bluuebunny/crossref_metadata_2025 huggingface dataset:
Geological History of Nott Corona, Isabella Quadrangle (V-50), Venus
Authors: Hadimi Ismail , El bilali Hafida , Ernst Richard , youbi Nasrrddine
Published: September 2022

Nott Corona is within Isabella Quadrangle (V-50), located 3000 km south of Atla Regio, east of Aditi Dorsa, southwest of Wawalag Planitia, and north of Nsomeka Planitia. Nott Corona has a central depression with dimensions of 110 x 80 km and a depth of about 250 m. Nott Corona has been described in the initial reconnaissance mapping of Quadrangle V-50 (e.g., [1-2]), and briefly discussed in [3]. Isabella (175 km diameter) is the second-largest impact crater on Venus and has been previously characterized in detail [4].

The region has abundant magmatic features in addition to Nott Corona: Epon Corona, Libby Patera, Tursa Tholus, as well as graben-fissure systems. We have selected the Nott corona region for detailed (1:500,000 scale) geological mapping to produce a geological history that integrates the volcanic features (lava flows and magmatic centres) along with graben fissure systems interpreted to overlie dyke swarms (c.f. [5]).

The focus of this abstract is our detailed mapping of the radiating graben-fissure systems in the region, and grouping of these into different swarms. Our mapping reveals the impressive radiating swarm associated with Nott corona and additional centres, and also circumferential swarms associated with Libby Patera and Epona corona, as well as additional linear swarms whose source is not yet identified, but could belong to giant radiating swarms fed from distal magmatic centres outside the study area.

Future mapping in this area will focus on detailed mapping (1:500,000 scale) of the flows to determine their history and identify their magmatic sources, whether fissure-fed from dykes (circumferential or radial) or fed from inferred small magma chambers marked by surface collapse features [6], or fed from circular fractures associated with caldera collapse [6, 7].

 

References: [1] Bleamaster L.F. (2006) 37th LPSC, Abstract # 2233. [2] Bleamaster L.F. (2008) Abstr. Ann. Mtg. Planet. Geol. Mappers.  [3] Basilevsky A.T., et al. (2009) 40th LPSC, Abstract # 1827. [4] Miyamoto H., Sasaki, S. (2000) Icarus, 145, 533-545. [5] Buchan K.L. and Ernst R.E. (2021). Gond. Res., 100, 25-43.  [6] MacLellan L.M., et al. (2021). Earth-Sci. Rev., 220. 103619. [7] El Bilali H., et al. (2021). 52nd LPSC, Abstract No. 2529.
The oscillatory motion of the polar cyclones of Jupiter results from vorticity dynamics
Authors: Gavriel Nimrod , Kaspi Yohai
Published: September 2022

The polar cyclone at Jupiter's south pole and the 5 cyclones surrounding it oscillate in position and interact. These cyclones, observed since 2016 by NASA's Juno mission, present a unique opportunity to study vortex dynamics and interactions on long time scales. The cyclones' position data, acquired by Juno's JIRAM, is analyzed, showing dominant oscillations with ~12-month periods and amplitudes of ~400 km. Here, the mechanism driving these oscillations is revealed by considering vorticity-gradient forces generated by mutual interactions between the cyclones and the latitudinal variation in planetary vorticity. Data-driven estimation of these forces exhibits a high correlation with the measured acceleration of the cyclones. To further test this mechanism, a model is constructed, simulating how cyclones subject to these forces exhibit similar oscillatory motion. 
Heterogeneous Reactivity in the Atmosphere of Rocky Planets
Authors: Lasne Jerome
Published: September 2022

The current context of space exploration missions is extremely favourable, especially regarding rocky planets. Several orbiters and rovers currently investigate the surface and atmosphere of Mars; more are planned in the future. Three Medium-class missions have been approved by NASA and ESA to study Venus in the coming years. Space telescopes, recently launched or scheduled, will be able to determine the composition of exoplanet atmospheres. Rocky (exo)planets are preferred targets, because they hold similarities with our own planet. Past and present signs of habitability are eagerly scrutinized, in the first place as atmospheric biomarkers.

Descriptions of planetary atmospheres based on gas-phase (homogeneous) chemistry are globally robust. Nonetheless, recent key detections remain hotly debated, in part because they remain unexplained by gas-phase chemistry alone. The most illustrative example of this is the controversial detection of methane on Mars. Recent work has shown that this apparent contradiction may be lifted by heterogeneous photo-induced reactions1.

Different types of aerosols exist in planetary atmospheres: dust, clouds, hazes,… They exist as liquids and solids, depending on the physical and chemical parameters (T, P, chemical composition) characterizing the atmosphere. Models of planetary atmospheres usually describe gas-phase reactions and photochemistry, but overlook heterogeneous reactions. Meanwhile, these interactions are key to account for crucial atmospheric processes; the most famous example of this is the “hole” in the stratospheric ozone layer of our planet.

