Mm Of Ice Research Articles

Assessing the influence of simulated ice storm-induced crown damage on nonstructural carbohydrates, wound closure, and radial growth of maple trees

We evaluated shoot nonstructural carbohydrate (NSC) concentrations, stem wound closure, and radial growth of sugar maple ( Acer saccharum Marsh.) and red maple ( Acer rubrum L.) trees in a novel ice storm experiment in which five storm treatments (0, 6.4, 12.7, and 19.1 mm of radial ice accretion in 1 year and 12.7 mm of ice in two consecutive years) were applied within a mature northern hardwood forest. We tested for changes in physiology at two levels: (1) associated with plot-level ice treatments and (2) with crown damage classes of individual trees. Few differences in NSC or wound closure associated with treatment were found. Growth decreased for red maple in the medium and high treatments and sugar maple in the high treatment but no other treatments. Changes in physiology were more evident when assessed using crown damage classes. Two NSC components were elevated in sugar and red maples with high (≥50%) crown damage. Wound closure was less for red maples with high damage, and separation among damage classes was even greater for sugar maple. Red maples with moderate (<50%) and high crown damage showed gradually declining growth, whereas sugar maples with high damage showed ∼80% reduction in growth the first year after injury.

Self-heating ultra-high performance concrete with stainless steel wires for active deicing and snow-melting of transportation infrastructures

The development of self-heating concrete composites with stable electrical conductivity and strong heating capability as well as high mechanical properties is the key for achieving active deicing and snow-melting of transportation infrastructures. Due to their microscale diameter and high aspect ratio, stainless steel wires (SSWs) can form an extensive electrically and thermally conductive as well as reinforcing network inside concrete at a low content. Together with the stainless feature of SSWs as well as high structural compactness and durability of ultra-high performance concrete (UHPC), SSWs reinforced UHPC is expected to be developed into self-heating composites with strong and stable heating capability as well as ultra-high mechanical performance and durability. Therefore, this study evaluated the self-heating capability as well as active deicing and snow-melting performances of such composites. The developed SSWs reinforced UHPC slab demonstrates stable electrical conductivity and strong self-heating capability in cycle uses as well as efficient active deicing and snow-melting properties under different environmental conditions. The electrical resistivity of SSWs reinforced UHPC is only 2.58 Ω cm and it is hardly affected by the change in temperatures, numbers of cyclic self-heating, and numbers of deicing and snow-melting. The SSWs reinforced UHPC slab can be heated from 21.4 °C to 82.4 °C in 16.18 min under the voltages of 30 V in an indoor environment at a temperature of 21.2 °C. The slab only needs 28.98 min, 15.20 min, and 27.31 min to completely melt 9 mm of ice in a freezer at a temperature of −25.6 °C, 5 cm of naturally accumulated snow and 2 cm of artificially compacted snow in an outdoor environment at a temperature of about −5 °C with the wind speed up to 5.36 m s−1. Furthermore, thanks to their characteristics of no adverse effect on vehicle tires and excellent fatigue resistance, self-heating SSWs reinforced UHPC shows promising application prospects in active deicing and snow-melting of transportation infrastructures (e.g., airport runway, pavement and bridge deck) suffering from frigid weather.

Experimental approach and initial forest response to a simulated ice storm experiment in a northern hardwood forest.

