Artificial Ice Research Articles

Frozen landscapes: climate-adaptive design interventions in Ladakh and Zanskar

During the course of the past three decades, a number of subsistence agricultural villages in the Himalayan mountain range have witnessed ever-shrinking glaciers and an increasingly erratic supply of glacial meltwater. Having relied on these relatively stable reserves for crop irrigation for centuries, today’s high-Himalayan farmers must now contend with irregular weather patterns and events, such as drought, mudslides and cloudbursts. In the face of this shifting landscape, many farming villages have responded by altering long-standing agricultural practices in an effort to adapt to a changing climate. In this context, the incorporation of frozen landscape infrastructures can help to control the flow of surface meltwater, direct valuable water resources and stockpile irrigation reserves in the form of ice and snow. This article describes three types of frozen landscape design interventions currently employed in northern India: artificial glaciers, ice stupas and snow barrier bands. Although these constructs have been designed by engineers rather than landscape architects, they contribute to a larger body of climate-adaptive design solutions that suggest a way forward in the face of the unstable environmental pressures of the future. As landscape architects and designers look for opportunities to intervene in the climate crisis, the nascent frozen landscapes of northern India present ideas for climate change adaptive design work to build upon.

Cross Validation Of A Figure Skating Blade Instrumented To Measure Figure Skating Impact Forces.

Competitive figure skating requires a vast amount of athleticism with an artistic touch. Skaters spend hours each day on-ice mastering jumps, spins, and footwork. The high workload may be related to overuse injuries, which are very common in figure skating, especially at the elite level. To better understand the relationships between on ice training and injuries, it is important to understand the loading patterns acting on skaters. PURPOSE: To validate an instrumented figure skating blade that is designed to measure impact forces while skating. METHODS: Seven subjects (Age: 21.3±2.8 yrs, Ht: 166.9±2.5 cm, Mass: 64.7±7.9 kg) performed 20 landings each onto artificial ice while landing on the instrumented blade from heights of 17.5cm, 25cm, and 33cm. A custom instrumented blade calibrated to measure in forces in Newtons (N) was used to measure impact forces (1000Hz) during landings. These forces were compared to forces obtained while subjects landed on AMTI force plates located underneath the artificial ice surface. Boot angle (250Hz) and force plate data (1000Hz) were collected using Vicon Nexus. Custom LabVIEW programs were used to determine peak force, loading rate, impulse, and the correlation between the blade force data and the force plate data. Paired T-tests were used to compare peak force, loading rate, and impulse between the blade and force plate data. Alpha = 0.05. RESULTS: Correlations between the blade force data and force plate data were good to excellent: mean r (±SD) = .86 ± 0.08. No significant differences were found for peak force and impulse between the blade and force plate data. Peak force means (±SD) were 1353.7 ± 352.2 N for the blade and 1361.2 ± 309.7 N for the force plate (p=.86). The means (±SD) for impulse were 44.99 ± 21.2 Ns for the blade and 48.1 ± 17.7 Ns for the force plate (p=.125). Loading rate, calculated from impact to time of peak force, was significantly higher (p = 0.0004) for the blade data (28.88 ± 22.8 N/ms) as compared to the force plate data (9.77 ± 7.5 N/ms). CONCLUSION: The custom instrumented blade is a valid tool for measuring peak forces and impulse during landings. Current research is focused on increasing the gain of the instrumented blade to improve loading rate accuracy. Supported by US Figure Skating, Sports Science and Medicine Grant 2011

Reconfigurable wave band structure of an artificial square ice

Artificial square spin ices are structures composed of magnetic elements arranged on a geometrically frustrated lattice and located on the sites of a two-dimensional square lattice, such that there are four interacting magnetic elements at each vertex. Using a semi-analytical approach, we show that square spin ices exhibit a rich spin wave band structure that is tunable both by external magnetic fields and the configuration of individual elements. Internal degrees of freedom can give rise to equilibrium states with bent magnetization at the edges leading to characteristic excitations; in the presence of magnetostatic interactions these form separate bands analogous to impurity bands in semiconductors. Full-scale micromagnetic simulations corroborate our semi-analytical approach. Our results show that artificial square spin ices can be viewed as reconfigurable and tunable magnonic crystals that can be used as metamaterials for spin-wave-based applications at the nanoscale.