In this talk, I will focus on heterogeneous processes on solid surfaces, and on their influence on the atmosphere of rocky bodies. Mineral dust and ice surfaces represent chemical factories for reactions to take place. Important heterogeneous reactions are known in the atmosphere of Earth, but heterogeneous chemistry is an (almost) virgin field when it goes to other planets. This talk will be an opportunity to discuss the current knowledge on atmospheric heterogeneous processes, which will be illustrated with recent examples. The need for dedicated experimental setups to study heterogeneous reactions under conditions of relevance for planetary atmospheres will be stressed, and perspectives for the study of exoplanets will be drawn2.

 

1 Zhang, X. et al., Icarus 376, Article number 114832 (2022)

2 Lasne, J. ACS Earth Space Chem. 5, 149 (2021)
Temporal evolution and spatial variation of the solar wind structures throughout the heliosphere
Authors: Timar Aniko , Opitz Andrea , Biro Nikolett , Dalya Zsuzsanna , Koban Gergely , Nemeth Zoltan , Madar Akos
Published: September 2022

In order to improve the predictions of the solar wind environment at planets, moons, comets and interplanetary spacecraft, we study the temporal evolution and spatial variation of solar wind structures. Special emphasis is put on the fast and slow solar wind stream interaction regions (SIRs or CIRs). Currently, a huge fleet of solar observatories is available throughout the inner heliosphere, hence a multi-spacecraft study of the propagation and evolution of these structures is possible. We improve solar wind predictions by removing ICME signatures from the input data to reduce the number of false alarms. Ballistic radial propagation models are refined by pressure correction at CIRs. Latitudinal effects are taken into account to improve the models and to extend our predictions to three dimensions.
Imaginäre Naturverhältnisse: Psychoanalytische Einsichten zur Herstellung ontologischer Sicherheit in Berlin, Vancouver und Singapur
Authors: Pohl Lucas , Helbrecht Ilse
Published: September 2022

Abstract. A central diagnosis driving research around social relations of
nature is the thesis of the “end of nature”. In an era marked by climate
change and global warming, the image of nature as a pristine and stable
foundation of human existence seems outdated. In light of this, recent
scholarship demonstrates how environmental changes and conflicts
increasingly affect people's daily lives and present significant threats to
psychic well-being. In contrast, in this paper we investigate the conditions
under which nature continues to function as an effective source of
`ontological security'. As part of an international comparative research
project that engages geographical imaginaries of security and insecurity in
Berlin, Vancouver, and Singapore, we analyze how nature is imagined by city
dwellers as an object of desire that offers a place of refuge to escape the
burdens from urban everyday life. Against this background, we emphasize
imaginary nature as a powerful everyday source for the ontological security
of subjects even under today's postnatural conditions.
23 UPH in Africa, process and progress
Authors: Mahé Gil , Ogilvie Andrew
Published: September 2022

Following the 23 Unsolved Problems in Hydrology paper (Blöschl et al. 2019), we launched the "23 UPH in Africa" initiative in collaboration with the UNESCO/IHP FRIEND-Water Programme, the ICIREWARD UNESCO Cat 2 Centre of Montpellier and the IAHS-ICSW commission. This consultation aims to identify and review the considerable research coming out of Africa lately, and put forward the contribution of the African academic community to advancing key unsolved problems in hydrology.

So far, more than 400 colleagues working in 26 countries registered their interest, and filled in a brief online questionnaire, created to gather and synthesise key information about interested participants. A call for volunteers led to selecting 42 colleagues to coordinate discussions within the seven UPH themes and 23 questions. Using online platforms and collaborative tools, these working groups seek to highlight essential research and results from Africa contributing to the 23 UPH. The synthesis also underlines the specific insights and advances related to the African physical and socio-economic environment, as well as priority and emerging questions from the continent.
Saline intrusion through zones of high hydraulic conductivity associated with faults in coastal aquifers
Authors: Alves Rafaela , Lucena Leandson
Published: September 2022

Coastal aquifers are subject to contamination by saline intrusion in several regions of the world, notably in urban regions or near them, and the increase in demand for this resource aggravates this problem. In addition to this scenario, the presence of neotectonic faults implies an increase in the heterogeneity of the hydrogeological environment, which is reflected in variations in saturated thickness, hydraulic conductivity and exploited flow rates. In the east coast of northeastern Brazil, the Barreiras Aquifer, unconfined, compartmentalized by faults and, due to its high importance for regional water supply, is widely submitted to high rates of exploited flow. In this context, the objective of this research is to contribute to a better understanding on how a saline intrusion contamination can develop in the coastal aquifer, seeing that the main faults, these with a predominantly transtensional (striking NW-SE) and horizontal transcurrent (striking NE-SW) kinematic character, present themselves as zones of high hydraulic conductivities. The methods used consist of two-dimensional resistivity cross-section and a numerical model of dependent density flow using the SEAWAT software USGS. The 2D resistivity model allowed to characterize the fault locally and to support the construction of the numerical model by corroborating with the fault zone as a zone of high relative hydraulic and geoeletric conductivity. The simulations performed in the model developed in SEAWAT over 20 years reveal that there is a difference between the advance of contamination between faults. These results can be explained by the kinematic character. Variations in aquifer recharge between dry and rainy periods also show differences in the advance of saline intrusion. Therefore, there is a need for further research in these environments, seeking to develop an efficient management of water resources.

