We present a model of indoor residential water use that estimates water demand and conservation potential by end use for a target community by simulating indoor water end use events at a household level. The model uses end use event data from a set of representative residential households to simulate a larger community and advances existing end use models by: 1) accounting for an expanded set of indoor water end uses; 2) considering the variability in flowrates, durations, and volumes for end use events over different days of the week; and 3) providing a generalized approach for simulating indoor water usage and potential conservation at the city level. The model simulates residential water use behavior in individual households by randomly sampling water end use events for different end use types for each day of the week and then aggregating the sampled water end use events per day to estimate the daily water use per household. We used the model to evaluate a set of technological and behavioral conservation actions to quantify the conservation potential in each simulated household as well as aggregated to the city level. We evaluated the performance of the model in predicting the observed average daily water use of households in Logan City, Utah, USA and compared against other common water demand models to demonstrate the model’s reliability. The results of this paper are reproducible using openly available code and data, representing an accessible platform for advancing water demand modeling using detailed water end use data.

In contrast to most seagrass meadows where seawater carbonate chemistry generally shows strong diel variations with a higher pH during the daytime and a lower pH during nighttime due to the alternation in photosynthesis and respiration, the seagrass meadows of the inner lagoon on Dongsha Island had a unique diel pattern with an extremely high pH across a diel cycle. We suggest that this distinct diel pattern in pH was a result of a combination of total alkalinity (TA) production through the coupling of aerobic/anaerobic respiration and carbonate dissolution in the sediments and dissolved inorganic carbon consumption through the high productivity of seagrasses in overlying seawaters. The confinement of the semienclosed inner lagoon may hamper water exchange and seagrass detritus export to the adjacent open ocean, which may provide an ideal scenario for sedimentary TA production and accumulation, thereby forming a strong capacity for seagrass meadows to buffer ocean acidification.

Today's global challenges, like climate change and urbanization, combined with the growing population in urban areas have exposed conventional urban stormwater infrastructures to a great risk. Although an emerging need for a change in the urban stormwater managerial paradigm has shifted the decision-makers attention to add new objectives to the stormwater management traditional regulations, there are still limited proper solutions to accommodate the urban runoff dynamics over the watershed and enable an adaptive, distributed and sustainable control of stormwater infrastructures. These concerns can be resolved if intelligence is added to the conventional urban systems to balance the network flow dynamics and environmental demand. This paper provides a conceptual discussion to investigate a novel high-performance, adaptive, and intelligent stormwater control optimization architecture as a sustainable solution against the varying environment.

Compound dry and hot extremes (CDHE, such as recent summers 2015, 2018 and 2022 in Europe) have wide ranging impacts: Heat exacerbates moisture shortages during dry periods whereas water demand rises. Climate change will likely increase the intensity, frequency, and duration of CDHE events in Europe. However, current studies focus on drivers and impacts in coarse-resolution global climate models and likely miss spatial details of CDHE characteristics. To overcome this issue, we exploit a regional 50-member single-model initial condition large ensemble (SMILE) at 12 km spatial resolution. Hence 1000 model years per 20 year-periods provide an extensive database of CDHE and robust estimations of their occurrence changes across Europe in high geographical detail. CDHE occurrences are investigated in a current climate and at two global warming levels (+2 °C, +3 °C). We identify Northern France, Southern Germany, Switzerland, Southern Ireland, and the western coasts of the Black Sea with currently low CDHE frequencies as emerging hotspots. These regions experience a tenfold occurrence increase under global warming conditions. Apart from Western Europe, temperature is the dominant contributor to frequency increases. Furthermore, tail dependencies strengthen in regions with high CDHE frequency increases. In European agricultural areas, soil moisture shows very strong negative correlations with CDHE extremeness. Last, our results suggest a halving of CDHE in a +2 °C world compared to a +3 °C world, highlighting the necessity of climate mitigation with respect to this hazard type.

