2019, 2019
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This study shows quantitative and temporal offsets between nitrogen input and riverine output, using time series of three nested catchments in central Germany. The riverine concentrations show lagged reactions to the input, but at the same time exhibit strong inter-annual changes in the relationship between riverine discharge and concentration. The study found a strong retention of nitrogen that is dominantly assigned to a hydrological N legacy, which will affect future stream concentrations.
Davide Zoccatelli, Francesco Marra, Moshe Armon, Yair Rinat, James A. Smith, and Efrat Morin
Hydrol. Earth Syst. Sci., 23, 2665–2678, https://doi.org/10.5194/hess-23-2665-2019, https://doi.org/10.5194/hess-23-2665-2019, 2019
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This study presents a comparison of flood properties over multiple Mediterranean and desert catchments. While in Mediterranean areas floods are related to rainfall amount, in deserts we observed a strong connection with the characteristics of the more intense part of storms. Because of the different mechanisms involved, despite having significantly shorter and more localized storms, deserts are able to produce floods with a magnitude comparable to Mediterranean areas.
Martina Botter, Paolo Burlando, and Simone Fatichi
Hydrol. Earth Syst. Sci., 23, 1885–1904, https://doi.org/10.5194/hess-23-1885-2019, https://doi.org/10.5194/hess-23-1885-2019, 2019
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The study focuses on the solute export from rivers with the purpose of discerning the impacts of anthropic activities and catchment characteristics on water quality. The results revealed a more detectable impact of the anthropic activities than of the catchment characteristics. The solute export follows different dynamics depending on catchment characteristics and mainly on solute-specific properties. The export modality is consistent across different catchments only for a minority of solutes.
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Short summary
The evaluation of model performance is essential for hydrological modeling. Using performance criteria requires a deep understanding of their properties. We focus on a counterintuitive aspect of the Nash–Sutcliffe efficiency (NSE) and show that if we divide the data into multiple parts, the overall performance can be higher than all the evaluations of the subsets. Although this follows from the definition of the NSE, the resulting behavior can have unintended consequences in practice.
The evaluation of model performance is essential for hydrological modeling. Using performance...
