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DOE OSTI2023

Model simulations of Plum Island Ecosystems LTER low marsh site using ELM-PFLOTRAN

Model simulations using the E3SM Land Model (ELM) coupled to the PFLOTRAN reactive transport model via the Alquimia interface. The simulations were conducted for a tidal salt marsh at the Plum Island Ecosystems LTER near Rowley, Massachusetts, USA. Model simulations were forced using site-specific tidal cycles and salinity, and the simulations used a biogeochemical reaction network including aerobic decomposition, sulfate reduction, iron reduction, and methanogenesis. Model outputs include simulated carbon stocks, carbon dioxide and methane fluxes, and porewater concentrations of key solutes related to sulfur, iron, and carbon cycling. The model simulations included a saline simulation (with tidal sulfate inputs), a fresh simulation (with low salinity and low sulfate inputs), and a saline simulation with lower vegetation productivity to represent the effect of salinity on vegetation. These simulations were conducted to demonstrate that a new model framework incorporating subsurface redox and biogeochemical interactions into a land surface model could reproduce measured surface greenhouse gas fluxes and biogeochemical dynamics in tidal marsh ecosystems, and to test whether including redox interactions in a land surface model would allow the model to resolve contrasts in biogeochemical cycling and greenhouse gas production between saline and freshwater wetlands.The data package includes gzipped tar archives (which can be expanded using standard tar and gzip utilities) of model outputs from three model configurations: saline subsurface and reduced vegetation productivity related to salinity; saline subsurface with vegetation productivity not reduced; and freshwater. Also included are code for the modified E3SM model, Alquimia interface, and PFLOTRAN reactive transport simulator in gzipped tar format; plain text parameter and configuration files; python code files for visualizing model output and defining model configurations; and model output, tide and salinity forcing, and configuration files in netCDF format. See the README.md file in the data package for a detailed description of all files contained in the package. All files are in netCDF (.nc), gzipped tar archive (.tar.gz or .tgz), or text (all other files).Updated: May 13, 2024. Model output, E3SM code, PFLOTRAN input files, and python codes for visualizing results were updated to reflect changes made for the manuscript revision. The updated archive reflects the code and model output from the final accepted manuscript. Changes included updated reaction parameters reflecting improved parameterization and additional comparisons with field measurements. E3SM code changes included better support for multiple grid cells and improved flow and transport parameterization.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2020

Big Sky Regional Carbon Sequestration Partnership (Phase III Final Scientific/Technical Report)

The Big Sky Carbon Sequestration Partnership (BSCSP) pursued a Phase III demonstration project at Kevin Dome in north central Montana. Kevin Dome covers approximately 700 square miles and is a naturally occurring CO 2 reservoir that is flanked by oil and gas fields. The carbon dioxide (CO 2 ) is in the upper Devonian Duperow (carbonate) formation and does not reach the spill point of the dome; therefore, the dome has potential as a CO 2 sequestration reservoir, a CO 2 supply, or as both if anthropogenic sources and enhanced oil recovery (EOR) operations are associated with the dome. Kevin Dome could potentially act as a buffer to continue accepting anthropogenic CO 2 when EOR flooding operations are interrupted or completed. The project objective was to produce one million tonnes of CO 2 from the gas cap of Kevin Dome, pipe it laterally, inject, and re-store it in the brine leg of the same formation to test the hub / buffer storage concept. This was to be accomplished by drilling up to five production wells, building a short pipeline and compression facilities, and drilling an injection well and several monitoring wells. BSCSP commenced outreach and site characterization activities including acquiring baseline data for near-surface insurance monitoring, acquiring 3-dimensional, 9-component surface seismic over the project area, drilling two test wells (one in the production area and one in the injection area), coring key intervals, and performing comprehensive logging. Well tests of those wells revealed two barriers to the project. The production (Danielson 33-17) well was perforated in multiple zones but failed to produce any significant CO 2 . This was despite being drilled in the near vicinity of a historic well that had produced 3700 MCF per day in a drill stem test. Modeling indicated that this was likely due to a phase change during production causing a temperature drop resulting in hydrate and/or water ice formation that clogged the formation. Tests of the injection zone (Wallewein 22-1) well indicated total dissolved solids (TDS) slightly below the EPA required 10,000 parts per million (ppm) for a Class VI underground injection control permit. While the project was initiated before Class VI rules were promulgated, and this was an experimental project (seemingly qualified for a Class V permit), the Environmental Protection Agency (EPA) indicated that injection would require a Class VI permit. The low salinity result was unexpected as contours plotted based on regional formation water quality data indicated an expected TDS above 20,000 ppm, and wells between the recharge zone and the Wallewein well tested above 10,000 ppm. Faced with the inability to obtain an injection permit, the demonstration project could not proceed. However, the project had generated valuable samples and data on a large natural analog including 32 sq. mi. of 3-D, 9-C seismic, 430 ft. of carbonate core covering seven different depositional environments taken from areas with, and without the presence of CO 2 , 30 ft. of core of two caprocks, a tight carbonate and an anhydrite, a full set of modern logs on both wells, and well tests. DOE decided to re-scope the project around completing studies utilizing this data. This report covers both the initial scope and the re-scope (Task / Section numbers preceded with an R). While the report covers a wide range of project activities, highlights of this work include: Development of a geostatic model using neural nets to match well logs to facies and using multi-waveform seismic to inform reservoir heterogeneity; Unique mechanical testing of permeability – stress relationship in two caprock materials; Development of full waveform inversion to generate a high resolution velocity model; Model development for dual permeability (fracture and matrix) systems to better account for matrix-matrix interactions; Joint seismic wave inversion (including the first quadr-joint inversion) exhibiting better imaging of a challenging reservoir zone in stiff rock; Core flow and core flood results on a reactive carbonate; and Innovative laboratory measurements of seismic response of fractured core as a function of fluid fill.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2020