Keywords: coastal aquifers, faults, heterogeneity, hydraulic conductivity, saline intrusion, SEAWAT software.
Feasibility assessment of MAR
Authors: Merritt Wendy , Guillaume Joseph , Harvey Natasha , Ticehurst Jenifer , Croke Barry
Published: September 2022

This presentation gives an overview of an investigation of the potential for managed aquifer recharge (MAR) in three established or emerging irrigated cotton-growing regions in Australia: the Lower Murrumbidgee and Lower Namoi basins in western NSW and the Gilbert River catchment in far northern Queensland. Ongoing interest in MAR as a strategy to support irrigated agriculture has not translated into much investment in Australia. The aim was to evaluate how MAR might be feasible for irrigated cotton production and associated cropping systems in the focus regions and make recommendations on next-step actions that could incrementally develop the knowledge, confidence and expertise needed to invest in MAR. The broad approach taken was to draw on evidence from a holistic feasibility assessment to scope a set of plausible scenarios for MAR, to test and refine these scenarios with local and state government stakeholders and researchers, and to develop recommendations to support any efforts to proceed with MAR by the funder (the Cotton Research and Development Corporation) or other parties.

The scenarios varied in their scale (e.g. single farm, irrigation schemes), purpose (e.g. managing drawdown, reducing evaporative losses), infrastructure and governance arrangements. Together they highlighted the critical need to improve knowledge on local hydrogeological conditions and develop MAR policy and regulations that enhance the strengths of MAR whilst minimising risks. A water accounting grade estimate of recharge is critical to being confident that MAR provides an advantage over investing in reducing infiltration “losses”, allowing an allocation to be issued. As an initial step, MAR pilot studies could work with state government to test water accounting of recharge quantification methods in dedicated trial infiltration basins and test injection wells. Reducing uncertainty about evaporation and recharge rates is critical to comparing MAR as a low loss water storage solution to other evaporation or infiltration reduction alternatives. If land managers invest in improving understanding of aquifers under their land and quantifying seepage and evaporation over time, this will incrementally reduce uncertainty on the effectiveness and viability of MAR. 
Evaluation of Meteorological Drought Characteristics under Climate Change over the Agriculture-dominated Marathwada Region, India
Authors: Swain Sabyasachi , Mishra Surendra , Pandey Ashish
Published: September 2022

Drought is one of the most precarious phenomena associated with serious repercussions, especially over the agriculture-dominated regions. This study presents an investigation of drought characteristics over the Marathwada Region, Maharashtra, India, which is infamous for a large number of farmer suicides. The monthly rainfall data for 1951-2020 is collected from Indian Meteorological Department (IMD). Two widely used drought indices, viz., Standardized Precipitation Index (SPI) and Effective Drought Index (EDI) are employed to characterize the drought events. Moreover, droughts under future climate i.e., from 2021 to 2090, are investigated using an ensemble of different CMIP5 models for the Representative Concentration Pathways (RCPs) 4.5 and 8.5. The results revealed the Marathwada Region to be prone to droughts due to a remarkable inter-annual variability in rainfall. The droughts are predicted to become more severe, frequent, and persistent in the future. From the comparative assessment of two indices, EDI is found to be superior in capturing the onset of the droughts and hence, can be handy in drought monitoring purposes. Since Marathwada Region has a monsoon-dominated climate with high agricultural importance, the information reported in this study will help devise water management strategies to minimize the repercussions of droughts. Besides, the methodology presented will encourage its replication over different regions of the world that have been affected by climate change and its ramifications, mostly in the form of frequent droughts or lower crop yields.
Time-lapse imagery to monitor ephemeral and intermittent streams 
Authors: Noto Simone , Tauro Flavia , Botter Gianluca , Grimaldi Salvatore
Published: September 2022

While the interest in ephemeral and intermittent streams increased in the last few decades, monitoring such watercourses remains a major challenge in hydrology. Direct field observations are best to detect spatial patterns of flow persistence, but they are time and labour intensive and may be impractical in difficult-to-access environments. Moreover, instrumentation deployed in the riverbed can provide information about the presence/absence of water, nevertheless these methods lack in streamflow quantification. Motivated by latest advancements in computer vision hardware and software, we proposed the development and application of a stage-camera system to monitor the water level in ungauged headwater streams. This system encompasses a camera with near infrared (NIR) night vision capabilities and a pole that serves as reference object in the collected images. To evaluate the efficacy of this system in the detection of river dynamics, a set of 22 stage-camera stations was installed along the entire river network at the 4 km2 Montecalvello catchment, near Viterbo (VT, Italy). Time-lapse imagery was processed through a computationally inexpensive algorithm featuring simple image-based operations. The feasibility of this approach is demonstrated through a set of benchmark measurements obtained from a supervised procedure. Preliminary evaluations are encouraging and support the usability of this approach in monitoring ephemeral and intermittent streams dynamics.
Copulas for hydroclimatic analysis: A practice-oriented overview
Authors: Tootoonchi Faranak , Sadegh Mojtaba , Haerter Jan Olaf , Räty Olle , Grabs Thomas , Teutschbein Claudia
Published: September 2022

