Heterogeneous Water Research Articles

Effects of clonal integration on photochemical activity and growth performance of stoloniferous herb Centella asiatica suffering from heterogeneous water availability

Clonal integration allows translocation of water between interconnected ramets, improving fitness of clonal plants growing in heterogeneous water availability. However, few studies have been conducted to investigate the effects of clonal integration on physiological responses of clonal plants suffering from heterogeneous water availability. A greenhouse experiment was conducted by using clonal fragments of the stoloniferous herb Centella asiatica with two successive ramets. The basal ramets were grown in patches with 40% soil moisture (high water availability), while the apical ramets were grown in patches with 40% (high water availability), 20% (medium water availability) and 10% soil moisture (low water availability) respectively. Stolons between the basal and apical ramets were severed (clonal integration impeded) or retained intact (clonal integration allowed). Our results showed that clonal integration relieved negative impact of water deficiency on the apical ramets in terms of photochemical activity and growth performance. Clonal integration modified biomass partitioning both for the apical ramets growing in low water availability and the basal ramets growing in high water availability. In addition, significant cost of clonal integration was observed in terms of growth performance of whole clonal fragments. A possible explanation is that increased biomass allocation to root may reduce capturing of light energy, producing negative effect on biomass accumulation of the basal ramets under high water availability contrast between patches. The results suggest that the net benefit of clonal integration may depend on the contrast of resource availability between interconnected ramets.

Warming-up and evaporation characteristics of homogeneous and heterogeneous water droplets

The study reports the experimental results of warming-up and evaporation of homogeneous and heterogeneous water droplets at high temperatures, 100–600 °C. The heterogeneous water droplet is formed by covering a solid opaque graphite particle by a thin water layer. Differences between the warming-up mechanisms of the homogeneous and heterogeneous water droplets with an initial liquid volume from 10 μl to 20 μl at the convective heating are shown. The contactless method Planar Laser-Induced Fluorescence allows the analysis of the temperature distributions inside the homogeneous droplets and inside a liquid phase of the heterogeneous droplets, laying emphasis on the novelty of the research. A maximum temperature in the central part of the liquid phase of the heterogeneous droplets is approx. 90 °C; a maximum temperature in the homogeneous droplets is approx. 50 °C. The heterogeneous droplet heats up by 20 ± 3% longer than the homogeneous one. Moreover, a warming-up rate of the liquid phase of the heterogeneous droplet is less than that of the homogeneous water droplet by 85%. However, the size decreasing rate of the heterogeneous droplets is sometimes higher than that of the homogeneous droplets by 80%. The mean and instant evaporation rate of homogeneous and heterogeneous water droplets are compared. The study discusses an influence of convection in the liquid phase of the heterogeneous droplets on evaporation characteristics. The time of the complete water evaporation decreases by 40% due to a solid inclusion presence. A dimensionless criterion of the convective heat transfer enhancement in a water droplet containing the solid opaque inclusion is used to generalize the experimental data. The findings obtained are critically important to improve the existing high-temperature technologies and methods of water purification and to develop innovative ones.

Can Ni Complexes Behave as Molecular Water Oxidation Catalysts?

The present report uncovers the borderline between homogeneous and heterogeneous water oxidation catalysis using a family of Ni complexes containing oxamidate anionic type of ligands. In particular...

Multigroup Cross-Section Generation with the OpenMC Monte Carlo Particle Transport Code

High-fidelity deterministic transport codes require highly accurate multigroup cross sections (MGXS). Monte Carlo is increasingly cited as a reactor-agnostic approach to MGXS generation since it is unconstrained by the engineering-based approximations that limit the applicability of deterministic MGXS generation tools. This paper introduces a new framework that uses the OpenMC Monte Carlo code to generate MGXS for use in multigroup transport codes. The openmc.mgxs module is built atop OpenMC’s Python application programming interface to process tally data output by the OpenMC executable. This paper validates the module to generate MGXS that enable the multigroup OpenMOC transport code to compute eigenvalues to within 50 pcm and fission rates to within 1% of reference solutions for two heterogeneous pressurized water reactor benchmarks.