Effects of salinity and pH on the spectral induced polarization signals of graphite particles

The electrical property of micrometre-sized graphite particles was investigated under different particle concentration, particle size, fluid conductivity and pH conditions. Due to its large internal electronic conductivity and ability to polarize under external potential field, significant enhancement of its spectral induced polarization (SIP) responses is observed when graphite is included in sand mixtures. While a small amount of graphite inclusion significantly increases the SIP response of its mixtures with sand, further concentration increase does not necessarily lead to a proportional increase of the SIP response. This is shown to be related to the formation of graphite aggregates at higher concentrations. Changes of fluid salinity have a significant effect on graphite's SIP behaviour. This includes a positive impact on normalized chargeability and imaginary conductivity, but a negative impact on chargeability and relaxation time constant. The effect of pH on the SIP response of graphite is small but shows consistent trend, where pH increase leads to a decrease of both the chargeability and relaxation time constant. The underlying cause of this effect is not clear.

58 GEOSCIENCES↗

DOE OSTI2022

Freshwater Flux Variability Lengthens the Period of the Low-Frequency AMOC Variability

Atlantic Meridional Overturning Circulation (AMOC) exhibits interdecadal to multidecadal variability, yet the extent to which the surface freshwater flux (FWF) variability affects the AMOC variability remains unclear. This study isolates the contribution of FWF variability in modulating AMOC through a partially coupled experiment, in which the FWF effect from the atmosphere and sea ice are disabled. It is demonstrated that the FWF effect can remarkably enhance the persistence of positive salinity anomalies in the Labrador Sea, and sustain the dense water formation that was initiated by the cold temperature anomalies. Therefore, the FWF variability serves as a positive feedback on AMOC and lengthens the period of the AMOC oscillation. Further lead-lag regressions of atmospheric and oceanic variables onto the AMOC time series illuminate that the persistent salinity anomalies are generated through two pathways: i) the phase lag between temperature and salinity anomalies in the Labrador Sea; and ii) a downstream propagation of extra high-salinity anomaly along the East Greenland Current, due to the reduced sea ice melting flux associated with an atmosphere forcing over the southern Greenland tip.