Engineering of frustration in colloidal artificial ices realized on microfeatured grooved lattices.

Artificial spin ice systems, namely lattices of interacting single domain ferromagnetic islands, have been used to date as microscopic models of frustration induced by lattice topology, allowing for the direct visualization of spin arrangements and textures. However, the engineering of frustrated ice states in which individual spins can be manipulated in situ and the real-time observation of their collective dynamics remain both challenging tasks. Inspired by recent theoretical advances, here we realize a colloidal version of an artificial spin ice system using interacting polarizable particles confined to lattices of bistable gravitational traps. We show quantitatively that ice-selection rules emerge in this frustrated soft matter system by tuning the strength of the pair interactions between the microscopic units. Via independent control of particle positioning and dipolar coupling, we introduce monopole-like defects and strings and use loops with defined chirality as an elementary unit to store binary information.

Ice cover affects the growth of a stream-dwelling fish.

Protection provided by shelter is important for survival and affects the time and energy budgets of animals. It has been suggested that in fresh waters at high latitudes and altitudes, surface ice during winter functions as overhead cover for fish, reducing the predation risk from terrestrial piscivores. We simulated ice cover by suspending plastic sheeting over five 30-m-long stream sections in a boreal forest stream and examined its effects on the growth and habitat use of brown trout (Salmo trutta) during winter. Trout that spent the winter under the artificial ice cover grew more than those in the control (uncovered) sections. Moreover, tracking of trout tagged with passive integrated transponders showed that in the absence of the artificial ice cover, habitat use during the day was restricted to the stream edges, often under undercut banks, whereas under the simulated ice cover condition, trout used the entire width of the stream. These results indicate that the presence of surface ice cover may improve the energetic status and broaden habitat use of stream fish during winter. It is therefore likely that reductions in the duration and extent of ice cover due to climate change will alter time and energy budgets, with potentially negative effects on fish production.

Femtosecond laser cleaning the surface of reflective mirror in telescope

Metallic mirror is the core component of the imaging system in the reflective astronomical telescope. However, because the telescopesare usually located in the wild, they are often contaminated by dust and other pollutants which will greatly reduce the imaging quality. Therefore, the surface of reflective mirror in telescope should be cleaned routinely in order to recover high performance of telescope. Currently, the artificial ice cleaning is the most common method employed in the cleaning of mirror surface, which is complicated and costly. Besides, the micron particles adhered on the surface of the mirror are especially difficult to be removed by dry ice flow when their diameters are less than 20 μ m because of the Van der Waals force between the particles and metal mirror. Moreover, an ordinary method with wipe and cleanser is also used in which the friction between wipe and mirror may damage the telescope. To overcome these shortcomings, this work proposed a laser cleaning strategy in which amplified femtosecond pulsed lasers was used to clean the reflecting mirror surface. As a new cleaning method, laser cleaning technology which is non-contact and frictionless has been applied successfully in the cleaning of industrial molds, buildings, precision machinery components. For the advantages of femtosecond laser, such as short pulse duration, small thermal effects, high pulse energy, it has been used in the cleaning of cultural relics and has good achievement in recent years. This article firstly studied the interaction between the femtosecond laser and the reflective aluminum mirror. The laser damage threshold of aluminum mirror was measured about 60 mJ/cm2, which would reduce to 57 mJ/cm2 for dirty mirror because of the microparticles adhered on the surface of reflector mirror. Then, by optimizing laser parameters including the scan rate, the scan pitch, and the laser energy, it could be found that when the laser energy density ranges from 30 to 55 mJ/cm2, micron dust particles with diameters less than 20 μ m on mirror surface could be cleaned with excellent clean effect and the reflectivity in the visible light region has been greatly improved. Finally, through the dust particles and aluminum mirror substrate spectrum analysis, we ruled out that the removed microparticles were thermal melted by laser energy. The results indicated that thermal expansion plays the key role in laser cleaning of metal mirror. This work shows that femtosecond laser cleaning has a good effect on the removing of micron particles. As a simple and easy way, femtosecond laser cleaning has a good prospect in cleaning of astronomical telescope.