Ice storms are a type of extreme winter weather event common to north temperate and boreal forests worldwide. Recent climate modelling studies suggest that these storms may become more frequent and severe under a changing climate. Compared to other types of storm events, relatively little is known about the direct and indirect impacts of these storms on forests, as naturally occurring ice storms are inherently difficult to study. Here we describe a novel experimental approach used to create a suite of ice storms in a mature hardwood forest in New Hampshire, USA. The experiment included five ice storm intensities (0, 6.4, 12.7 and 19.1 mm radial ice accretion) applied in a single year, and one ice storm intensity (12.7 mm) applied in two consecutive years. Results demonstrate the feasibility of this approach for creating experimental ice storms, quantify the increase in fine and coarse woody debris mass and nutrients transferred from the forest canopy to the soil under the different icing conditions, and show an increase in the damage to the forest canopy with increasing icing that evolves over time. In this forest, little damage occurred below 6.4 mm radial ice accretion, moderate damage occurred with up to 12.7 mm of accretion, and significant branch breakage and canopy damage occurred with 19.1 mm of ice. The icing in consecutive years demonstrated an interactive effect of ice storm frequency and severity such that some branches damaged in the first year of icing appeared to remain in the canopy and then fall to the ground in the second year of icing. These results have implications for National Weather Service ice storm warning levels, as they provide a quantitative assessment of ice-load related inputs of forest debris that will be useful to municipalities creating response plans for current and future ice storms.

On the icy edge at Louth and Korolev craters

The modern climate of Mars has been well characterized from over a decade of orbiting spacecraft, in situ measurements via landers/rovers, and theoretical advances in climate modeling. Nonetheless, important questions remain unanswered, including the present-day mass balance of the north polar residual cap and its icy outliers. Exposed water-ice mounds are found in craters, and extend as far equatorward as 70.2°N. Due to their southerly location, these ice mounds are likely more sensitive to ongoing changes in climate. We analyze high-resolution images of the Louth crater ice mound, and employ a coupled 1-D thermal and atmospheric model to estimate annual mass balance of both Louth and Korolev water ice. We incorporate the effects of shallowly-sloping surfaces and seasonally-dependent water ice albedo. No clear trend in the advance or retreat of Louth crater water ice is observed in over 4 Mars years of repeat, high-resolution images. Secular changes are either sufficiently small as to not be detected, or the ice is in equilibrium. Modeled mass balance ranges from −6 to +2 mm of water ice per Mars year at both sites, with nominal cases being in near-equilibrium (<0.5 mm of ice loss per Mars year).

A novel ice storm manipulation experiment in a northern hardwood forest

Ice storms are an important natural disturbance within forest ecosystems of the northeastern United States. Current models suggest that the frequency and severity of ice storms may increase in the coming decades in response to changes in climate. Because of the stochastic nature of ice storms and difficulties in predicting their occurrence, most past investigations of the ecological effects of ice storms across this region have been based on case studies following major storms. Here we report on a novel alternative approach where a glaze ice event was created experimentally under controlled conditions at the Hubbard Brook Experimental Forest, New Hampshire, USA. Water was sprayed over a northern hardwood forest canopy during February 2011, resulting in 7–12 mm radial ice thickness. Although this is below the minimum cutoff for ice storm warnings (13 mm of ice) issued by the US National Weather Service for the northeastern United States, this glaze ice treatment resulted in significant canopy damage, with 142 and 218 g C·m–2 of fine and coarse woody debris (respectively) deposited on the forest floor, a significant increase in leaf-on canopy openness, and increases in qualitative damage assessments following the treatment. This study demonstrates the feasibility of a relatively simple approach to simulating an ice storm and underscores the potency of this type of extreme event in shaping the future structure and function of northern hardwood forest ecosystems.

Nickel particle based electrical resistance heating cementitious composites

Abstract In this study, electrical resistance heating cementitious composites are developed by employing nickel particles as conductive fillers and heating elements. The conductive properties of cementitious composites with different types and different content levels of nickel particles are investigated. The electrical resistance heating performance of the composites is studied. Deicing and snow-melting experiments are also performed in refrigerator and outdoor environment, respectively. Experimental results show that the cementitious composites with nickel particles can achieve a temperature increment of about 50 °C within 30 s when the input voltage is 20 V. At an input voltage of 15 V, the cementitious composites with nickel particles (12.0 vol.% and 2.6–3.3 μm diameter) can deice 3 mm of ice in 478 s under an ambient temperature of − 16.0 °C and melt 2 cm of snow in 368 s under an ambient temperature of − 5.3 °C, respectively. These findings indicate that the fabricated cementitious composites with nickel particles have a superior electrical resistance heating performance.