58 GEOSCIENCES↗

DOE OSTI2023

Hybrid Uses of High-Temperature Reservoir Thermal Energy Storage: Lessons Learned from Previous Projects

One of the critical challenges of the green energy transition is resolving the mismatch between energy generation provided by intermittent renewable energy sources such as solar and wind and the demand for energy. There is a need for large amounts of energy storage over a range of time scales (diurnal to seasonal) to better balance energy supply and demand. Subsurface geologic reservoirs provide the potential for storage of hot water that can be retrieved when needed and used for power generation or direct-use applications, such as district heating. It is important to identify potential issues associated with high-temperature reservoir thermal energy storage (HT-RTES) systems so that they can be mitigated, thus reducing the risks of these systems. This paper reviews past experiences from moderate and high-temperature reservoir thermal energy storage (RTES) projects, along with hot water and steam flood enhanced oil recovery (EOR) operations, to identify technical challenges encountered and evaluate possible ways to address them. Some of the identified technical problems that have impacted system performance include: 1) insufficient site characterization that failed to identify reservoir heterogeneity; 2) scaling resulting from precipitation of minerals having retrograde solubility that form with heating of formation brines; 3) corrosion from low pH or high salinity brines; 4) thermal breakthrough between hot and cold wells due to insufficient spacing. Proper design, characterization, construction, and operational practices can help reduce the risk of technical problems that could lead to reduced performance of these thermal energy storage systems.

energy storage↗

DOE OSTI2022

Auto Indexer for Percussive Hammers Final Report

Geothermal energy has been underutilized in the U.S., primarily due to the high cost of drilling in the harsh environments encountered during the development of geothermal resources. Drilling depths can approach 5,000 m with temperatures reaching 170 C. In situ geothermal fluids are up to ten times more saline than seawater and highly corrosive, and hard rock formations often exceed 240 MPa compressive strength. This combination of extreme conditions pushes the limits of most conventional drilling equipment. Furthermore, enhanced geothermal systems are expected to reach depths of 10,000 m and temperatures more than 300 °C. To address these drilling challenges, Sandia developed a proof-of-concept tool called the auto indexer under an annual operating plan task funded by the Geothermal Technologies Program (GTP) of the U.S. Department of Energy Geothermal Technologies Office. The auto indexer is a relatively simple, elastomer-free motor that was shown previously to be compatible with pneumatic hammers in bench-top testing. Pneumatic hammers can improve penetration rates and potentially reduce drilling costs when deployed in appropriate conditions. The current effort, also funded by DOE GTP, increased the technology readiness level of the auto indexer, producing a scaled prototype for drilling larger diameter boreholes using pneumatic hammers. The results presented herein include design details, modeling and simulation results, and testing results, as well as background on percussive hammers and downhole rotation.

15 GEOTHERMAL ENERGY↗

DOE OSTI2024

SimCCS 3.0 User GUIDE

Carbon Capture and Storage (CCS) is an important technology aimed at reducing CO 2 emissions and contributing to the mitigation strategies of climate change. The process involves three main steps: CO 2 capture, transport, and storage. Specifically, CO 2 is captured from industrial facilities, such as coal-fired power plants and natural gas processing plants. It is then transported through infrastructure networks, such as pipelines, rails, and ships, and injected into underground geological formations, such as depleted oil and gas reservoirs or deep saline aquifers, for permanent storage. The entire CCS value chain encompasses multiple components, including CO 2 sources, transport networks, and storage sites. The proper design of CCS transport infrastructure is an essential step for the deployment of CCS technology. However, the design is not a trivial process, as it presents many challenges and requires consideration of numerous economic, social, and environmental factors.

42 ENGINEERING↗

DOE OSTI2024

Multi-Scale 3D Imaging for Machine Learning Property Upscaling: Mt. Simon Sandstone Case Study

Petrographic properties of principal target reservoirs for carbon sequestration, such as the Mt. Simon Sandstone, are relevant to broad interest groups. The Mt. Simon Sandstone is a deep, saline, regionally extensive Cambrian sandstone, overlain by low permeability sealing formations, making it one of the viable geologic carbon storage reservoirs in the Midwestern US. Its thickness (exceeding 2400 ft in some localities), depth, and lateral extent, combined with high porosity and permeability make it a high-priority target of multiple ongoing geologic carbon sequestration efforts in the United States of America. The National Energy Technology Laboratory in Morgantown, West Virginia, has been engaged in characterization efforts of the Mt. Simon for over a decade, with a strong focus on Computed Tomographic data acquisition. Data generated during this period has been hitherto not accessible to the public. This archival effort focused on preservation of historical CT data and associated metadata, and facilitating their accessibility, culminating with the publication of the entire dataset on NETL’s Energy Data eXchange (EDX) and the associated Gill et. al (2024) paper.