A warming climate is associated with increasing hydroclimatic extremes, which are often interconnected through complex processes, prompting their concurrence and/or succession, and causing compound extreme events. It is critical to analyze the risks of compound events, given their disproportionately high adverse impacts. To account for the variability in two or more hydroclimatic variables (e.g., temperature and precipitation) and their dependence, a rising number of publications focuses on multivariate analysis, among which the notion of copula-based probability distribution has attracted tremendous interest. Copula is a mathematical function that expresses the joint cumulative probability distribution of multiple variables. Our focus is to re-emphasize the fundamental requirements and limitations of applying copulas. Confusion about these requirements may lead to misconceptions and pitfalls, which can potentially compromise the robustness of risk analyses for environmental processes and natural hazards. We conducted a systematic literature review of copulas, as a prominent tool in the arsenal of multivariate methods used for compound event analysis, and underpinned them with a hydroclimatic case study in Sweden to illustrate a practical approach to copula-based modeling. Here, we (1) provide end-users with a didactic overview of necessary requirements, statistical assumptions and consequential limitations of copulas, (2) synthesize common perceptions and practices, and (3) offer a user-friendly decision support framework to employ copulas, thereby support researchers and practitioners in addressing hydroclimatic hazards, hence demystify what can be an area of confusion.
Social uncertainty in flood risk: field research, citizens’ engagement, institutions' collaboration.
Authors: Dimitrakopoulou Dimitra , Ioannidis Romanos , Sargentis Georgios-Fivos , Dimitriadis Panayiotis , Iliopoulou Theano , Chardavellas Efthimis , Vavouloyiannis Stelios , Mamassis Nikos , Koutsoyiannis Demetris
Published: September 2022

The well-presented results and the high efficiency of new tools in the evaluation of flood risk leads us to forget the fundamental tool for analysis which is field research, citizens’ engagement and institutions collaboration.

Having in mind that field-research must be connected with modern tools, this paper shows that only engineers are appropriate for flood-study field-research. In addition, a training protocol is necessary. This protocol describes the method of the field-research, the organization of the team, legal distractions in field research, proper software needed for field research, characteristic points of interest, code name and proper depiction of the points. In addition, describes an efficient formula of the reports in order to be used in GIS and evaluated in DEM and risk analysis.

In addition, the cooperation of research and governmental institutions is crucial for the quantification of risks associated with natural hazards. Research institutions, local-government authorities and environmental agencies are all necessary, in order to combine both theoretical and practical knowledge for the generation of optimized risk-assessment results. Thus, a targeted methodology was formed including a process of successive cycles of communications relevant those agencies and institutions, aiming to utilize both their qualitative and quantitative knowledge and overall, to set a solid data-based foundation for the later stages of the flood-risk analysis.

Last but not least, in the process of investigating for locations with increased flood risk, citizens’ engagement should be sought. During the research field or through an online form, the citizens should be asked to fill in a relative questionnaire with brief, multiple choice questions, regarding their residence, their years of residence, the frequency of floods that they can recall and their location and other relates topics. The permanent residents' experience can lead to the location of areas prone to flood that cannot be located otherwise, in terms of designs. Consequently, it is argued that the residents must play an active role in the conception, design and implementation of flood protection projects and infrastructure projects, overall.
Hydrology and society: Phenomena emerging from the interactions and feedbacks between human and water systems
Authors: Di Baldassarre Giuliano , Wei Yongping , Savelli Elisa , Barendrecht Marlies , Khatami Sina , Li Xu , van Oel Pieter , O'Keeffe Jimmy , Shanono Nura Jafar , Famiglietti James S. (Jay)
Published: September 2022

Water resources management and hydrological risk reduction require anticipation of emergent (unexpected or unintended) phenomena as fundamental dynamics of complex human-water systems. Explaining and characterizing these sociohydrological phenomena is a central focus of Panta Rhei–Everything Flows, the Scientific Decade of the International Association of Hydrological Sciences (2013-2022). Here we use System Dynamics’ archetypes to describe and classify socio-hydrological phenomena emerging from nonlinear interactions between human and water systems. Archetypes illustrate dynamic behaviours that are frequently observed across (seemingly) different systems, contexts or problem settings. They include intended or unintended actions and reactions with explicit recognition of delays in reaction times. Reinforcing (or positive) and balancing (or negative) feedback loops and system boundaries are key elements for describing archetypes. In the study of human-water systems, the most common archetypes are Limits to Growth, Fixes that Backfire, Success to the Successful, and Tragedy of the Commons. Using system archetypes to generalize the phenomena in coupled human-water systems allows for the comparison among case studies along with the integration of multiple dimensions, thereby contributing to the development of new theories which provide common causes and explanations. We first present several classes of sociohydrological phenomena that have been explored over the past decade, and then discuss their role in explaining the dynamics of human-water systems. Finally, we engage with the implications for integrated water resources management, hydrological risk reduction, and water governance.
Use of data assimilation to improve rainfall-runoff model structure for climate change projections
Authors: Lerat Julien , Chiew Francis , Zheng Hongxing , Robertson David
Published: September 2022

