Variations In Water Content Research Articles

Physiological characteristics of IRR 400 series rubber clones (Hevea brasiliensis Muell. Arg.) under drought stress

Background: Drought stress is one of the main causes of plant death. Strategies for plant survival include triggering of specific signaling pathways and tolerance mechanisms. Rubber plantations have many uses, including in forest revitalization and as foreign exchange sources, job sources, and as an alternative source for building materials and furniture. The rubber plant’s response to drought stress is a complex biological process. Planting tolerant rubber clone in drought prone areas would be more appropriate. The present study is aimed to identify drought tolerant traits in order to select drought-tolerant clones at juvenile stage itself. Methods: The first factor examined for this research was the clones (IRR 425, IRR 428, IRR 429, IRR 434, IRR 440, RRIC 100, and BPM 24), with water content (30%, 60%, and 90%) as the second factor studied. The study was arranged on a factorial randomized block design and repeated three times. Characteristics observed included total sugar (µM), proline (mg/L), chlorophyll a, b, total (µg/mL), hydrogen peroxidase (µmol/g), ascorbate peroxidase (unit/mg), superoxide dismutase (unit/mg), and peroxide dismutase (unit/mg). Results: The tolerance ability of the IRR 400 series rubber clones to drought stress was determined by observing the concentrations of total sugar and proline, which were higher when the plant was treated with a lower water content. The selected clones tolerant to drought stress were RR 425 and IR 434 with high total sugar and proline. Other characteristics, namely chlorophyll a, b, and total, as well as hydrogen peroxidase, ascorbate peroxidase, superoxide dismutase, and peroxide dismutase, cannot be used as selection characteristics for this study. Conclusions: This drought study of IRR 400 clones with varying water content percentages illustrated that the total sugar and proline characteristics could be used to distinguish tolerance levels.

Mapping depth-integrated microphytobenthic biomass on an estuarine tidal flat using Sentinel satellite data

Microphytobenthos (MPB) are central to benthic tidal flat ecological networks. Large-scale information on total MPB biomass is difficult to obtain from traditional in-situ measurements. Here, we assessed the effectiveness of using surface sediment properties as proxies for predicting the total (depth-integrated) MPB biomass with Sentinel satellite data. First, the best subset regression was applied to the in-situ data to determine the properties that best predict the biomass decay rate with depth (sampling every cm up to 10 cm depth). Then, data from a controlled laboratory experiment were used to analyse the spectral response to different sediment properties (i.e., variations in sediment grain size, organic matter and water content). Subsequently, an algorithm was developed to obtain the spatial distribution of the sediment properties and the depth-integrated total MPB biomass from remote sensing data. Finally, we presented a case study in which the seasonal dynamics of total (depth-integrated) MPB biomass were obtained from Sentinel-2 Multispectral Instrument (MSI) satellite data using the Google Earth Engine (GEE) platform. The results showed that (1) the vertical distribution of MPB biomass on a tidal flat could be predicted by the surface MPB biomass, median grain-size (D50) and water content (W0) of the sediment (top 1 cm); (2) the near infrared (NIR) band absorption depth was a key feature in estimating D50 and W0; and (3) the seasonal variation in the total (depth-integrated) MPB biomass was prominent in Chongming Dongtan, Changjiang Estuary. We concluded that the depth-integrated exponential decay algorithm was useful for estimating total MPB biomass and, combined with mappable sediment-surface data, could help map the total MPB biomass in estuarine tidal flats at a large scale.

Variation and prediction of unfrozen water content in different soils at extremely low temperature conditions

The unfrozen water content in frozen soil is the critical factor for liquid water migration, frost heaving and thawing settlement during freeze–thaw process, and its content largely depends on soil texture and temperature. Herein, the unfrozen water content in different soils was measured by low-field nuclear magnetic resonance (NMR) at extremely low temperature ranging from −80 to 0 °C. The effect of soil properties on the variation of pore water in soil during freezing is analysed by combining T2 relaxation curve and freezing characteristic curve. The results indicate that soil properties affect the phase transition process between liquid water and solid ice in frozen soil, and the pore size distribution plays a leading role in capillary water freezing in the severe phase transformation zone. When unfrozen water develops from the transitional phase transformation zone to the frozen stability zone, the freezing of adsorbed water in soil is affected by clay content. In addition, by analogy with the soil freezing characteristic curve, a prediction model of unfrozen water content of soil is established in accordance with the phase transition process of liquid water, and the accuracy of the model is further confirmed by comparing the test results. Sensitivity analysis of the proposed model parameters revealed that the parameters are closely related to the pore size distribution and the clay content. The proposed model expands the response range between the variation of unfrozen water and temperature by experimental means, and realizes the prediction of unfrozen water content in different types of soil at extremely low temperature. This study would provide significant reference for exploring the heat-moisture migration and mechanical strength in frozen soil.