The flow of CO2 foam for mobility control in porous media is dictated by the foam texture, or bubble density, which is commonly expressed as the number of bubbles per unit of flowing gas. In most high-pressure laboratory studies of foam in porous media, the local foam texture cannot be determined due to opaque flow systems. Here, we unlock real-time foam texture dynamics at high pressure (100 bar) by utilizing a realistic pore network with an extended field of view. We identified snap-off as the dominant foam generation mechanism, with additional fining of foam texture caused by backward foam propagation. Foam coalescence during continuous CO2 injection resulted in large gas channels parallel to the general flow direction that reduced the overall foam apparent viscosity. A large fraction of the CO2 foam remained trapped (X_t > 0.97) and stationary in pores to divert CO2 flow and increase sweep efficiency. The gas mobility was calculated from the fraction of trapped bubbles at the pore-scale, and the apparent foam viscosity was in agreement with similar injection test performed at core-scale. Hence, improved understanding of CO2 foam texture evolution (n_f) can strengthen the validation of numerical foam models for physical upscaling of flow phenomena, instrumental in the development of field scale implementation of CO2 foam for in carbon utilization and storage applications.

Fractures play an important role in transport in unconventional formations. Both matrix and fracture network in fractured media contribute to the effective permeability (keff). In this study, we investigate the interaction between matrix and fracture permeabilities (km and kf) via the percolation-based effective-medium approximation (P-EMA). We theoretically determine the keff value at different fracture densities and compare our results with two- and three-dimensional numerical simulations. We found that the P-EMA estimated the effective permeability accurately in the matrix-fracture systems studied here. Further investigations are needed to better understand how the parameters of the P-EMA including scaling exponent and critical fracture density might vary from one fractured reservoir to another.

A physically based analytical model is formulated to simulate the thaw depth of active layer under changing boundary condition of soil heat flux. The energy conservation statement leads to a nonlinear integral equation of the thaw depth using an approximate temperature profile as an analytical solution of the diffusion equation describing the heat transfer in the active layer. The time-varying soil surface heat flux is estimated using non-gradient models when field observations are not available. The proposed model was validated against field observations at three Arctic forest and tundra sites. The simulated thaw depth and soil temperature profiles are in good agreement with observations hinting the potential for model application at larger spatial scales.

Marine heatwave (MHW) characteristics - such as frequency, intensity and duration - are increasing, largely due to global warming. However, while corresponding marine cold spell (MCS) characteristics have decreased over most regions, importantly, concomitant changes in MHW and MCS characteristics remain unclear. Here, we provide a comparative global assessment of these changes based on satellite sea surface temperature (SST) observations over 1982-2020. Across the planet, we find distinct differences in mean MHW and MCS metrics. Furthermore, decreasing trends in MCS characteristics are not necessarily aligned with increasing trends in MHW characteristics. While differences in intensity trends are mainly explained by SST variance trends, differences in exposure trends are less clear. Overall, decreasing MCS exposure and intensities are found to be largely driven by warming SST, rather than changes to SST variance, so it is expected that MCS will continue to diminish in their frequency, intensity and duration under global warming.

Anthropogenic subsurface urban heat islands (SUHIs) in groundwater under cities are known worldwide. SUHIs are potentially threats to springs because much spring fauna, like trout, amphipods, and rare plants, is cold stenothermal. The city of Minneapolis, Minnesota, USA, has a SUHI documented by the temperature of an underground spring, dubbed “Little Minnehaha Falls,” inside Schieks Cave, which is located 23 m below the central core of the city. In 2000 the temperature of that spring was elevated 11°C above regional background groundwater temperatures (8°C) at this latitude (45°N). A thermometric survey of the cave and nearby tunnel seepages in 2007 found that an abandoned drill-hole through the bedrock ceiling of the cave was discharging groundwater with a temperature of 17.9°C. By comparison, groundwater in the deep water-table below the cave was closer to natural background temperatures for the region. The unusually warm groundwater was thereby localized to the strata above the cave. This is the strongest signal of anthropogenic groundwater warming in the state of Minnesota and is attributed to vertical heat conduction from basements and pavements. Minneapolis is unique among SUHIs in that a cave forms a natural collection gallery deep below the city surface, whereas the literature is almost exclusively based on data from observation wells.

A document by Jiali Zhang. Click on the document to view its contents.