Data assimilation is a powerful tool that has been used to correct states and parameters of rainfall-runoff models based on recent streamflow, remotely sensed soil moisture or groundwater data. Data assimilation is now routinely applied by forecasting centres around the world to improve simulations and increase forecast skill. In this work, we are less concerned with the direct benefits of data assimilation on model outputs, but more on the nature of the corrections introduced and how they can be analysed to diagnose structural deficiencies in rainfall-runoff models.

Rainfall-runoff models have been shown to lack extrapolation capacity in simulating dry and wet periods that are more extreme than calibration conditions. This is particularly concerning in the context of climate change studies where more climate extremes are generally predicted for expected. This is the case in South-Eastern Australia where annual rainfall is expected to decrease significantly under most climate scenarios. Consequently, the improvement of rainfall-runoff model structures to better simulate dry flow regimes is critical to obtain robust estimates of water resources availability.

In this work, we assimilated streamflow data in the GR2M monthly rainfall-runoff models for 100 catchments in South-East Australia. The assimilation was conducted during a wet period between 1970 to 1995 and used to identify model structure deficiencies, particularly in the function computing water exchanges with nearby catchments. An attempt of correcting these deficiencies was undertaken using a simple regression approach. Finally, the correction was applied during a dry period (1995-2010) and performance was compared with the original (uncorrected) model. The results suggest that the corrected simulations better capture streamflow extremes, especially low flows. Further work is also discussed related to the use of additional data such as LAI and groundwater data to better constrain the correction regression.
Analysis influence of evapotranspiration on superconducting gravity signal at daily time step
Authors: Loiseau Bertille , Carriere Simon , Champollion Cédric , Ollivier Chloé , Martin-StPaul Nicolas , Lesparre Nolwenn , Olioso Albert , Hinderer Jacques , Jougnot Damien
Published: September 2022

Estimating evapotranspiration (ET) is a primary challenge in modern hydrology. Hydrogravimetry is an integrative approach that provides highly precise continuous measurement of gravity acceleration. However, large-scale effects (e.g. tides, polar motion, atmospheric loading) limit the fine time-scale interpretation of this data and processing leads to residual signal noise. To circumvent this limitation, we exploited the difference between two superconducting gravimeters located 512 m apart on the same vertical. The difference calculation makes it possible to remove shared large-scale effects. Daily variation of this gravity difference is significantly correlated with daily evapotranspiration as estimated using the water balance model SimpKcET (p-value = 4.10-10). However, this approach is effective only during rain-free periods. In the future, comparison with direct ET measurements (e.g. eddy-covariance, scintillometer) may confirm and strengthen our interpretation. Improved hydrogravimetric data processing will allow to extend this approach to other experimental sites equipped with a single superconducting gravimeter.
Thermonuclear 36Cl, a new tritium-like tracer of the hydrologic cycle. Application to the water residence time in Cameroon volcanic lakes
Authors: Abba Souleyman , Hamelin Bruno , Deschamps Pierre , Ngounou Ngatcha Benjamin , Garcin Yannick , Team A.s.t.e.r
Published: September 2022

Chemical and isotopic tracers are powerful tools to study the water cycle and may constitute complementary methods in areas where instrumental records are insufficient. Tritium has been used routinely up to the 2000’s, but because of its short half-life, the bomb-3H spike of the 1960’s is today hardly distinguishable from the natural background level. Bomb-produced 36Cl offers an alternative tool, due to the conservative behavior of chloride and the large amounts of 36Cl released during the marine nuclear tests of the 1950’s.

In this study, we use the bomb-36Cl pulse to assess the residence time of water in five volcanic lakes (Mbalang, Tabere, Tizon, Gegouba and Baledjam) of the Adamawa plateau in the northern region of the Cameroon Volcanic Line. Sediment cores from Mbalang and Tizon have been studied previously for paleo-environments, but otherwise, the Adamawa lakes received little attention so far.