Effect of conditioning schemes on mechanical properties of EPB shield soil

Shearing conditioned sands under different pressure conditions requires understanding their mechanical properties with various conditioning schemes to ensure feasible conditioning during earth pressure balance (EPB) shield tunnelling in sandy strata. This paper investigates the effect of bentonite slurry and foam, conditioned with sodium carboxymethyl cellulose (Na-CMC), on the workability of sand with varying water content, to obtain preliminary conditioning schemes. The conditioned sands with suitable workability are tested using a pressurized vane shear apparatus to obtain their mechanical properties, including compressibility, resilience, and shear strength before and after resiling. Results indicate that Na-CMC can reduce filtration loss of bentonite slurry and foam expansion ratio (FER) of foam, whereas enhance the stability of them. The foam injection ratio (FIR) of foam-conditioned sands and the maximum slurry addition of slurry-foam-conditioned sands decrease linearly with increasing the initial water content of sand, provided the conditioned sands have suitable workability. Increasing the FIR can remarkably increase the void ratio of conditioned sands, which maintains high compressibility and resilience, and low shear strength before and after resiling. The addition of bentonite improves the workability of sand. The conditioning schemes are feasible when the total stress is lower than a specific critical value. The critical total stress can be increased by increasing FIR and reducing the water content of sand or slurry-conditioned sands. This paper provides critical guidance for the design of conditioning schemes.

Fabrication of TiO2 nanotubes with effect of water and in‐situ condition for biomedical application

AbstractSynthesis of TiO2 nanotubes on titanium alloys for environmental and energy applications are highly encouraged by medical industries. Formation of nanotubes on titanium material delivers superior properties in the view of phase transformation, surface morphological, nanomechanical properties, and corrosion resistances. In this research work, synthesis of TiO2 nanotubes under 8 and 12 Vol. % of water content with in‐situ voltage condition. The fabricated nanotubes surface morphology was analyzed with the use of HR‐Sem. The formation of nanotubes surface has been identified with composite faces of smooth and rough (length of 1.6 and 1.8 μm) by the effect of water content and voltage variations. The nanomechanical properties were analyzed with nanoindentation Pmax received as max of 265 and min of 248 μN. Nanotubes strength depends on the nanotubes length. Potentiodynamic polarization analysis indicated that combination of smooth and rough surfaces was highly encouraging the corrosion resistances.

Determination of nuclear magnetic resonance T2 cutoff in remoulded loess by the freezing point

AbstractProton nuclear magnetic resonance (NMR) is widely applied to characterize the microscopic properties of hydrogen‐containing porous media. The transverse relaxation time cutoff (T2c) value is the crucial parameter for the quantitative analysis of NMR data. Currently, there is no universal method for the determination of the T2c in clayey soils. This study aimed to develop a laboratory method for determining the T2c of remoulded loess by the freezing point of loosely bound water. Malan loess, a kind of typical clayey silt, was used as test material. Based on the soil freezing characteristic, NMR measurements were performed on remoulded loess with different macro‐parameter controls during the cooling process to obtain the T2 spectrum at each target temperature. By analysing the variation of unfrozen water content with temperature reduction, the freezing point of loosely bound water and the T2c value within the freezing‐point range was determined. The freezing point of loosely bound water in remoulded loess is about −3 to −5°C and that of firmly bound water is less than −5°C. Accordingly, the T2c value of remoulded loess is determined to be 1.5–1.8 ms. The assessment of heating and cooling process and different methods for determining the T2c shows that the laboratory method by the freezing point is effective and reliable, and the T2c determined by statistical methods is worthy of further study and improvement. The saturated permeability of remoulded loess is evaluated according to the determined T2c, and two NMR‐based permeability equations can well reflect pore water distribution in remoulded loess, but to a certain extent, both equations ignore soil microstructure, pore connectivity and chemical effects of pore solution. The laboratory method by the freezing point and the determined T2c value of remoulded loess fill the gap of NMR measurement in loess analysis and are of great significance for low‐plastic clays and clay types.