Main performance analysis of kitchen waste gasification in a small-power horizontal plasma jet reactor

Plasma gasification technology has been demonstrated in recent studies as one of the most effective and environmentally friendly methods for solid waste treatment, which could be attractive for resource and energy recovery from kitchen waste. This study focuses on the effects of plasma gasification of kitchen waste replaced by 85% flour and 15% vegetables (Mass Fraction), including dimensionless operation parameters, ER (equivalence ratio), SFR (steam to feedstock ratio) and the gasification efficiency. The Horizontal plasma jet reactor is employed in the experiments. It is found that the influence of the equivalence ratio on syngas can be divided into positive and negative parts. And the steam injection is conducive to improving the yield of syngas, which mainly results from the heterogeneous water gas shift reaction. The optimal experimental parameters can be obtained at ER = 0.095 and SFR = 0.084. Besides, the maximum first and second efficiency of plasma gasification during these cases occurs in SFB = 0.084, accounting for 28.2% and 23.0%, respectively, which needs to study further to get improvement. The XRD and Raman spectra are applied to characterize the residual char, which may illustrate that the degree of graphitization is competing with a high yield of syngas during plasma gasification.

Quantification of Leaf Growth, Height Increase, and Compensatory Root Water Uptake of Sunflower in Heterogeneous Saline Soils

Core Ideas Compensatory growth and root water uptake are observed in heterogeneous saline soils. Three types of indexes are proposed to determine the heterogeneous water and salt stresses. Critical compensation factors for each growth stages of sunflower are determined and linked with heterogeneous soil water and salt. ABSTRACTTo characterize the crop growth and root water uptake (RWU) under heterogeneous soil water and salt (SWS) conditions, 2‐yr subplot experiments with sunflower (Helianthus annuus L.) were conducted at the Yichang experimental station in the Hetao Irrigation District (HID), China. Three types of stress indices, including average (αmean, ω), positional (αupper, αdeeper), and extreme (αsmax, αsmin) indices, were defined to quantify the heterogeneity of the SWS stresses at each growth stage of sunflower. The relative increase in the leaf area index (REDLAI) and height (REDH) of sunflower were quantified based on correlation analyses with SWS heterogeneity indices. The critical compensation factor (ωc) of RWU at different sunflower growth stages was inversely calculated based on the Feddes Jarvis (FJ) model and quantified using a defined soil environmental stress factor (δ). The results showed that the vertical heterogeneity of SWS gradually improved and that soil stress indices varied with sunflower growth. The relatively high correlations of REDLAI and REDH with the ω (average stress coefficient weighted by the root length density) were determined, and quantitative relationships of the REDLAI and REDH with the ω at different growth stages were established. Furthermore, relatively high coefficient of determination (R2) values of quantitative relationships between ωc and δ were acquired (0.75, 0.78, 0.64, and 0.46 at the seedling, budding, flowering, and maturity stages, respectively). The proposed methods could improve the prediction of crop leaf growth, height development, and compensatory root water uptake (CRWU) based on SWS information in salt‐affected regions.

Correlating soil and urban planning for sustainable water cycle

Abstract Hydrological modelling and processes using modern hydrological models like SCS Curve Number, HCS, HSPF (Hydrologic Simulation Package-Fortran) and kinematic wave models are widely used nowadays in various researches. But using these modelling in drawing the attention of urban planners for challenges and multiple interactions in heterogeneous urban catchments and water systems is still a shortcoming in water sensitive, planning principle. The art of urban planning and technical implementation using behavioural changes in water responses to urban catchments is the need of present urban planning. The complexities of effects and behavioural changes in the water system or urban catchments and incomplete knowledge of these interactions result in failures of sustainable urban developments. Urban planning needs water sensitive methodology to synchronize soil, water and land cover operational with the population over it. The paper reviews the water sensitive urban planning considering the role of soil in urban planning for water and lands correlations, with the purpose of identifying current limitations and opportunities for future urban planning. Data availability and simplified methods are still a strong limitation for urban planners. Therefore, urban hydrology is often simplified either as a study of surface runoff over impervious surfaces or hydraulics of piped systems. Hence the paper provides approach and universal solution to forecast the behaviour of urban catchment for urbanization in terms of natural land-water cycles and its application in planning existing or new urban catchments. The methodology consists of observing Urban watershed catchment areas with different soil groups and built-up induction over them. A detailed study of water levels in hydrological wells and runoff pattern for the period of 40 years have provided a linear correlation of soil, roughness, land cover, infiltration, ground water and built upon the basis of soil behaviours. These correlations conclude to make regression equations as the blueprint for future urban planning norms to be followed by the planners, engineers, and hydrologists for planning.