The lakes chloride content is low (0.009-0.035 meq/L) but higher than that of the rainwater samples (0.0019-0.0095 meq/L). In all the lakes, the 36Cl/Cl ratio (1*10-12 to 3*10-12 at/at) is higher by at least one order of magnitude than the natural atmospheric ratio (0.2*10-12 at/at) as determined previously from groundwater measurements in the lake Chad basin and in the Northern Saharan CT aquifer (Bouchez et al.2019, Hadj Ammar (2016)). These high ratios are a definite signature of the nuclear imprint, and thus of the lakes memory of atmospheric deposition, as already observed by our group in lake Chad, Iro and Fitri (Bouchez et al. 2019, Poulin (2019)). These data can then be used to determine the hydrological budget of the lake, independently of any water flux measurement, based on a simple one-box model assuming steady state for water and chloride. Indeed, simulating the transient response of the lake’s 36Cl to the bomb pulse allows us to estimate simultaneously the water residence time and the evaporation/precipitation ratio. Results from this model, as well as discussion of their comparison with classical hydrologic data will be shown at the meeting.

References:

Bouchez C. et al. 2019, (Paper in Scientific Report)

Hadj Ammar F. 2016 (Thesis)

Poulin C. 2019 (Thesis)
Flow and transport at the catchment scale: hillslopes vs river network who plays the leading role?
Authors: Fiori Aldo , Zarlenga Antonio , Cvetkovic Vladimir
Published: September 2022

Travel time distribution allows for an effective representation of all the physical processes occurring in hydrologic system and provides a stronger link between catchment-scale water flow and water quality models. The travel time distribution TTD has been extensively used in hydrological modeling and several approaches, with different level of complexity, have been developed in past.

The aim of our research is to investigate the travel time distribution in river catchments, specifically we would disentangle the relative contributions of the hillslopes and the river network in determining the TTD at the catchment outlet. Catchment is represented as a set of hillslopes connected to the river network; the effective recharge, moves first within the hillslopes and then is conveyed by the river network up to the outlet control section. Our theoretical framework combines a Boussinesq hillslope flow model with a GIUH-based formulation of transport along the river network. The TTD is characterized by the first two spatial moments of the travel times of the water particles crossing, at a given time, the catchment outlet section. Despite the assumptions required by the analytical development, the proposed approach is built on key physical processes and can be used to analyze the complexity governing the water age distributions and the travel time in catchments.

The analysis of a 10-year long series of synthetic recharge indicates that:

the travel time moments strongly depend on the hillslope flow dynamics, as a consequence transmissivity is a key parameter;

transport within river exerts a secondary effect;

the sequence of wet and dry periods, is also of primary importance in determining the travel time moments and their temporal fluctuations;

the variability of the travel times at the outlet, at a given time, is generally very large, with coefficient of variation typically larger than unity.

 
How drought affects flood risk: positive / negative effects and feedbacks in different cases
Authors: Van Loon Anne , Barendrecht Marlies , Weesie Ruben , Mendoza Heidi , Matanó Alessia , Koehler Johanna , Rohse Melanie , de Ruiter Marleen , Mazzoleni Maurizio , Ward Philip , Aerts Jeroen , di Baldassarre Giuliano , Day Rosie
Published: September 2022

Droughts are long-lasting and have a range of cascading impacts on society. These impacts and their responses can influence the further development of the drought itself, but also continue into the period after the drought ended. Especially if society is hit by a next hydrological extreme event, heavy rainfall resulting in flooding, the effects of this may be increased or decreased by the preceding drought and its impacts and responses. We here present a review and a global assessment of cases of these events, based on scientific literature, NGO and governmental reports, and newspaper articles, to study the diversity of how drought affects flood risk. We find that the balance between the positive and negative effects of extreme rainfall after a long dry period is mostly dependent on the underlying vulnerability and the effect of specific responses, and is different for different countries, and for different sectors and groups in society. Based on our initial analysis of the collection of case studies, we see some emerging patterns. For example, in Europe, the USA and Australia, the highly managed water system with hard infrastructure and early-warning systems makes that in most cases the rainfall after drought are managed and adverse effects mitigated, but also lock-ins exist that can make feedbacks of either inaction or maladaptation result in increased economic losses. In Africa and Latin-America, with a fragile governance system, less hard infrastructure, and a more exposed population, extreme rainfall after drought brings relief and replenishment of water resources, but also increased impacts, conflict and displacement. Here, we hypothesise that impacts are unequally distributed in society, because of issues of power, access to land and water resources, inadequate soft infrastructures, etc. We will test this hypothesis with an in-depth qualitative study of local stakeholder knowledge of these human-water processes in selected case studies. The typology of drought-to-flood events that we developed can serve as a starting point for further research on the complexity of these cascading events.
Groundwater modelling of a complex multilayer coastal aquifer under climate change in the framework of the DEM'EAUX ROUSSILLON project.
Authors: Lanini Sandra , Schorpp Ludovic , Dall'Alba Valentin , Renard Philippe , Dewandel Benoît , Ladouche Bernard , Bouchette Frédéric , Caballero Yvan
Published: September 2022

The Plio-Quaternary aquifer of the Roussillon plain (multilayer aquifer of more than 350 m thick, made up of sandy layers embedded in low-permeability clay material from the Pliocene and topped by alluvial formations from the Quaternary) was extensively studied in the framework of the Dem’Eaux Roussillon project. Relying on a conceptual model of the whole groundwater system describing the main factors controlling the hydraulic behaviour of groundwater flow (recharge areas, surface-groundwater interactions, sea water intrusion risk,…) of Quaternary and Pliocene aquifers, a numerical modelling exercise of both onshore and offshore reservoirs was performed.