Decline in stability of forest productivity in the tropics as determined by canopy water content

The impacts of low soil moisture (SM) and high vapour pressure deficit (VPD) on tree's photosynthesis and productivity are ultimately realized by changing water content in the canopy leaves. In this study, variations in canopy water content (CWC) that can be detected from microwave remotely sensed vegetation optical depth (VOD) have been proposed as a promising measure of vegetation water status, and we first reported that the regulation of CWC on productivity stability is universally applicable for global forests. Results of structural equation model (SEM) also confirmed the significant negative effect of CWC on coefficient of variation (CV) of productivity, indicating that the decrease in CWC could inevitably induce the instability of forest productivity under climate change. The most significant decrease (p<0.01) of CWC is observed primarily in evergreen broadleaf forest in the tropics, implying an increasing instability of the most important carbon sink in terrestrial ecosystem.

Receiver Function Analysis Reveals Lateral Variations in Temperature and Water Content in the Mantle Transition Zone Beneath Eastern North America

AbstractUsing recently collected high‐resolution seismic data along a dense linear transect across Ohio, West Virginia, and Virginia (called Mid‐Atlantic Geophysical Integrative Collaboration (MAGIC) profile), we analyze P‐to‐S receiver functions to investigate the undulations of the mantle transition zone (MTZ) discontinuities (410‐ and 660‐km) beneath the central Appalachian region. Our results incorporating the effects of local crustal and mantle structures suggest shallowing of both the 410‐ and the 660‐km discontinuities from the northwest (inland) to the southeast (coast) along MAGIC profile. Hydro‐thermal upwelling beneath the eastern U.S. coastal plain due to a hydrated MTZ and hot upwelling return flow associated with the descending lower mantle Farallon slab is consistent with our observations of MTZ structure considering 3D velocity heterogeneity. The inferred hydrous hot upwelling rising into the upper mantle may trigger dehydration melting atop the 410‐km discontinuity, which may help to explain the presence of a low velocity upper mantle anomaly beneath the region today.

Quantitative study on the influence of fly ash content, saturation degree and interface transition zone on the permeability of cement-based materials

The interfacial transition zone (ITZ) and fly ash content affect the transmission performance of concrete by altering its pore structure, while varying water content also has distinct effects on transport characteristics. Therefore, this paper investigates the effects of ITZ, fly ash content, and saturation degree on the gas transport performance of concrete materials through gas penetration tests, mercury injection tests, scanning electron microscopy (SEM), and backscattered electron (BSE) imaging. The influences of these factors on the intrinsic permeability of concrete materials are quantitatively analyzed through methods such as parallel test comparative analysis, regression analysis, function fitting, and fixed parameter analysis. The results indicate that the incorporation of fly ash can refine the pore structure of concrete, but it also leads to an increase in intrinsic permeability. The relationship between saturation degree of concrete and intrinsic permeability conforms to an exponential function. Under the same volume fraction, the intrinsic permeability of ITZ is hundreds of thousands of times higher than that of mortar matrix.

Spectroscopic behavior differences between lumazine and alloxazine in the DMSO-water mixture

The absorption and emission spectra were investigated for lumazine, alloxazine and their cyanated or fluorinated derivatives, respectively. The spectroscopic properties were modulated by varying water concentration in dimethyl sulfoxide (DMSO). Some intriguing experimental results were found for the samples containing 65 % of water and 35% of DMSO. This finding is consistent with previously published molecular dynamics (MD) simulations confirming the concept of the ‘local bulk’ model. In this case, a notable decrease in absorption and emission intensities was registered, even larger than the water quenching observed in other cases. The changes in midrange DMSO concentrations could be explained by the formation of local solvents structures as predicted by MD, specifically the formation of DMSO·2H2O dimers. Experimentally, the cyano-substituted lumazine has shown a remarkable sensitivity to DMSO concentration. The spectroscopic measurements were interpreted using the density functional theory where the implicit DMSO solvent model was combined with explicit water molecules. Together with its enhanced water solubility, the cyanated lumazine derivate could be used for non-destructive DMSO detection in vitro for applications such as drug uptake monitoring, since DMSO is often used in pharmaceutical practice.