Mathematical Modeling of High-Temperature Vaporization of Heterogeneous Water Drops

Experimental data on high-temperature vaporization of heterogeneous water drops, obtained by high-speed video recording, and Ansys Fluent software package were used to develop a predictive mathematical model of heat and mass transfer. An assessment was made of the influence of the key process parameter, namely, the temperature of a gaseous medium ( Tg = 500 – 850 K), on the integral characteristics of vaporization of homogeneous drops of water and drops of aqueous suspension containing graphite inclusions. The dependencies of complete vaporization and disintegration (due to ebullition) time on the temperature of the gases are established. The numerical modeling and experimental data are compared.

Magnetic sedimentation of nonmagnetic TiO2 nanoparticles in water by heteroaggregation with Fe-based nanoparticles

A new approach to remove TiO2 nanoparticles from water is studied. Composite Fe3O4-SiO2 and Fe-C-SO3H nanoparticles with magnetic cores (5 nm) were designed to be used as flocculants for magnetic sedimentation of nonmagnetic TiO2 nanoparticles in water. The sedimentation dynamics of heterogeneous water suspensions (starting solid phase concentration of 100 mg/l) of (TiO2)1−x(Fe3O4-SiO2)x (x = 0.15–0.55) and (TiO2)1−x(Fe-C-SO3H)x (x = 0.01–0.17) was studied in a gradient magnetic field (B = 0.3 T, dB/dz < 0.16 T/m) for pH = 3–6. The NMR relaxometry and the UV - spectrophotometric methods were used to monitor the residual concentration of Fe3O4-SiO2, Fe-C-SO3H and TiO2 nanoparticles in water after magnetic sedimentation. The hydrodynamic sizes of the heteroaggregates (dh) depend on the pH value and on the mass content of the magnetic component, x. For the mixed (TiO2)1−x(Fe3O4-SiO2)x water suspensions the maximum of dh = 5 μm and the fastest sedimentation are reached for x = 0.35–0.5 at pH = 3, 4, and for x = 0.2 at pH = 5. At this regime, the highest efficiency of TiO2 particles removal from water, that is, 99.7% for 30 min, was observed. For the mixed (TiO2)1−x(Fe-C-SO3H)x water suspensions the largest heteroaggregates and the fastest sedimentation were observed for the smaller mass content of the magnetic flocculant, x = 0.03–0.05 at pH = 3, 4 and for x = 0.03 at pH = 5. However, by adding Fe-C-SO3H nanoparticles flocculant the achieved minimum residual concentration of TiO2 nanoparticles in water is two orders of magnitude higher. These results are discussed by assuming a specific distribution of Fe - based nanoparticles by heteroaggregation with TiO2 nanoparticles.

Synergy of carbocatalytic and heat activation of persulfate for evolution of reactive radicals toward metal-free oxidation

Abstract Persulfate (or peroxydisulfate, PDS) is one of green and low-cost sources of sulfate radicals (SO4 −) in advanced oxidation processes (AOPs) for in situ remediation of contaminated soil and water. The key in AOPs is to develop an effective technique for PDS activation. In this paper, nitrogen-doped single-walled carbon nanotubes (N-SWCNTs) were employed as a metal-free catalyst to activate PDS for oxidation of a diversity of organic contaminants such as nitrobenzene (NB), phenol, benzoquinone and sulfachlorpyridazine. For the first time, the coupling effects of carbocatalysis and heat were investigated in a range of 5–75 °C on PDS activation, which indicated that organic oxidation efficiency was enhanced at elevated temperatures. The presence of the carbocatalyst impressively decreased the PDS activation energy from 53.4 (by heat) to 10.3–22.5 kJ/mol (heat/carbocatalysis). Intriguingly, the mechanisms of heat-assisted carbocatalysis were temperature-dependant and the synergy of the heat/carbon integrated system appeared to be phenomenal at a high temperature region (55–75 °C). The thermal stimulation promoted PDS to generate hydroxyl radicals via heterogeneous water oxidation and mutual transformation from sulfate radicals, evidenced by the selective radical quenching and spin trapping techniques. The carbocatalyst boosted the radical production by simultaneously activating the reactants (PDS and organics) with the N-doped carbon atoms and facilitating the electron transport as a conductive substrate. Therefore, this study advances the understanding in the effect of reaction temperature on persulfate activation and unveils the synergy of carbocatalysis with heat for enhanced PDS activation.