Modeling high-frequency acoustic backscatter for remote sensing of oil under sea ice and oil encapsulated in sea ice

High-frequency acoustic systems provide one of the potentially practical means for remote sensing of oil-in-ice. Sea ice is a complex medium that reflects, refracts, and scatters sound waves in complicated manner. The presence of oil adds additional complexity. A set of high-frequency acoustic data were taken at the Cold Regions Research and Environmental Laboratory (Hannover, NH) where crude oil was injected underneath artificial sea ice. A physics-based model is developed to interpret the data. The model consists of four layers to respectively describe the homogeneous half-space of water, the heterogeneous oil layer under ice, a thin skeletal ice layer, and a thick layer for the body of ice. The skeletal layer is allowed to have very different properties from the body of ice. All the interfaces at the boundaries of the layers are assumed rough. The model predicts scattered sound intensity in the time domain. Model results are discussed when it is applied to the acoustics data taken at both normal and 20-degree oblique incidence angles. The utility and the applicability of the model to actual arctic environments are anticipated.

Broken vertex symmetry and finite zero-point entropy in the artificial square ice ground state

We study degeneracy and entropy in the ground state of artificial square ice. In theoretical models, individual nanomagnets are typically treated as single spins with only two degrees of freedom, leading to a twofold degenerate ground state with intensive entropy and thus no zero-point entropy. Here, we show that the internal degrees of freedom of the nanostructures can result, through edge bending of the magnetization and breaking of local magnetic symmetry at the vertices, in a transition to a highly degenerate ground state with finite zero-point entropy, similar to that of the pyrochlore spin ices. We find that these additional degrees of freedom have observable consequences in the resonant spectrum of the lattice, and predict the occurrence of edge ``melting'' above a critical temperature at which the magnetic symmetry is restored.

Under-ice eddy covariance flux measurements of heat, salt, momentum, and dissolved oxygen in an artificial sea ice pool

Turbulent exchanges under sea ice play a controlling role in ice mass balance, ice drift, biogeochemistry, and mixed layer modification. In this study, we examined the potential to measure under-ice turbulent exchanges of heat, salt, momentum, and dissolved oxygen using eddy covariance in an experimental sea ice facility. Over a 15-day period in January 2013, an underwater eddy covariance system was deployed in a large (500m3) in-ground concrete pool, which was filled with artificial seawater and exposed to the ambient (−5 to −30°C) atmosphere. Turbulent exchanges were measured continuously as ice grew from 5 to 25cm thick. Heat, momentum, and dissolved oxygen fluxes were all successfully derived. Quantification of salt fluxes was unsuccessful due to noise in the conductivity sensor, a problem which appears to be resolved in a subsequent version of the instrument. Heat fluxes during initial ice growth were directed upward at 10 to 25Wm−2. Dissolved oxygen fluxes were directed downward at rates of 5 to 50mmolm−2 d−1 throughout the experiment, at times exceeding the expected amount of oxygen rejected with the brine during ice growth. Bubble formation and dissolution was identified as one possible cause of the high fluxes. Momentum fluxes showed interesting correlations with ice growth and melt but were generally higher than expected. We concluded that with the exception of the conductivity sensor, the eddy covariance system worked well, and that useful information about turbulent exchanges under thin ice can be obtained from an experimental sea ice facility of this size.

Photosynthetic and phenological responses of dwarf shrubs to the depth and properties of snow