Experimental and numerical studies of dynamic variation of liquid water and water vapor flow in the vadose zone

In arid and semi-arid regions, the depth of water table has a significant effect on evaporation. The soil in these regions is unsaturated, and the transport of liquid water and water vapor is accompanied by variation of the water table depth. In this study, we designed a laboratory experimental apparatus to conduct evaporation experiments of soil under shallow and deep water table conditions through continuous monitoring of water content and temperature variation in the vadose zone. A numerical model was used to simulate the coupled transport of liquid water, water vapor and heat in the vadose zone under two different water table elevations. The experimental and numerical results were in good agreement. Liquid water and water vapor fluxes driven by pressure head and temperature gradient were calculated and analyzed to illustrate the distribution of the water content. Both isothermal liquid flux and thermal vapor flux dominates the variation of water content. By determining the location of the evaporation front and analyzing its dynamic variation, we found that the evaporation front ranged from the surface to a depth of 2.5 cm under a shallow water table. For a deep water table, the evaporation front was nearly at a constant depth of 15 cm.

Statistical and Predictive Analyses of the Strength Development of a Cement-Treated Clayey Soil

The mechanical efficiency of soil stabilization with cement is mainly controlled by various parameters, namely, the amount of binder, the compaction soil state and the curing conditions. The strength of the treated soil is the result of a complex combination of several factors that condition the physicochemical processes involved in cement hydration, which are difficult to monitor. The objective of this study is to identify the relevant parameters governing the bonding in cement-treated soil and suggest a predictive model for strength evolution using these parameters as input. To this purpose, an extensive testing program is presented to assess the impact of the initial water content (11–18%) and dry density (1.6–1.87 Mg/m3) as well as cement dosage (3 and 6%) in sealed curing conditions for 0, 7, 28 and 90 days. The water content variation, the total suction and the compressive strength were measured after different curing durations. The experimental results are first discussed in the parameters’ space, and then through a principal components analysis to overcome the complexity due to the parameters’ interdependency. The PCA revealed that the cement dosage explained 40% of the dataset variance, the remaining 60% being related to a combination of the initial state and curing time. Finally, a predictive model based on an artificial neural network was developed and tested. The predicted results were excellent, with an R2 of +0.99 with the training data and +0.93 with the testing data. These results should be improved by extending the dataset to include different soils and additional compaction conditions.

Numerical analysis of the impacts of rainfall on permafrost-related slope stability on the Qinghai–Tibet Plateau

Study regionThis study interrogates a landslide in ice-rich permafrost region in the Eastern Qinghai–Tibet Plateau, China. Study focusClimate warming has increased the frequency and intensity of rainfall events, changing hydrothermal processes and the soil mechanical properties, thus affecting slope stability in permafrost region. The purpose of this paper is to elucidate the variations in soil volumetric water content (VWC) which may influence the mechanical properties of unstable slopes in ice-rich permafrost region under different rainfall conditions. New hydrological insights for the regionThis paper integrates the rainfall infiltration boundary conditions and Mohr–Coulomb criterion into a thermo–hydro–mechanical (THM) model and analyzes a landslide case in the permafrost regions. The results show that the THM model can effectively account for the impacts of VWC variation under different rainfall conditions. The influence of rainfall on the VWC diminishes as depth increases, with a more pronounced effect observed at depths less than 1 m. At depths exceeding 1 m, the impact is relatively minor. Under the condition of low-intensity, long-duration rainfall, with accumulated precipitation exceeding 60 mm, the cohesion and internal friction angle decrease to 4.2kPa and 8.1°, respectively, with a deep-layer integral slippage. In contrast, under the condition of high-intensity, short-term rainfall, the accumulated rainfall exceeds 75 mm and the internal friction angle decreases from 39° to 26°, with shallow-layer slippage. The results add on to our understanding engineering problems and periglacial geomorphic processes under the influence of climate warming.

Similarities and Differences in the Earth’s Water Variations Signal Provided by Grace and AMSR-E Observations Using Maximum Covariance Analysis at Various Land Cover Data Backgrounds

ABSTRACT The study presents a compatibility analysis of gravimetric observations with passive microwave observations. Monitoring the variability of soil water content is one of the essential issues in climate-related research. Total water storage changes (ΔTWS) observed by Gravity Recovery and Climate Experiment (GRACE), enables the creation of many applications in hydrological monitoring. Soil moisture (SM) is a critical variable in hydrological studies. Advanced Microwave Scanning Radiometer (AMSR-E) satellite products provided unique observations on this variable in near-daily time resolutions. The study used maximum covariance analysis (MCA) to extract principal components for ΔTWS and SM signals. The analysis was carried out for the global area, dividing the discussion into individual continents. The amplitudes of gravimetric and microwave signals were computed via the complex empirical orthogonal function (EOF) and the complex conjugate EOF* to determine the regions for detailed comparison. Similarities and differences in signal convergence results were compared with land cover data describing soil conditions, vegetation cover, urbanization status, and cultivated land. Convergence was determined using Pearson correlation coefficients and cross-correlation. In order to compare ΔTWS and SM in individual seasons, ΔTWS observations were normalized. Results show that naturally forested areas and large open spaces used for agriculture support the compatibility between GRACE and AMSRE observations and are characterized by a good Pearson correlation coefficient &gt;0.8. Subpolar regions with permafrost present constraints for AMSR-E observations and have little convergence with GRACE observations.