Conjugated Carbon Nitride as an Emerging Luminescent Material: Quantum Dots, Thin Films and Their Applications in Imaging, Sensing, Optoelectronic Devices and Photoelectrochemistry

AbstractOver the past few years, graphitic/polymeric carbon nitride (CN) has attracted widespread attention due to its interesting electronic properties, which have been exploited in various applications, including, for example, in photo‐ and electrocatalysis, heterogeneous catalysis, CO2 reduction and water splitting. Its unique and tunable optical, chemical, and catalytic properties, alongside its low price and remarkably high stability to oxidation and harsh chemical environments, make it a very attractive material for optoelectronic devices as well as imaging and sensing‐related applications. In this Minireview, we will focus on the optical and photophysical properties of CN films and quantum dots and their potential applications in sensors, LEDs, solar cells and other photoelectronic devices. The synthetic approaches which determine the final chemical and photophysical properties of the CN materials are thoroughly elaborated.

Spatial and temporal variation in otolith chemistry and its relationship with water chemistry: Stock discrimination of Sperata aor

AbstractLong‐whiskered catfish, Sperata aor (Hamilton 1822), is commercially important in food, ornamental and sport fisheries. The fish is mainly caught from the wild populations because its aquaculture practices are not commercialised. Inland fishery in the Ganga basin is mostly unorganised; hence, no published report is available on the trend of S. aor production from the selected habitat. In India, S. aor has been categorised vulnerable mainly due to natural and anthropogenic threats. Otolith chemistry shows variation with changing physico‐chemical conditions of the fish habitat. Therefore, the present study was conducted with the objective to analyse spatio‐temporal variations in water chemistry in relation to environmental factors; relationship between water and otolith chemistry; and spatio‐temporal variations in otolith chemistry to discriminate the stocks of S. aor inhabiting the River Ganga. Most of the element: Ca ratios in water samples did not show significant correlations with environmental factors, viz. temperature and conductivity. Only few element: Ca concentrations in otoliths were positively correlated to their corresponding ratios in the ambient water. In the selected study area, the S. aor populations were discriminated into four stocks possibly because of heterogeneous water chemistry at the sampling sites, and physical barriers. In the present study, otolith chemistry showed relatively low temporal variability as compared to spatial variability; thus, the classification accuracy of individuals to their original populations remained consistent over the selected time period. The findings could be useful in devising scientifically sound management strategies and/or any conservation plans for the vulnerable S. aor populations inhabiting the River Ganga.

Throughfall and stemflow heterogeneity under the maize canopy and its effect on soil water distribution at the row scale

Quantitative knowledge of the spatial variability of soil infiltration processes caused by canopy rainfall redistribution has significant hydro-chemical consequences owing to their influence on nutrients leaching and groundwater recharge in agricultural ecosystems. The heterogeneity of throughfall and stemflow under the maize canopy was quantified in this study, and its subsequent effect on soil water distribution at the row scale was further examined. Throughfall at 15 locations within and between maize rows as well as stemflow was observed over three growing seasons of 2015, 2016 and 2017 on the Loess Plateau of China. Soil water content at five depths in the row and interrow positions were continuously monitored. The results showed that throughfall was significantly different among the five sampling sections between maize rows, with the highest throughfall in the center and a decreasing trend towards the maize row. Greater throughfall was observed on the windward side of the maize row than on the leeward side. These spatial patterns persisted for most rainfall events. However, much higher net rainfall (throughfall plus stemflow) was obtained in the row positions when stemflow was further considered. Net rainfall reaching the row positions resulted not only in earlier water infiltration, but also in deeper penetration. The results suggested that the presence of maize canopy altered the soil surface water flux and thus caused heterogeneous infiltration water in the soil, which has implications for guiding the placing of fertilizers/pesticides and soil erosion management in the maize field.

Influence of solid nontransparent inclusion shape on the breakup time of heterogeneous water drops

The heat and mass transfer of evaporating heterogeneous water drops was numerically studied to determine the effects of internal solid non-transparent inclusions with different shapes on evaporation characteristics under intensive heating. Explosive breakup times of heterogeneous water drops were determined for various temperature of the gaseous environment with different solid inclusion shapes. Predicted results show that at 550 K, the minimum fragmentation time (~5.5 s) corresponded to the water drops with spherical inclusion as well as the maximum one (~9 s) was the water drops with ellipsoidal inclusion. At higher temperature (850 K), the minimum fragmentation time (~1.5 s) corresponded to the water drops with ellipsoid inclusion while the maximum time was for the water drops with sphere inclusion. Research results could be used for the development such technologies as fire extinguishing, surface treatment by heterogeneous flows, defrosting of granular media by high-temperature gas-vapor-drop flows, and thermal and flame water purification.