Simulations of a comet impact on the Moon and associated ice deposition in polar cold traps

Modeling results of the water vapor plume produced by a comet impact on the Moon and of the resulting water ice deposits in the lunar cold traps are presented. The water vapor plume is simulated near the point of impact by the SOVA hydrocode and in the far field by the Direct Simulation Monte Carlo (DSMC) method using as input the SOVA hydrocode solution at a fixed hemispherical interface. The SOVA hydrocode models the physics of the impact event such as the surface deformation and material phase changes during the impact. The further transport and retention processes, including gravity, photodestruction processes, and variable surface temperature with local polar cold traps, are modeled by the DSMC method for months after impact. In order to follow the water from the near field of the impact to the full planetary induced atmosphere, the 3D parallel DSMC code used a collision limiting scheme and an unsteady multi-domain approach. 3D results for the 45° oblique impact of a 2 km in diameter comet on the surface of the Moon at 30 km/s are presented. Most of the cometary water is lost due to escape just after impact and only ∼3% of the cometary water is initially retained on the Moon. Early downrange focusing of the water vapor plume is observed but the later material that is moving more slowly takes on a more symmetric shape with time. Several locations for the point of impact were investigated and final retention rates of ∼0.1% of the comet mass were observed. Based on the surface area of the cold traps used in the present simulations, ∼1 mm of ice would have accumulated in the cold traps after such an impact. Estimates for the total mass of water accumulated in the polar cold traps over 1 byr are consistent with recent observations.

Modelling and Mapping Damage to Forests from an Ice Storm Using Remote Sensing and Environmental Data

An extreme ice storm in January 1998 deposited up to 100 mm of ice and resulted in significant forest damage across eastern North America. Average crown loss of over 75% was recorded in large areas of eastern Ontario and southern Quebec. A primary question that arose following the storm was: can forest damage be effectively assessed using remote sensing and other available environmental data? This paper presents two contrasting studies to address this question. The first involves damage modelling at a local scale in an unmanaged forest using spectral and spatial information in high-resolution airborne imagery. Results of field data analyses are also given that show relations between damage and forest structure and composition as well as changes in forest structure that occurred in the years following the storm. The second study involves regional scale damage mapping in managed and unmanaged forests of eastern Ontario using medium resolution satellite imagery and other environmental data. In comparison of several image classification and data interpolation methods, the best damage map was produced using a neural network classifier and a mix of Landsat and environmental data. The methods and results presented in this paper form the basis for ongoing long-term temporal study of damage impacts on forest condition.

Numerical simulation of water solidification phenomenon for ice-on-coil thermal energy storage application

The increasing demand for higher energy efficiency in existing power generation facilities requires implementation of demand-side management strategies, such as valley filling and load shifting. As an operational strategy, thermal energy storage (TES) is considered as an effective means for shifting electric loads from on-peak to off-peak hours. For manufacturing storage tanks and design of systems, prediction of the time required for water solidification and accumulation of ice by numerical simulation and experimental methods is necessary. The objective of this study is to develop a numerical simulation model and determine the amount of time needed for solidification of water around a circular cross-section TES coil. To meet the objective, transient heat and mass transfer analysis of the water solidification phenomenon around a circular pipe with boundary and initial conditions similar to those found in ice TES systems is required. An extensive literature survey is made, and utilizing a finite difference algorithm suggested by Du-Fort Frankle, the cylindrical coordinate system based numerical model is developed and the time duration for solidification of 10 mm of ice around a 20 mm diameter pipe is found to be 2609.4 s.