Assessing rainfall-induced wetting band depth for stability analysis of unsaturated soil slopes

Because of factors such as plant root action, soil capillary action, and evapotranspiration, the soil near the surface of a slope tends to be drier and in an unsaturated state. However, when rainfall infiltrates the soil, the soil near the surface can become saturated, creating a wetting band that may trigger shallow landslides on the slope. This study performed transient finite element seepage and slope stability analyses on unsaturated soil slopes during rainfall. The analysis considered a representative rainfall pattern observed in Taiwan from 2010 to 2022, accounting for potential impacts of climate change. The objective of this study was to explore the impact of wetting band development on the stability of unsaturated soil slopes under rainfall conditions. Additionally, the investigation aimed to analyze the variations in pore water pressure and volumetric water content throughout the rainfall process. These analyses were conducted to determine the slope safety factor and investigate the relationship between the wetting band and the potential sliding surface. The results showed that the soil pore water pressure and water content near the surface of the slope were highly influenced by rainfall. The wetting band gradually extended downward from the surface with increasing rainfall duration, resulting in an increased wetting band depth (WBD), while the potential sliding surface approached the slope surface. When the safety factor was at its lowest, the potential sliding surface intersected the edge of the wetting band and was included within the range of the wetting band. This observation indicates a significant relationship between the potential sliding surface and the evolution of the wetting band during slope failure at the moment of minimum safety factor. The study also observed that water infiltration near the toe of the slope was more rapid, leading to a deeper wetting band at this particular location.

A Study on the Sensitivities of an Ice Protection System Combining Thermoelectric and Superhydrophobic Coating to Icing Environment Parameters

The hybrid Ice Protection System combining thermoelectric and superhydrophobic coating is efficient and benefits from low-energy consumption. In order to explore the application details of superhydrophobic coating, this paper investigated the sensitivities of the Ice Protection System parameters including the range of the superhydrophobic coating, heating range and power to icing environmental parameters. In this paper, an icing wind tunnel test was adopted to study the performance of this Ice Protection System under different icing conditions, as well as the influence of the superhydrophobic coating range, heating range and power variation on ice protection. The results showed that the superhydrophobic coating is effective only when it covers the droplet impingement area, with the heating power requirement emerging as a critical design consideration that is extremely sensitive to environmental temperature changes. Additionally, median volumetric diameter determines the protection area to be protected, while liquid water content variation has little effect on the designed Ice Protection System in contrast.

Temperature and soil moisture control CO2 flux and CH4 oxidation in urban ecosystems

Climate-driven shifts in soil temperature and soil moisture are crucial factors that control the ecosystem-atmosphere greenhouse gas (GHG) balance. In the present study, the relationship between CO2, CH4 fluxes and soil moisture content and temperature sensitivity was examined in three dominating types of urban ecosystems: grassland, city park and arable land. The analysis was based on the field measurements at biweekly intervals over a year using a static closed chamber method in Wroclaw urban area, Poland. The observed patterns of land-atmosphere CO2 and CH4 exchange varied across land cover types and were strongly influenced by seasonal variations in temperature and soil water content. Emission of CO2 from grassland and the city park was two times higher than from the arable land. The calculated CH4 oxidation rate was one and half times higher (p < 0.05) under grassland and the city park as compared to arable land.The estimated Q10 values ranged between 1.68 and 1.79 for CO2 and from 1.26 to 1.49 for CH4, depending on the ecosystem type. The temperature sensitivity of soil respiration decreased when the temperature was above 24.5 °C across the moisture gradient from 20 to 25 % m/v. Results suggest that despite the urban areas with agricultural land use revealed the lowest CO2 fluxes compared to grassland and city park, the former showed the lowest seasonal mean CH4 oxidation. This indicates that with ongoing warming, the higher Q10 of CO2 production vs. CH4 oxidation will further shift the carbon balance towards the source and this shift will be especially critical for arable lands in urban areas.