Two parallel modelling approaches sharing a common description of the reservoir geometries, the boundary conditions and the pumping withdrawals locations were carried out, using two (not so) different modelling tools. Results comparison illustrates the uncertainty associated to numerical methods and calibration strategies applied for each modelling tool. Climate change projections were used to explore the future evolution of the groundwater resource and results of both modelling tools were compared. An analytical formulation of the increase of the hydraulic head of the sea due to swell and waves close to the coastline was provided. The analysis of its influence on the groundwater dynamics simulated by the models highlights the potential influence of storms and future sea level rise on the risk of saline intrusions for coastal sedimentary aquifers along the Mediterranean basin.
Detection of trends in observed river floods in Poland
Authors: Venegas Cordero Nelson , Kundzewicz Zbigniew , Jamro Shoaib , Piniewski Mikołaj
Published: September 2022

Poland is characterized by hydrometeorological variability, where conditions such as ice melt, snowmelt, extreme precipitation, and other factors might cause river floods. Climate change has had a direct influence on it, due to the shifts in parameters such as precipitation and temperature over the world. Therefore, evaluating the historical flood trends allow to establish a link between hydrology and water resource management.

The purpose of this study was to present trends in selected river flood indicators (magnitude, frequency, and timing) for a data set of 146 stream flow gauges, using the annual maximum daily flow and peak-over-threshold approaches. The gauges are also free from major human influences on flow regimes such as large dams. Two periods (1956-2019 and 1981-2019) were analyzed. The first one focused on a large temporal coverage (58 flow gauges), while the second one maximized spatial coverage (146 flow gauges). Trends were calculated using the non-parametric Mann-Kendall test (MK) and Sen slope for changes in magnitude and timing, while flood frequency trend was detected by chi-square test on parametric Poisson regression.

The flood trend detection in river flood indicators allowed us to identify areas with predominant decreases or increases. The northeast region of Poland showed a downward trend in flood magnitude with changes between -5 to -15% per decade using both methods, whereas the south part showed a predominantly upward trend.  The results are in general agreement with previous studies based on annual maximum flow. No evident trends were detected in flood frequency, where detected changes generally did not exceed ± 0.2 events per decade. An annual flood timing average on February-April was found in the northern and central parts of Poland, while May-June was the average in the southern-most basins. The flood timing showed a strong pattern of earlier flood occurrence in the southern half of the country, and an increasing trend (later flood occurrence) in the north-eastern and north-western parts, with changes of 4 and 8 days. The results showed the first analyses of a rather under-studied topic in Poland and leave an opportunity to study the attribution of changes in floods.
Improving runoff predictions by updating the subsurface state in the DDD model from observed runoff
Authors: Skaugen Thomas
Published: September 2022

A catchment is in a continuous state of recession although this can be difficult to observe due to added moisture from precipitation or snowmelt. For the updating procedure developed in this study, we need to use the runoff and the subsurface storage estimated for a state of pure recession. For an observed runoff value, the runoff caused by pure recession at the next timestep need to be estimated. This is obtained by the recession characteristic Lambda=log(Q(t)/Q(t+1)), which is estimated through an iteration procedure. Then, the subsurface storage for a state of pure recession can be estimated by assuming that the catchment behaves as a linear reservoir, with parameters specific for the moment of update. The rate constant of the linear reservoir is not all a constant but a function of the recession characteristic. The difference between observed runoff and runoff due to pure recession (distributed in time due to an UH estimated using the recession characteristic and the distance distribution describing the distances from points in the hillslopes to the river network) is the moisture needed to be added to the subsurface state of pure recession, giving us an estimate of subsurface state for the observed runoff. If the subsurface state in the model is different, then we need to add or subtract water to the model so that so the modelled subsurface state and the estimated subsurface state due to the observed runoff are equal. The model with the updated subsurface state has improved runoff predictions, and increased precision can be observed for several timesteps ahead. These are very preliminary, but promising results, and will, if successful, be of considerable value for the forecasting services.
Artificial intelligence for agricultural drought monitoring based on soil moisture and crop yield under change
Authors: Benso Marcos Roberto , Silva Roberto Fray , Gesualdo Gabriela Chiquito , Marques Patricia Angélica , Delbem Alexandre , Saraiva Antônio Mauro , Mendiondo Eduardo Mario
Published: September 2022