There has been increasing realization that the non-traditional Coriolis force terms may have a significant effect on convective circulation and organization in the tropics. In this talk, we introduce the concept of the net Coriolis force of a fluid dynamical flow. In order to compute the net Coriolis force, we assume incompressible flow - and therefore incompressible net Corolis force. Through the Leray projection we are able to construct, both, the pressure needed to maintain an incompressible force, and the net Coriolis force, itself. We explore the effects of the net Coriolis force on basic flows by decomposing the velocity field using the Helmholtz decomposition, and we describe poloidal and horizontal flows separately. We then compute the net Coriolis force associated with the Traditional Corolis terms (proportional to the sine of latitude) and, separately, the net Non-Traditional Coriolis terms (proportional to the cosine of latitude). We show that all poloidal circulations - which are flows which lack a vertical component of vorticity - are in vertical gesotrophic balance. Therefore, the pressure induced by such flows is simply computed without the need to invert a Laplacian. Using the Dynamics of Non-rotating Updraft Tori (DoNUT), which is a polodial circulation framework introduced by Igel & Biello (2020) to describe the full kinematic circulation of atmospheric convection, we show that the net non-traditional Coriolis force has zero component in the vertical direction, is westward in the regions of upward flow, and recirculates eastward poleward of the upward flow. The resulting circulations lead to vertical/westward oriented momentum flux from the resulting Reynold’s stress terms. We will conclude by discussing implications of these circulations for tropical convective organization.

Crater morphology and surface age of asteroid (162173) Ryugu are characterized using the high-resolution images obtained by the Hayabusa2 spacecraft. Our observations reveal that the abundant boulders on and under the surface of the rubble-pile asteroid affect crater morphology. Most of the craters on Ryugu exhibit well-defined circular depressions, unlike those observed on asteroid Itokawa. The craters are typically outlined by boulders remaining on the rim. Large craters (diameter >100 m) host abundant and sometimes unproportionally large boulders on their floors. Small craters (<20 m) are characterized by smooth circular floors distinguishable from the boulder-rich exterior. Such small craters tend to have dark centers of unclear origin. The correlation between crater size and boulder number density suggests that some processes sort the size of boulders in the shallow (<30 m) subsurface. Furthermore, the crater size-frequency distributions (CSFDs) of different regions on Ryugu record multiple geologic events, revealing the diverse geologic history on this 1-km asteroid. Our crater counting analyses indicate that the equatorial ridge is the oldest structure of Ryugu and was formed 23-29 Myr ago. Then, Ryugu was partially resurfaced, possibly by the impact that formed the Urashima crater 5-12 Myr ago. Subsequently, a large-scale resurfacing event formed the western bulge and the fossae 2-9 Myr ago. Following this process, the spin of Ryugu slowed down plausibly due to the YORP effect. The transition of isochrons in a CSFD suggests that Ryugu was decoupled from the main belt and transferred to a near-Earth orbit 0.2-7 Myr ago.

Environmental observatory networks (EONs) provide information to better understand, model and forecast the spatial and temporal dynamics of Earth’s biophysical process. Consequently, representativeness analyses of EONs are important to provide insights for improving EONs’ management, design, and interpretation of their value-added products (e.g., datasets, model predictions). We assessed the representativeness of registered FLUXNET sites (n=41, revised on September 2018) across Latin America (LA), a region of great importance for the global carbon and water cycles, which represents nearly 13% of the world’s land surface area. Representativeness analyses were performed using a 0.05o spatial grid for multiple environmental variables, gross primary productivity (GPP) and evapotranspiration (ET) across LA. Our results showed a potential spatial representativeness of 34% of the surface area for climate properties, 36% for terrain parameters, 34% for soil resources, and 45% when all aforementioned environmental variables were summarized into a principal component analysis. Furthermore, there was a 48% potential representativeness for GPP and 34% for ET. Unfortunately, data from these 41 sites is not all readily available for the scientific community, limiting synthesis studies and model benchmarking/parametrization. We discussed the need to enhance interoperability, promote the participation of active/inactive sites to share information with local, regional and international networks, and promote monitoring efforts across this region of the world to increase the accuracy of regional-to-global data-driven products.