Relating side scan sonar backscatter data to geotechnical properties for the investigation of surficial seabed sediments

Side scan sonar is a common tool for seafloor imaging and surveying due its efficiency and high resolution. The backscatter information from side scan sonar enables to identify sediment types and seabed roughness, often used to study sediment dynamics. Theory suggests that side scan sonar backscatter can be correlated to the geotechnical properties of the seabed surface. This could enhance the prediction of erodibility and efficiency of seabed sediment characterization, considering that side scan sonar can offer large spatial coverage in a short time. In this study, high-frequency (1000 kHz) side scan sonar backscatter data, sediment samples, and in-situ seabed strength profiles were collected of the seabed surface at ten locations. Statistical analysis of the backscatter data compared with geotechnical data showed trends between mean backscatter, soil strength, and textural sediment properties. Generally, mean backscatter increased when sediment strength and mean grain size increased and when water content and fines content decreased. However, roughness from bedforms, the presence of oysters, shell hash as well as variations in water content (i.e., porosity) of the seafloor heavily influenced the backscatter and sometimes masked any relationships with the strength properties directly.

A theoretical model on unfrozen water content in soils and verification

Phase transition of pore water is a fundamental reason for frost heave in cold regions. Therefore, studying the variation in unfrozen water content is of great significance for understanding the freezing process of pore water and revealing the freezing mechanism in soils. In this study, a prediction model for unfrozen water content was established based on a probabilistic ice-forming model. To determine the heterogeneous nucleation rate, which is the key variation in the probabilistic model, the relationship between the water film thickness and temperature variation in the soil was characterized based on the improved premelting theory. In this process, the equivalent particle size and density of impurities on the surface of the particles were determined by introducing the particle size distribution curve and average accumulation mode of the particles. Based on the heterogeneous nucleation mechanism of ice crystals and the variation in the water film, a relationship between the heterogeneous nucleation rate and temperature was established. Subsequently, a method for calculating the equivalent contact angle related to pore water in soils was presented. The results showed that the heterogeneous nucleation rate and equivalent contact angle are positively and negatively correlated with the equivalent particle size at the same temperature, respectively, and the angle decreases with increasing solution concentration. Furthermore, the experimental data of 10 different soils showed that the variation in water content obtained by our model was in good agreement with the experimental values, particularly during the stage of rapid water phase change. The study developed an effective correlation among heterogeneous nucleation rate and equivalent contact angle of pore water and physical properties of soil, by combining crystallization theory and premelting theory, which provided a new way to explain water freezing and predict unfrozen water content in soils.

Continuous ground monitoring of vegetation optical depth and water content with GPS signals

Abstract. Satellite microwave remote sensing techniques can be used to monitor vegetation optical depth (VOD), a metric which is directly linked to vegetation biomass and water content. However, these large-scale measurements are still difficult to reference against either rare or not directly comparable field observations. So far, in situ estimates of canopy biomass or water status often rely on infrequent and time-consuming destructive samples, which are not necessarily representative of the canopy scale. Here, we present a simple technique based on Global Navigation Satellite Systems (GNSS) with the potential to bridge this persisting scale gap. Because GNSS microwave signals are attenuated and scattered by vegetation and liquid water, placing a GNSS sensor under a vegetated canopy and measuring changes in signal strength over time can provide continuous information about VOD and thus on vegetation biomass and water content. We test this technique at a forested site in southern California for a period of 8 months. We show that variations in GNSS signal-to-noise ratios reflect the overall distribution of biomass density in the canopy and can be monitored continuously. For the first time, we show that this technique can resolve diurnal variations in VOD and canopy water content at hourly to sub-hourly time steps. Using a model of canopy transmissivity to assess these diurnal signals, we find that temperature effects on the vegetation dielectric constant, and thus on VOD, may be non-negligible at the diurnal scale or during extreme events like heat waves. Sensitivity to rainfall and dew deposition events also suggests that canopy water interception can be monitored with this approach. The technique presented here has the potential to resolve two important knowledge gaps, namely the lack of ground truth observations for satellite-based VOD and the need for a reliable proxy to extrapolate isolated and labor-intensive in situ measurements of biomass, canopy water content, or leaf water potential. We provide recommendations for deploying such off-the-shelf and easy-to-use systems at existing ecohydrological monitoring networks such as FluxNet or SapfluxNet.