Heterogeneous photocatalytic water reduction using a QD-cluster pentacobalt polyoxotungstate complex

Efficient, robust, and heterogeneous WRC QD-cluster Cs12[Co3W(H2O)2(CoW9O34)2]·46H2O, as a unique alternative of homogeneous WRCs by incident visible light.

Measurements and simulation of leaf xylem water potential and root water uptake in heterogeneous soil water contents

The relationship between leaf water potential, transpiration rate and soil water potential is complex, particularly when the soil water potential in the root zone is not uniform, which is the rule rather than the exception in soils. Our objectives were: 1) to measure the effect of heterogeneous soil water potentials on the relation between leaf water potential and transpiration rate and 2) to test whether root water uptake models could predict this relation. To this end, we combined the root pressure chamber technique, which allows measuring the suction in the leaves of transpiring plants, with two models of root water uptake, a simple one where soil and roots are presented as resistances in series and a more detailed 3D root architecture model. The experiments were carried out with lupines grown in sandy soil, for which the root architecture and root hydraulic properties had been previously estimated. The soil was partitioned in two layers separated by a coarse sand layer that allowed the roots to grow through but limited the water redistribution between the layers. Three scenarios (wet-wet, dry-wet, dry-dry) were tested. The results showed that the relation between transpiration and leaf water potential was linear in all scenarios. As the upper soil layer severely dried, the conductance of the soil-plant system decreased by ca. 1.65 times compared to the conductance of the plant-soil system in a uniform wet soil. As both layers dried, the conductivity was 8.26 times lower compared to the uniform-wet case. The combination of the experiment and modelling showed that a simple model is capable to reproduce the relation between transpiration, leaf water potential and soil water potential (despite an offset in the leaf water potential). Both simplified and the 3D root architecture models were capable of reproducing the measured changes in hydraulic conductance of the plant-soil system due to the soil drying. However, both models overestimated the measured leaf water potential by 0.1 MPa, probably because of a gradient in osmotic potential between the xylem and the soil. The simulations predicted the occurrence of hydraulic lift, even at day time conditions, although the hydraulic lift was relatively more important at low transpiration rates. The simulation suggested that a root architecture model is needed to estimate the variations of water uptake along the individual roots and this might be crucial to properly model hydraulic lift.

Novel cobalt-fumarate framework as a robust and efficient electrocatalyst for water oxidation at neutral pH

The development of efficient and cost-effective electrocatalysts for oxygen evolution reaction is a priority research area. Metal-organic frameworks (MOFs) have recently captured attention as heterogeneous water oxidation catalysts. In spite of their robustness and stability under specific pH conditions, the relatively low current density achieved is their main drawback. Herein, we explored a cobalt based framework [Co(bpy)(fa)]n(DMF)0.25(bpy)0.25 (1) {bpy = 4,4ʹ-bipyridine, fa = fumarate, DMF = dimethylformamide} as an efficient electrocatalyst for the water oxidation reaction. Compound 1 exhibits excellent activity in a neutral phosphate buffer solution. Chronoamperometric studies show that 1 offers a current density of 10 mA cm−2 at only η = 382 mV. Onset over-potential of 248 mV is observed which holds a Tafel slope value of 84 mV dec−1. The catalyst showed a turnover frequency (TOF) of 2 × 10−3 s−1 for oxygen evolution reaction (OER) at 289 mV. Detailed electrochemical studies, including long-term electrolysis, indicates the potential of compound 1 to be utilized as heterogeneous catalyst toward the oxygen evolution reaction.

Removal of Very Small Submicrometric Particles by Water Nucleation: Effects of Chemical–Physical Properties of Particles