Snow is known to have a major impact on vegetation in arctic ecosystems, but little is known about how snow affects plants in boreal forests, where the snowpack is uneven due to canopy impact. The responses of two dwarf shrubs, the evergreen Vaccinium vitis‐idaea and the deciduous V. myrtillus, to snow conditions were studied in a snow manipulation experiment in southern Finland. The thermal insulation of the snowpack was expected to decrease with partial removal or compression of the snow, while addition of snow was expected to have the opposite effect. The penetration of light was manipulated by partial removal of snow or by formation of an artificial ice layer in the snowpack. CO2 exchange measurements that were carried out at the time of maximum snow depth in late March indicated significant photosynthetic activity in the leaves of V. vitis‐idaea under snow. Net gain of CO2 was observed in the daytime on all the manipulation plots, excluding the snow addition plots, where light intensity was very low. The subnivean photosynthesis compensated for a substantial proportion (up to 80%) of the respiratory CO2 losses. Chlorophyll fluorescence measurements indicated reduced potential capacity of photosystem II in the leaves of V. vitis‐idaea on those plots where snow cover was thin. Neither V. vitis‐idaea nor V. myrtillus suffered from frost damage (assessed as electrolyte leakage) when thermal insulation was reduced by means of snow manipulations. No phenological responses were observed in V. vitis‐idaea, but in V. myrtillus bud burst, leaf unfolding and flowering were advanced by 1–3 days on the addition plots. The results of the present study show that dwarf shrubs respond to not only the thickness of snow but also the physical properties of snow, both of which are expected to change due to climatic warming.

A bobsleigh simulator software

This paper presents a model of the artificial ice track in Whistler, Canada that is based on its construction data, and a model of a two-men bobsleigh consisting of nine rigid bodies, having 13 degrees of freedom and incorporating 17 hard frictional contacts. These models are implemented within a simulator that is capable of performing accurate real time simulations of piloted runs on commonly available PC hardware. The simulation is verified against the results of the official two-men race that took place during the Olympic Winter Games in 2010. The simulator has been used by several professional Swiss pilots during their preparation for the 2014 Olympic Winter Games in Sochi, Russia. The simulator is exploited to analyse and judge the range of possible driving lines regarding speed and runtime improvements. It could also serve to consult track designers about safety issues and sleigh constructors about the expected dynamics on a track.

Microbial abundance in surface ice on the Greenland Ice Sheet.

Measuring microbial abundance in glacier ice and identifying its controls is essential for a better understanding and quantification of biogeochemical processes in glacial ecosystems. However, cell enumeration of glacier ice samples is challenging due to typically low cell numbers and the presence of interfering mineral particles. We quantified for the first time the abundance of microbial cells in surface ice from geographically distinct sites on the Greenland Ice Sheet (GrIS), using three enumeration methods: epifluorescence microscopy (EFM), flow cytometry (FCM), and quantitative polymerase chain reaction (qPCR). In addition, we reviewed published data on microbial abundance in glacier ice and tested the three methods on artificial ice samples of realistic cell (102–107 cells ml−1) and mineral particle (0.1–100 mg ml−1) concentrations, simulating a range of glacial ice types, from clean subsurface ice to surface ice to sediment-laden basal ice. We then used multivariate statistical analysis to identify factors responsible for the variation in microbial abundance on the ice sheet. EFM gave the most accurate and reproducible results of the tested methodologies, and was therefore selected as the most suitable technique for cell enumeration of ice containing dust. Cell numbers in surface ice samples, determined by EFM, ranged from ~ 2 × 103 to ~ 2 × 106 cells ml−1 while dust concentrations ranged from 0.01 to 2 mg ml−1. The lowest abundances were found in ice sampled from the accumulation area of the ice sheet and in samples affected by fresh snow; these samples may be considered as a reference point of the cell abundance of precipitants that are deposited on the ice sheet surface. Dust content was the most significant variable to explain the variation in the abundance data, which suggests a direct association between deposited dust particles and cells and/or by their provision of limited nutrients to microbial communities on the GrIS.

Development of Melting System for Measurement of Trace Elements and Ions in Ice Core

We present a titanium (Ti) melting head divided into three zones as an improved melting system for decontaminating ice‐core samples. This system was subjected to performance tests using short ice‐core samples (4 × 4 cm2, ~5 cm long). The procedural blanks (PBs) and detection limits of ionic species, with the exception of , were comparable with published values, but for elements the experimental procedures should be refined to obtain valid Zn concentrations due to the PB of ~90.0 ± 16.2 ng/L. The improved melting system efficiently decontaminated the samples, as verified by the concentration profiles of elements and ions in the melted samples from the three melting‐head zones. The recovery of trace elements in ice‐core samples was ~70–120% at ~100 ng/L in artificial ice cores. Because of the memory effects between ice‐core samples melted in series, the melting system should be rinsed at least 5–6 times (in a total volume of ~2.5 mL deionized water) after each melting procedure. Finally, as an application of this technique, trace elements were measured in ice‐core samples recovered from the East Rongbuk Glacier, Mount Everest, (28°03′N, 86°96′E, 6518 m a.s.l.), and the concentrations of trace elements following mechanical chiseling and the melting method were compared.