The relationship between ice thickness and northern hardwood tree damage during ice storms

The response of four tree species, Acer saccharum Marsh., Acer rubrum L., Populus tremuloides Michx., and Betula populifolia Marsh., to ice storm damage was studied in the northern hardwood forest of southern Quebec. The focus of the study was the impact of ice accretion on trees as a function of damage type and species at the stand and regional scales along a gradient of ice accumulation ranging from 2 to 88 mm radial thickness and to assess the role of the combined effect of ice and wind stress. Further, we estimate the return time for death resulting from ice storms in these forests. The study showed that the magnitude of ice accumulation was the primary determinant of tree damage (measured as the mean percentage of individual tree canopy removed) and that tree size was the primary determinant of damage type (bending, snapping, or substantial branch loss). Stand position (edge versus interior) did not influence susceptibility to damage. The research demonstrated that edge and slope trees bent or snapped in the direction dictated by crown asymmetry. We have no evidence that the modest winds during this icing event played a major role. Lastly, we couple the return time for a given ice thickness with the probability of severe damage to argue that (i) canopy tree mortality from icing is primarily due to glaze accumulations of moderate rarity (around 12–35 mm of ice) rather than extraordinary events such as 1998 and (ii) ice storms are likely the greatest single source of canopy tree mortality in the hardwood forests of southern Quebec with an estimated return time for death of about 250 years.

Energy Balance at the Surface of the Ice Sheet in the Coastal Area of Adélie Land, Antarctica (Abstract only)

Hourly measurements of wind, temperature, and humidity were made between elevations of 1 and 20 m in the coastal area of Adélie Land over a period of 45 d in January and February 1978. About 1000 profiles are available.The height of the constant flux layer is &gt;5 m despite the influence of katabatic winds, the wind profile is logarithmic with a mean standard deviation from the logarithmic law of 15 mm s−1. The potential temperature profile is also logarithmic with a mean standard deviation of 0.04°C. The most important deviation from the logarithmic law appears between -4 and 0°C.Humidity was measured at two points only, between 1 and 20 m; the mean gradient was about 0.01 mbar m−1 and the flux of latent heat was generally negligible.Net radiation was measured for only 10 d because of radiometer failure. All the fluxes are calculated using data for the 5 m layer. For the 10 d period, the heat loss was about 3 Wm−2 with a mean heat flux of -27.5 Wm−2 and mean net radiation of -10.5 Wm−2(the minus sign signifying the flux is towards the surface). In general, the heat flux is towards the surface (92% of the cases) but is away from the surface in the afternoon. The ablation during the 10 d period without snow-fall was about 200 mm of ice.

Energy Balance at the Surface of the Ice Sheet in the Coastal Area of Adélie Land, Antarctica (Abstract only)

Hourly measurements of wind, temperature, and humidity were made between elevations of 1 and 20 m in the coastal area of Adélie Land over a period of 45 d in January and February 1978. About 1000 profiles are available. The height of the constant flux layer is &amp;gt;5 m despite the influence of katabatic winds, the wind profile is logarithmic with a mean standard deviation from the logarithmic law of 15 mm s−1. The potential temperature profile is also logarithmic with a mean standard deviation of 0.04°C. The most important deviation from the logarithmic law appears between -4 and 0°C. Humidity was measured at two points only, between 1 and 20 m; the mean gradient was about 0.01 mbar m−1 and the flux of latent heat was generally negligible. Net radiation was measured for only 10 d because of radiometer failure. All the fluxes are calculated using data for the 5 m layer. For the 10 d period, the heat loss was about 3 Wm−2 with a mean heat flux of -27.5 Wm−2 and mean net radiation of -10.5 Wm−2(the minus sign signifying the flux is towards the surface). In general, the heat flux is towards the surface (92% of the cases) but is away from the surface in the afternoon. The ablation during the 10 d period without snow-fall was about 200 mm of ice.

Some aspects of the ice topography of Trough Lake, southern Victoria Land, Antarctica (Note)

Abstract Trough Lake has a permanent cover of floating ice. Contact of the ice with the Koettlitz Glacier produces pressure ridges which are modified by differential ablation. The estimated ablation rate of 300–450 mm of ice per year is higher than that at Lake Miers, 20 km north, due to the increased prevalence of katabatic winds at Trough Lake.