On 16 December 2017 a chain mass movement, started as a rockslide, produced a debris and mud flow which channelized in the Burritos River. The flow reached and flooded the Santa Lucia village (-43.41°/-72.37°) destroying 50% of the urban area and killing 22 people. This fatal event resulted as a conjunction of geologic, meteorological and glaciological variables: Highly altered volcanic rocks with deep vertical fractures and steep slopes in the Yelcho Range; an intense precipitation event 30 hours prior the rockslide of up to 124.8 mm in one day with a high zero-degree isotherm elevation; an ice-cored lateral moraine deposit under the headwall plus hyper saturated soils downhill near the Burritos River. The role of a proglacial lake has been discussed, nonetheless, current studies argue that the main liquid inputs could have been pre-existing water in saturated soil. In this study we analyzed satellite imagery available on the web, including Sentinel 2 and Landsat scenes. Based on the Public Chilean Glacier Inventory, we quantify the retreat of glaciers laying on the eastern flank of the Yelcho Range, west of the Santa Lucía village. On a time-span of 33 years (1987 to 2020), we estimate over 650 m of glacial retreat plus an accelerated retreat rate up to 30 m/yr for the last decade. Such glacier shrinkage coupled with increasing local temperatures may lead to the genesis of more proglacial lakes, enhancing the odds of chain mass movements, favoring the interaction between rockslides and glacial lakes. Our results show an example of a relatively simple analysis that can be performed with basic tools and with no further expenses. The proper understanding of glacial landscape evolution with time and its response to extreme climatic events is essential to prevent human loses, as these events will be more frequent due to the current climate change context. For that purpose, further work aims to clarify more hidden variables in the region, such as the number of proglacial lakes, steep slopes on headwalls, highly eroded slopes, among others, in order to enlarge the local knowledge linked to one of many components involved on a natural disaster, thus, increasing the resilience of communities whom are still occupying the affected area after the Santa Lucía landslide disaster.

Dunes dominate the bed of sandy rivers and they respond to flow by changing shape and size, modifying flow and sediment transport dynamics of rivers. Our understanding and ability to predict dune adaptation, particularly dune growth and decay, remains incomplete. Here we investigate dune growth from an initial flatbed in a laboratory setting by continuously mapping the 3D bed topography using a line laser scanner combined with a 3D camera. High-resolution profiles of flow velocity and sediment concentration providing both bedload and suspended sediment fluxes were obtained by deploying Acoustic Concentration and Velocity Profiler technology. Our analysis reveals that the magnitude of the dune slipface angle, which determines flow separation and controls turbulence production, adjusts to the imposed flow at time scales similar to the evolution of dune height and length. The initiation of a flow separation zone intensifies through scour, and results in acceleration of the dune growth. Gradients in sediment transport and the rate of dune growth are inherently linked to spatial variations in slipface angles. During dune growth, the slipface angle evolves differently than the ratio of dune height to length, which immediately reaches its equilibrium value after dune initiation.

Different spectroscopy methods such as visible near-infrared (Vis-NIR) spectroscopy have proven to provide useful information on soil physical and chemical properties. The majority of previous studies have focused on multivariate regression methods such as partial least squares regression (PLSR) to predict soil characteristic features from soil spectra. The objective of these efforts was to provide precision data for agricultural and land management practices where the knowledge about the soil differences in each part of the field can be used for variable-rate irrigation, seeding, liming, fertilising and pesticide application. Since the currently available machines can only apply few (less than 10) variable classes of seed, fertiliser, etc., using soil classification seems to be a more appropriate option compared to regression. As a part of Danish National Soil Survey in 1980s, 2460 soil samples were collected from 789 soil profiles in 4 depths (0-30, 30-60, 60-100 and 100-200cm) throughout Denmark (some profiles did not have samples from all 4 depths) and tested for several soil characteristics including complete soil texture, organic carbon content and calcium carbonate in the lab. Based on these soil characteristics, all soil samples were classified into 8 soil types or 12 soil classes in the Danish Soil Classification System (JB system). Later the Vis-NIR spectra of samples were measured using a FOSS DS2500 spectrometer in the range of 350-2500nm. Partial least squares and support vector machines discriminant analyses (PLS-DA and SVM-DA, respectively) were used to calibrate and cross-validate classification models where soil Vis-NIR spectra were used to classify each sample from each depths into its corresponding JB soil type and soil class. The results show excellent classification accuracy and specificity (>80% and >90%, respectively) for samples from the same depths and when samples from all depths were combined. We found that the high false negative rate (low sensitivity) was mainly due to the models classifying samples in the neighbouring classes of the actual class (e.g. classifying a sample in JBC 2 as belonging to JBC 1 or JBC 3). This clearly indicates that calibrating the classification model on the uncertain hydrometer data (with 1.4-2% reproducibility error) was the main reason for classification of samples in the neighbourhood of the actual class. In conclusion, given the highly uncertain reference methods for soil classification, using Vis-NIR spectroscopy with PLS-DA provides a very rapid, inexpensive, and highly reliable method for soil texture classification on a national scale.