Use of RFID temperature monitoring to test and improve fish packing methods in styrofoam boxes

To fulfil the temperature requirements of the cold chain, the fresh fish are usually packed, stored and transported to fish markets with ice in open styrofoam boxes. Some companies offer a more flexible service and they deliver the fish directly to private consumers. In these cases the fish are packed with artificial ice – hydrated and frozen gel pads in specially designed completely closed styrofoam boxes. This study presents the results of the comparison of seven packing methods with the aim to potentially improve them. The temperature outside and inside of the closed box and temperatures in the abdominal cavity of gutted sea bass (Dicentrarchus labrax) were measured during the logistics process using Radio Frequency Identification (RFID) technology. The aim of the presented study is to define the optimal cooling materials and methods for different handling options. As an important result, a new efficient, time and energy saving method of packing the fish with the combination of dry non-hydrated gel pads and wet ice instead of the use of frozen gel pads alone is proposed. This method ensures recommended storage temperatures between 0°C and 4°C and stable conditions inside the box at room temperatures (or higher) for a longer period of time under the same time-ambient conditions after delivery to the consumer. Furthermore it was established that the part of the ice that melted inside the box, due to higher ambient temperatures, was absorbed by the dry gel pad and only a small quantity of water remained on the bottom of the box.

Determination of lead isotopes in a new Greenland deep ice core at the sub-picogram per gram level by thermal ionization mass spectrometry using an improved decontamination method

An improved decontamination method and ultraclean analytical procedures have been developed to minimize Pb contamination of processed glacial ice cores and to achieve reliable determination of Pb isotopes in North Greenland Eemian Ice Drilling (NEEM) deep ice core sections with concentrations at the sub-picogram per gram level. A PL-7 (Fuso Chemical) silica-gel activator has replaced the previously used colloidal silica activator produced by Merck and has been shown to provide sufficiently enhanced ion beam intensity for Pb isotope analysis for a few tens of picograms of Pb. Considering the quantities of Pb contained in the NEEM Greenland ice core and a sample weight of 10g used for the analysis, the blank contribution from the sample treatment was observed to be negligible. The decontamination and analysis of the artificial ice cores and selected NEEM Greenland ice core sections confirmed the cleanliness and effectiveness of the overall analytical process.

Parameterization of Centimeter-Scale Sea Ice Surface Roughness Using Terrestrial LiDAR

Microwave scattering from sea ice is partially controlled by the ice surface roughness. In this paper, we propose a technique for calculating 2-D centimeter-scale surface roughness parameters, including the rms height, correlation length, and form of autocorrelation function, from 3-D terrestrial light detection and ranging data. We demonstrate that a single scale of roughness can be extracted from complex sea ice surfaces, incorporating multiple scales of topography, after sophisticated 2-D detrending, and calculate roughness parameters for a wide range of artificial and natural sea ice surface types. The 2-D technique is shown to be considerably more precise than standard 1-D profiling techniques and can therefore characterize surface roughness as a stationary single-scale process, which a 1-D technique typically cannot do. Sea ice surfaces are generally found to have strongly anisotropic correlation lengths, indicating that microwave scattering models for sea ice should include surface spectra that vary as a function of the azimuthal angle of incident radiation. However, our results demonstrate that there is no fundamental relationship between the rms height and correlation length for sea ice surfaces if the sampling area is above a threshold minimum size.