Gill, Magdalena K.↗

NASA NTRS1987

A coupled dynamic-thermodynamic model of an ice-ocean system in the marginal ice zone

Thermodynamics are incorporated into a coupled ice-ocean model in order to investigate wind-driven ice-ocean processes in the marginal zone. Upswelling at the ice edge which is generated by the difference in the ice-air and air-water surface stresses is found to give rise to a strong entrainment by drawing the pycnocline closer to the surface. Entrainment is shown to be negligible outside the areas affected by the ice edge upswelling. If cooling at the top is included in the model, the heat and salt exchanges are further enhanced in the upswelling areas. It is noted that new ice formation occurs in the region not affected by ice edge upswelling, and it is suggested that the high-salinity mixed layer regions (with a scale of a few Rossby radii of deformation) will overturn due to cooling, possibly contributing to the formation of deep water.

Hakkinen, Sirpa↗

DOE OSTI2024

Active Reservoir Management Engineering and Evaluation Summary – Brine Extraction and Storage Test Phase II Final Report – Volumes 1-3

The Energy & Environmental Research Center (EERC) conducted a multiyear program over two phases to perform a field study of the potential efficacy of formation water extraction during carbon dioxide (CO 2 ) injection for CO 2 storage as a means of improving efficiency and/or effectiveness. Phase I was a 2-year study on potential methodologies for a field study of pressure management, culminating in site selection and experimental and site design. Phase II was a 7-year effort that involved constructing site facilities, conducting experiments, and evaluating collected field data. The experimental portion was split into two collaborative components, one for the active reservoir management (ARM) experiment and a second component to host and demonstrate potential water treatment technologies appropriate for high-saline brine at the project site. The results of the overall project are expected to benefit future saline storage projects through validation of techniques that may reduce stress on sealing formations, increase storage capacity, and reduce area of review. The following report focuses on the Phase II ARM experimental implementation and results. A second companion report summarizes the results of the high-saline brine demonstrations.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2022

Dynamic stability of a crude oil/brine interface: Effect of anion type

The chemical composition of the aqueous phase plays an essential role in water-based enhanced-oil recovery processes. The aqueous phase ionic profile affects the snap-off response of a crude oil-brine system by linking it to the brine-crude oil interfacial rheology. In this work, we focus on the effect of the anion on the snap-off response. To this end, a sample of crude oil from the Minnelusa Sandstone formation in Wyoming was selected, and several aqueous solutions were prepared with salts containing sodium cation and different anions (chlorides, sulfates, and phosphates) at two ionic strength values, 0.6 M and 6 mM, as cases of high- and low-salinity water. Interfacial tension, interfacial viscoelasticity and interface stability were analyzed as functions of aging time using pendant drop, dilatational rheology, and liquid bridge techniques, respectively. Here the results show that solutions with higher ionic strength led to the formation of more rigid interfaces, i.e. higher elastic modulus, and faster formation kinetics. In the low-salinity regime, solutions with polyvalent anions produce more viscoelastic interfaces at faster rates than solutions with monovalent anions. Finally, an excellent correlation (R 2 greater than 0.97) between the relative stability of the interfacial film, predicted in liquid bridge tests, and the ratio of interfacial tension and interfacial elastic modulus was found.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2022

Freshwater Input and Vertical Mixing in the Canada Basin’s Seasonal Halocline: 1975 versus 2006–12

Abstract The Arctic seasonal halocline impacts the exchange of heat, energy, and nutrients between the surface and the deeper ocean, and it is changing in response to Arctic sea ice melt over the past several decades. Here, we assess seasonal halocline formation in 1975 and 2006–12 by comparing daily, May–September, salinity profiles collected in the Canada Basin under sea ice. We evaluate differences between the two time periods using a one-dimensional (1D) bulk model to quantify differences in freshwater input and vertical mixing. The 1D metrics indicate that two separate factors contribute similarly to stronger stratification in 2006–12 relative to 1975: 1) larger surface freshwater input and 2) less vertical mixing of that freshwater. The larger freshwater input is mainly important in August–September, consistent with a longer melt season in recent years. The reduced vertical mixing is mainly important from June until mid-August, when similar levels of freshwater input in 1975 and 2006–12 are mixed over a different depth range, resulting in different stratification. These results imply that decadal changes to ice–ocean dynamics, in addition to freshwater input, significantly contribute to the stronger seasonal stratification in 2006–12 relative to 1975. These findings highlight the need for near-surface process studies to elucidate the impact of lateral processes and ice–ocean momentum exchange on vertical mixing. Moreover, the results may provide insight for improving the representation of decadal changes to Arctic upper-ocean stratification in climate models that do not capture decadal changes to vertical mixing.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2026