Water is a critical resource for food production. Climate change has shown that shifts in precipitation regimes and increases in atmospheric temperature threaten food production worldwide. Therefore, it plays an essential role as a driver in the water-environment-food nexus. Strategies to cope with impacts of climate risk require understanding the relationship between hydro-meteorological extremes and crop yield shortfalls to guide decision-making. The purpose of this paper is to propose a fully data-driven model for predicting the impacts of hydrological extremes on food production for decision-making at the municipal level. We use the Support Vector Machine (SVM) model considering a variety of kernels for predicting crop yields using reanalysis data of water storage (WS) from 0 to 28 cm of soil during the soybean growing season. We used ERA5 WS data for Paraná state in Brazil and official annual soybean crop yields (SBY) at the municipal level. We tuned a SVM radial basis function kernel with sigma and cost parameters for municipalities with significant production of soybean. The SVM model predicted crop yields accurately with R² ranging from 0.12 to 0.85. The use of soil moisture data increased model accuracy from 30 to 95% and reduced error from 5 to 58% in relation to using only SBY, except for one location. These results indicate that the model is better able to depict SBY during drier conditions, reducing prediction accuracy in years with average or above average yields. The model we proposed is useful for estimating crop losses due to water shortage at the municipal level. Our results suggest that using WS data from ERA5 as an additional input to past SBY adds relevant information for several applications such as risk transfer, irrigation planning and farm-level management with data that are made available for most countries. Our model has potential for climate impact studies coupled with projections from Global Circulation Models forced by Shared Socioeconomic Pathways (SPP).
Modelling rainfall event frequency through a temporal contagion model with external covariates
Authors: Treppiedi Dario , Sottile Gianluca , Adelfio Giada , Noto Leonardo Valerio
Published: September 2022

Physical modelling of atmospheric processes, such as rainfall events, is often difficult due to the complexity of the atmosphere and the large number of variables involved. At the same time, it is necessary to know, as carefully as possible, some characteristics of precipitation processes, such as rainfall magnitude and frequency, in order to better understand their impacts on the territory. For this reason, statistical frameworks able to use external covariates to explain the physical process could be a central point in research.

Starting from the rainfall events identified from continuous data series from about 40 rain gauges located in Sicily, this paper aims at assessing the occurrence of rainfall events in a fixed interval of time according to a temporal contagion model (branching process) with external covariates, within a regression-like framework (Adelfio and Chiodi, 2021).

In detail, we extend the model formulation proposed by Meyer et al. (2012) in the context of infectious disease transmission, suggesting the use of a specific branching-type model, born in seismic context (the ETAS model, (Ogata 1988, 1998)), in a regression-oriented version modelling. In the temporal ETAS model, the expected frequency of events in a time unit can be defined as the sum of a term that describes the long-term variation and a term that describes the short-term variation.

Accounting for further potential covariates in the model specification of the short-term variation component, may both explain some of the overall variability of the studied phenomenon (i.e., for decreasing the unpredictable variability) and provide a more realistic description of the observed activity. The Forward Likelihood for prediction (FLP) method (Chiodi and Adelfio 2011) is used for estimating the ETAS model components with the covariates.

In this application the mean rainfall intensity, the duration and the anomalies in temperature and relative humidity of the events have been considered as external covariates of the model in order to explain the events frequency. The first results of the model appear to be interesting, and special attention will be paid to the sample of convective precipitation events identified using the same dataset (Sottile et al. 2021).
Aiming for globally available but locally relevant seasonal drought risk forecasts with GLOFFIS
Authors: Sperna Weiland Frederiek , Trambauer Patricia , Hendriks Dimmie , den Toom Matthijs , Weerts Albrecht , Verkade Jan
Published: September 2022

An increasing number of countries and river basins worldwide are confronted with droughts. Inevitably, this leads to an increasing pressure on the available water resources and associated drought risks. In order to prevent severe drought impacts, such as food insecurity and possibly even conflicts on water use, timely and focused drought mitigation measures need to be taken. Here, early stage drought forecasts can be of great value, especially when they include local sector-specific information.

Over the past years Deltares developed the Global Flood Forecasting and Information System (GLOFFIS). Up until recent its focus was on floods but now seasonal forecasts have been included to provide drought early warning information. GLOFFIS is based on the wflow framework for hydrological modelling which is embedded within the Delft-FEWS forecast production system that is applied in many countries worldwide.

Wflow relies on so-called pedo-transfer functions that translate input base maps such as land use and soil type to estimate model parameter values. Herewith the model requires little calibration and can easily be implemented for additional basins. The set-up of GLOFFIS is global, yet for the drought forecasting component it was decided to include only high-resolution basin scale models since many global initiatives already exist and the resolution of global models generally lacks granularity to inform decision making. The system is flexible and contains workflows to be easily extended with hydrological models for new basins on demand. The drought forecasts are informed by means of standard drought indicators like discharge anomalies, soil moisture deficit, evaporation deficit indices. This list can be extended depending on the local need. So far hydrological models have been included for the Paraná, Lempa, Rhine and Niger river basins. The application for the Parana will be demonstrated as this basin in South-America currently experiences a severe drought.