Using of Ice for Constructing Islands in the Arctic Conditions

Artificial, grounded ice islands built by controlled flooding of the sea ice surface with sea water have been used for exploratory drilling in the Arctic offshore. Islands fabricated from ice are becoming more prevalent as offshore oil speculation in the Arctic gains more interest. Ice has been a strategic building material in the Arctic for the construction of roads, airstrips, housing, and, in the last few decades, as temporary drilling platforms to explore for oil. This article describes various methods of artificial ice building, the advantages and disadvantages of using man-made ice islands for exploratory drilling.

Physical and bacterial controls on inorganic nutrients and dissolved organic carbon during a sea ice growth and decay experiment

We investigated how physical incorporation, brine dynamics and bacterial activity regulate the distribution of inorganic nutrients and dissolved organic carbon (DOC) in artificial sea ice during a 19-day experiment that included periods of both ice growth and decay. The experiment was performed using two series of mesocosms: the first consisted of seawater and the second consisted of seawater enriched with humic-rich river water. We grew ice by freezing the water at an air temperature of −14°C for 14days after which ice decay was induced by increasing the air temperature to −1°C. Using the ice temperatures and bulk ice salinities, we derived the brine volume fractions, brine salinities and Rayleigh numbers. The temporal evolution of these physical parameters indicates that there was two main stages in the brine dynamics: bottom convection during ice growth, and brine stratification during ice decay. The major findings are: (1) the incorporation of dissolved compounds (nitrate, nitrite, ammonium, phosphate, silicate, and DOC) into the sea ice was not conservative (relative to salinity) during ice growth. Brine convection clearly influenced the incorporation of the dissolved compounds, since the non-conservative behavior of the dissolved compounds was particularly pronounced in the absence of brine convection. (2) Bacterial activity further regulated nutrient availability in the ice: ammonium and nitrite accumulated as a result of remineralization processes, although bacterial production was too low to induce major changes in DOC concentrations. (3) Different forms of DOC have different properties and hence incorporation efficiencies. In particular, the terrestrially-derived DOC from the river water was less efficiently incorporated into sea ice than the DOC in the seawater. Therefore the main factors regulating the distribution of the dissolved compounds within sea ice are clearly a complex interaction of brine dynamics, biological activity and in the case of dissolved organic matter, the physico-chemical properties of the dissolved constituents themselves.

Laboratory study on coprecipitation of phosphate with ikaite in sea ice

AbstractIkaite (CaCO3·6H2O) has recently been discovered in sea ice, providing first direct evidence of CaCO3 precipitation in sea ice. However, the impact of ikaite precipitation on phosphate (PO4) concentration has not been considered so far. Experiments were set up at pH from 8.5 to 10.0, salinities from 0 to 105, temperatures from −4°C to 0°C, and PO4 concentrations from 5 to 50 µmol kg−1 in artificial sea ice brine so as to understand how ikaite precipitation affects the PO4 concentration in sea ice under different conditions. Our results show that PO4 is coprecipitated with ikaite under all experimental conditions. The amount of PO4 removed by ikaite precipitation increases with increasing pH. Changes in salinity (S ≥ 35) as well as temperature have little impact on PO4 removal by ikaite precipitation. The initial PO4 concentration affects the PO4 coprecipitation. These findings may shed some light on the observed variability of PO4 concentration in sea ice.

Freezing and thawing of artificial ice by thermal switching of geometric frustration in magnetic flux lattices.

The problem of an ensemble of repulsive particles on a potential-energy landscape is common to many physical systems and has been studied in multiple artificial playgrounds. However, the latter usually involve fixed energy landscapes, thereby impeding in situ investigations of the particles' collective response to controlled changes in the landscape geometry. Here, we experimentally realize a system in which the geometry of the potential-energy landscape can be switched using temperature as the control knob. This realization is based on a high-temperature superconductor in which we engineer a nanoscale spatial modulation of the superconducting condensate. Depending on the temperature, the flux quanta induced by an applied magnetic field see either a geometrically frustrated energy landscape that favours an ice-like flux ordering, or an unfrustrated landscape that yields a periodic flux distribution. This effect is reflected in a dramatic change in the superconductor's magneto-transport. The thermal switching of the energy landscape geometry opens new opportunities for the study of ordering and reorganization in repulsive particle manifolds.