The control of particle emissions from industrial plants is a crucial point in pollution control mainly because the commonly used abatement devices are inefficient in the dimensional range between 0.1 and 1 μm. An innovative technique to control particle emissions exploits the water vapor condensation onto submicrometric particles acting as condensation nuclei. In this way, particle sizes increase from nanometric up to micrometric scale. The aim of this work is to analyze the 150 nm particle growth process, activated via a heterogeneous water condensation mechanism, as a function of the vapor concentration. Particle chemical–physical features are also taken into account. The evolution of the particle growth process has been followed at a lab scale along the axis of a laminar flow chamber by means of a spatially resolved measurement of the polarization ratio of the condensation nuclei and growing droplets. The main result reported here is the scheme of interpretation of the temporal profile of the polarization ratio related to the composite particle (particle embedded in the water layer) growth. The controlling mechanism of the overall condensation process has been identified with respect to the saturation conditions, evaluated on the basis of different theories available in the literature. The covering process has been found to be active also under conditions far from saturation of the vapor bulk phase. Moreover, it has been clearly shown that, irrespective of the particle nature, the nucleation activation and droplet growth occur almost simultaneously on all particles present in the control volume, with a capture efficiency close to unity. The water nucleation activation time also depends upon the particle chemical–physical characteristics. This paper also demonstrates that the experimentally determined characteristic times of nucleation and growth of the liquid layer are compatible with residence times of an industrial unity and can be used to condition its design.

Bioenergetic consequences of warming rivers to adult Atlantic salmon Salmo salar during their spawning migration

Abstract Climate change poses a challenge to wild fishes, yet little is known about the behavioural use and metabolic consequences of thermally heterogeneous water encountered by wild salmon during their energetically demanding upstream spawning migration. Temperature, body size and activity levels were modelled to predict energy depletion of salmon during their spawning migration in rivers. Archival temperature loggers revealed the thermal habitat of adult migrating Atlantic salmon (Salmo salar Salmonidae), which we used to apply bioenergetics models that estimated size‐dependent temperature‐driven metabolic expenditures as part of the costs of the migration. Between July 16 and August 19, the mean water temperature experienced by salmon (tFISH) ranged from 11.5 to 18.0°C (14.5 ± 1.2 SD °C) and closely followed the ambient surface water temperature (tRIVER) of the river (11.5–18.5°C; 14.8 ± 1.4°C) such that the regression equation tFISH = 3.24 + 0.76 (tRIVER) was highly correlated with observations (R2 = 0.94). Although temperature increases were predicted and confirmed to increase energetic costs, rates of energy depletion were more sensitive to changes in swimming speed and body size than to temperature increases in the range explored for this system. We conclude that warming could contribute to changing life history phenotypes of salmon in some rivers, for example, delayed river entry or reduced probability of iteroparity, with potentially more dire consequences for smaller individuals.

Understanding terrestrial water storage variations in northern latitudes across scales

Abstract. The GRACE satellites provide signals of total terrestrial water storage (TWS) variations over large spatial domains at seasonal to inter-annual timescales. While the GRACE data have been extensively and successfully used to assess spatio-temporal changes in TWS, little effort has been made to quantify the relative contributions of snowpacks, soil moisture, and other components to the integrated TWS signal across northern latitudes, which is essential to gain a better insight into the underlying hydrological processes. Therefore, this study aims to assess which storage component dominates the spatio-temporal patterns of TWS variations in the humid regions of northern mid- to high latitudes. To do so, we constrained a rather parsimonious hydrological model with multiple state-of-the-art Earth observation products including GRACE TWS anomalies, estimates of snow water equivalent, evapotranspiration fluxes, and gridded runoff estimates. The optimized model demonstrates good agreement with observed hydrological spatio-temporal patterns and was used to assess the relative contributions of solid (snowpack) versus liquid (soil moisture, retained water) storage components to total TWS variations. In particular, we analysed whether the same storage component dominates TWS variations at seasonal and inter-annual temporal scales, and whether the dominating component is consistent across small to large spatial scales. Consistent with previous studies, we show that snow dynamics control seasonal TWS variations across all spatial scales in the northern mid- to high latitudes. In contrast, we find that inter-annual variations of TWS are dominated by liquid water storages at all spatial scales. The relative contribution of snow to inter-annual TWS variations, though, increases when the spatial domain over which the storages are averaged becomes larger. This is due to a stronger spatial coherence of snow dynamics that are mainly driven by temperature, as opposed to spatially more heterogeneous liquid water anomalies, that cancel out when averaged over a larger spatial domain. The findings first highlight the effectiveness of our model–data fusion approach that jointly interprets multiple Earth observation data streams with a simple model. Secondly, they reveal that the determinants of TWS variations in snow-affected northern latitudes are scale-dependent. In particular, they seem to be not merely driven by snow variability, but rather are determined by liquid water storages on inter-annual timescales. We conclude that inferred driving mechanisms of TWS cannot simply be transferred from one scale to another, which is of particular relevance for understanding the short- and long-term variability of water resources.