A Review and Outlook on Experimental Advances and Innovations in Geological CO 2 Storage: Insights from Depleted Gas Reservoirs and Saline Aquifers

Geological storage of carbon dioxide (CO 2 ) in depleted gas reservoirs and deep saline aquifers is a key part of global decarbonization efforts. As carbon capture and storage advances toward commercial-scale deployment, the credibility and scalability of laboratory experiments are increasingly vital for guiding safe and effective field implementation. This review offers a comprehensive, cross-scale evaluation of experimental methodologies, including core flooding, high-pressure, high-temperature systems, microfluidic visualization, and emerging systems such as multilayer commingled/compartmentalized core flooding, 3D-printed micromodels, and AI-powered digital twins. These innovations are demonstrated to enhance representativeness, reproducibility, and real-time insight, thereby addressing the limitations of conventional workflows. A critical analysis of methodological gaps, such as inconsistent pressure–temperature conditions, oversimplified brine chemistry, and a lack of standardization, reveals experimental sources of scale translation errors and performance uncertainty. By comparing the unique challenges of depleted gas reservoirs (such as low water saturation and legacy well leakage) to those of saline aquifers (including pressure buildup and caprock integrity), this review identifies formation-specific priorities for experimental design. Novel contributions include a synthesis of best practices, integration strategies for model calibration, and recommendations for standardizing core handling, saturation procedures, and reporting protocols. Furthermore, this work serves as a guide for developing robust, field-relevant experimental strategies that can increase the deployment and regulatory acceptance of CO 2 storage technologies at scale.

58 GEOSCIENCES↗

NASA NTRSDate not supplied

Hematite Formation and Growth in Gale Crater Seen Through MSL Chemin X-Ray Diffraction Data

For more than 10 Earth years, the Mars Science Laboratory (MSL) Curiosity rover has been studying modern sediments and ancient sedimentary rocks deposited by lacustrine, fluvial, deltaic, and eolian processes in Gale crater. The mineral and X-ray amorphous abundances in rocks and sediments have been quantified via X-ray diffraction (XRD) data from the CheMin instrument. The received data demonstrate significant mineralogical variations within the stratigraphy, including changes in the type and abundances of Fe-oxides/oxyhydroxides silica polymorphs, phyllosilicates, and sulfate minerals. Characterizing Fe-oxides/oxyhydroxide minerals in Gale crater is especially important for constraining past aqueous environments because their formation depends on a variety of conditions, including pH, Eh, temperature, and salinity. Hematite, magnetite, goethite, and akaganeite have been identified by CheMin in different portions of the stratigraphic section. Hematite is the most prevalent Fe-bearing oxide mineral and has been detected (>1 wt.%) in 34 of the studied 36 drill targets. Variations in hematite crystallite size were reported in association with Vera Rubin ridge, which has a strong hematite signature in orbital reflectance spectroscopy. Here, we calculate hematite crystallite sizes and shapes for the entire stratigraphic section to date, to characterize trends and evaluate the processes by which hematite formed and transformed in Gale crater.

M. Szczerba↗

NASA NTRS1984

Possible Sea Ice Impacts on Oceanic Deep Convection

Many regions of the world ocean known or suspected to have deep convection are sea-ice covered for at least a portion of the annual cycle. As this suggests that sea ice might have some impact on generating or maintaining this phenomenon, several mechanisms by which sea ice could exert an influence are presented in the following paragraphs. Sea ice formation could be a direct causal factor in deep convection by providing the surface density increase necessary to initiate the convective overturning. As sea ice forms, either by ice accretion or by in situ ice formation in open water or in lead areas between ice floes, salt is rejected to the underlying water. This increases the water salinity, thereby increasing water density in the mixed layer under the ice. A sufficient increase in density will lead to mixing with deeper waters, and perhaps to deep convection or even bottom water formation. Observations are needed to establish whether this process is actually occurring; it is most likely in regions with extensive ice formation and a relatively unstable oceanic density structure.