Gas and vapour emissions from subglacial or subnivean volcanoes are capable of melting voids and passageways, here termed glaciovocanic caves and chimneys, in the overlying ice/snow. Glaciovolcanic caves (sub-horizontal) and chimneys (vertical) have been documented within a variety of volcanic regions around the world, with their formation sometimes preceding volcanic eruptions. Studying the formation and evolution of glaciovolcanic caves and chimneys and their relation to changes within the associated volcanic and glacial systems, therefore has potential to inform glaciovolcanic hazard assessments. In 2016, glaciovolcanic chimneys were discovered within Job Glacier in the Mt. Meager Volcancic Complex, British Columbia, Canada. The hypothesis that the chimneys formed as a result of glacier thinning, rather than due to an increase in volcanic activity, has yet to be tested. Here we seek to describe the morphology of these glaciovolcanic features, with respect to glaciological conditions and geothermal heat fluxes, using analytical models. By adapting existing analytical models of subglacial hydrological channels to account for the flow of geothermal gases instead of water, we derive the opening and closure rates for glaciovolcanic caves and chimneys. We use idealized glacier geometries and simplified descriptions of the energy transfer between the geothermal gases and the ice walls to facilitate our analysis. Steady-state geometries are found by balancing the melt opening, internal energy loss and the closure due to ice creep, and presented as functions of glacier thickness and geothermal heat flux. Our analytical results will be used to guide numerical simulations with more complex geometries and transient glaciovolcanic conditions. A better understanding of these complex interactions will facilitate more effective assessment of potential precursory signals of volcanic activity.

The Patagonian Icefields (Northern Patagonia Icefield and Southern Patagonia Icefield) are the largest ice bodies in the Southern Hemisphere outside Antarctica. Nonetheless, little is known about their main meteorological and glaciological features (mean state, variability and trends) in present climate (last ~30 years). The lack of temporarily and spatially dense observational data in this area has imposed a limitation on the assessment of the atmosphere-cryosphere interaction, a key issue for understanding the past, present and future evolution of these ice bodies and more generally, the southern Andes cryosphere. In this work, we overcome the absence of surface data by modeling the present-day atmospheric surface conditions for southern Andes. We first use a regional climate model (RegCMv4) to dynamically downscale the ERA-Interim reanalysis at 10-km spatial resolution for the period 1980-2015. Then, we statistically downscale its outputs to a 450-m resolution grid. This meteorological forcing is used later as an input for a simplified surface mass balance model. The surface mass balance output is analyzed particularly for spatial and temporal variability as well as trends. This allows us to have a better understanding of the local-scale atmospheric control (i.e., surface temperature, solar radiation and precipitation) over the surface mass balance of Patagonian Icefields. In order to assess the large-scale control over the surface mass balance of Patagonian Icefields, time series of spatially-averaged modeled fields are projected upon main atmospheric fields obtained from ERA-Interim reanalysis. Main results show that years of relatively high (low) surface mass balance are associated with low (high) pressure anomalies near the Bellingshausen Sea, causing an anomalous cyclonic (anticyclonic) circulation that enhances (reduces) the westerlies impinging the Patagonian Icefields which in turn increments (decrements) the surface mass balance. Only weak correlations between the mass balance and the main atmospheric modes of variability (ENSO, PDO, SAM) were found, suggesting little dependency between these modes and the surface mass balance of the Patagonian Icefields.