Parkinson, C. L.↗

NASA NTRS1994

The effect of dDAVP with saline loading on fluid balance during LBNP and standing after 24-hr head-down bedrest

Shuttle astronauts currently drink approximately a quart of water with eight salt tablets before reentry to restore lost body fluid and thereby reduce the likelihood of cardiovascular instability and syncope during reentry and after landing. However, the saline loading countermeasure is not entirely effective in restoring orthostatic tolerance to preflight levels. We tested the hypothesis that the effectiveness of this countermeasure could be improved with the use of a vasopressin analog, 1-deamino-8-D-arginine vasopressin (dDAVP). The rationale for this approach is that reducing urine formation with exogenous vasopressin should increase the magnitude and duration of the vascular volume expansion produced by the saline load, and in so doing improve orthostatic tolerance during reentry and postflight.

NASA Discipline Number 14-10↗

NASA NTRS2001

Salt Marsh Formation in the Lower Hudson River Estuary

Salt marshes are constant depositional environments and as a result contain accurate indicators of past relative sea level rise and salinity. The Hudson River marshes are at least twice as deep when compared to coastal marshes on either side of the mouth of the Hudson. The reason for this difference in sedimentation is unclear. This study uses macrofossil data as well as sediment stratigraphy in order to understand the formation and evolution of these marshes. The composition of seeds, roots, shoots and foraminifera, are used to indicate past sea levels. The four sites involved in this study are, from south to north, the Arthur Kill Marsh in Staten Island (40 36 N, 74 77W), Piermont marsh (N 4100; 73 55W) Croton Point (41 14 N; 73 50W) and Iona Island (41 18N, 73 58W). These are all tidally influenced but with increasing distances from the New York Bight, which gives a good spectrum of tidal influence. AMS-C14 dates on basal macrofossils will document the time of each marsh formation. Basal material from Arthur Kill (8 m) includes freshwater seeds such as Viola, Potomageton and Alnus along with Salix buds. Basal material from Croton Point (10 m) includes fibrous woody material, foraminifera and Zanichellia seeds and other brackish vegetational components. The basal material from Piermont (13.77 m) is lacking any identifiable macrofossils between 150 and 500 microns. The basal material from Iona Island (10 m) has vegetation such as Scirpus and Cyperus seeds, probably implying a brackish environment. The freshwater origin of the Arthur Kill marsh in Staten Island is significant because it predates either sea level rise or the western channel incision. Additional implications for this study include evidence for changes in river channel geomorphology. Reasons for the relatively deeper river marshes include possible basal clay compaction, high production due to river and marine nutrients as well as tectonic activity. This study provides the groundwork for more high-resolution studies of these marshes to understand the fluctuations in salinity caused by relative sea level rise, tectonic faulting and/or changes in precipitation/evaporation.

Merley, Michael↗

NASA NTRS1995

Polarimetric scattering from layered media with multiple species of scatterers

Geophysical media are usually heterogeneous and contain multiple species of scatterers. In this paper a model is presented to calculate effective permittivities and polarimetric backscattering coefficients of multispecies-layered media. The same physical description is consistently used in the derivation of both permittivities and scattering coefficients. The strong permittivity fluctuation theory is extended to account for the multiple species of scatterers with a general ellipsoidal shape whose orientations are randomly distributed. Under the distorted Born approximation, polarimetric scattering coefficients are obtained. These calculations are applicable to the special cases of spheroidal and spherical scatterers. The model is used to study effects of scatterer shapes and multispecies mixtures on polarimetric signatures of heterogeneous media. The multispecies model accounts for moisture content in scattering media such as snowpack in an ice sheet. The results indicate a high sensitivity of backscatter to moisture with a stronger dependence for drier snow and ice grain size is important to the backscatter. For frost-covered saline ice, model results for bare ice are compared with measured data at C band and then the frost flower formation is simulated with a layer of fanlike ice crystals including brine infiltration over a rough interface. The results with the frost cover suggest a significant increase in scattering coefficients and a polarimetric signature closer to isotropic characteristics compared to the thin saline ice case.

Nghiem, S. V.↗