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Fence and trees

House and trees in winter.

Trees in winter with snow.

Winter wood landscape with house in background.

Woods in winter.

Characterization of active military ranges is critical to the sustainability of training lands for the United States Military. An important element in this characterization is the determination of explosives residues resulting from both live fire and disposal of dudded munitions on these ranges. The U.S. Army Cold Regions Research and Engineering Laboratory has developed a suite of tools for use in sampling for residues in both soils and snow. These tools are lightweight, rugged, and easy to clean. Through extensive field use, they have been optimized for ease of use and sample accuracy. This Technical Note describes these tools and their use in different environments., The original document contains color images.

This report discusses improvements to the National Center for Atmospheric Research (NCAR) artificial snow generation machine and the results of anti-icing fluid testing with the improved machine. The improvements include: (1) improved control of snowfall rate, (2) development of an integrated frosticator plate/snow mass measuring system, (3) automatic control and recording of the experiment, and (4) direct control of the frosticator plate temperature through an area heater controlled by an interface unit. This improved machine was used to conduct anti-icing fluid holdover time tests on several Type IV fluids. The results showed the typical inverse relationship between holdover time and snowfall rate. The results from the improved machine were compared to previous natural and artificial snow tests conducted by the University of Quebec at Chicoutimi and NCAR and showed good agreement in general. Tests with varying snowfall rates showed a factor of 1.5 to 2.0 longer holdover time for nonconstant snowfall rates. This result suggests that natural snow conditions are not as severe as the constant snowfall rate conditions tested in the laboratory. Causes for the longer holdover time were suggested to be: (1) the longer time available for the absorption of the melted snow water, and (2) the warmer temperatures experienced during the time varying rate tests as compared to the constant rate tests.

The overall mass balance of the Antarctic ice sheet has been estimated by comparison of the best available data on input in the form of snowfall with output in the form of ice flux through gates at or near the margin of the ice sheet. Surface melt is a negligible contributor to mass balance and has been ignored. Bottom melt under large ice shelves remains a major source of uncertainty. We conclude that there is probably an excess input of 2-25% of the total input, equivalent to a sea level lowering of 0.1-1.1 mm yr-l. Although errors remain, it becomes increasingly clear that an antarctic contribution to current sea level rise is unlikely. We attribute a reported iceberg flux that is larger than the mass input to a non-equilibrium breakback of the fronts of the ice shelves., This article is from 'Proceedings of the International Conference on the Role of the Polar Regions in Global Change Held in Fairbanks, Alaska on 11-15 June 990. Volume 2', AD-A253 028, p481-488. See also Volume 1, AD-A253 027.

Density, morphology, air permeability and liquid water content of snow were characterized and compared with measured deposition velocities to determine the relative importance of physical characteristics on the uptake of SO2 by snow. Highest deposition velocities (0.10 cm/sec) were associated with melting snow. Deposition velocities were higher for new snow (0.055 cm/sec) than for well metamorphosed snow (0.04 cm/sec). Fumigated snow was also used in melt experiments to evaluate the effects of solute distribution on the concentration of meltwater. Meltwater fractions were collected and analyzed for bisulfite, sulfate and nitrate. Both the melt rate and the distribution of the solute within the snowpack and within the snow grain influenced the elution pattern. Highest concentration effects were observed for bisulfite under conditions of slow melt. Concentrations of the initial meltwater were 2 to 4 times that of the bulk snow for sulfate and 2 to 9 times for bisulfite.

The accuracy of currently used long-term runoff forecasting techniques, such as used by the Soil Conservation Service, are limited because of their inability to deal with the uncertainty in the amount of precipitation expected to fall after the forecast date. The basis for a simulation-based, long-term runoff forecasting technique is developed to overcome this problem by simulating future precipitation events. The technique utilizes a deterministic watershed snowmelt model and a sequence, event-based stochastic precipitation model to provide daily precipitation data inputs for the watershed model. A number of sets of inputs are run through the watershed model to produce an equal number of predictions of total seasonal runoff. A relative frequency distribution of total seasonal runoff is then plotted to which a PDF may be fitted. Various criteria were used to test the precipitation model. The majority showed no significant differences between the observed and simulated data. The lack of data prevented reasonable watershed model optimization and testing. Taking into consideration the poor watershed model response the forecasting technique responded well to the uncertainty in future precipitation and to abnormal monthly precipitation.

Depth profiles of S(IV) and S(VI) in snow exposed to 20-140 ppbv SO₂ for 6 to 12 hours have been determined in 48 laboratory experiments. Surface deposition velocity (v(d)) averaged 0.06 cm s⁻¹. Well-metamorphosed snow, longer run times, higher SO₂ concentrations and colder snow were associated with lower values of v(d), and vice versa. Melting followed by draining increased v(d) greatly (0.14 cm s⁻¹. Any effect of ozone on SO₂ v(d) was undetectable. Most sulfur in the snow was as S(VI), even without added ozone, indicating the presence of other oxidants, especially in new snow. Four NO₂ deposition experiments (average v(d) = 0.007 cm s⁻¹), and one combined SO₂-NO₂ deposition experiment were conducted. Ozone, sunlight and SO₂ did not enhance NO₂ deposition; NO₂ and sunlight did not enhance SO₂ deposition. The deposition of SO₂ into a snowpack is modelled as an aqueous system, where the liquid water is considered to be present on snow grain surfaces. Gas transport into the snow, air-water partitioning, and aqueous-phase reactions are explicitly considered. Three oxidants (Fe- or Mn-catalyzed O₂, O₂, and H₂O₂) act to convert S(IV) to S(VI), acidify the film, and inhibit further S(IV) uptake. Model calculations illustrate the primary importance of liquid-water mass fraction (X(m)) and the secondary importance of oxidative reactions on SO₂ v(d) to snow. Model and experimental results are similar for assumed X(m) on the order of one percent. Experiments were also conducted on the incorporation of SO₂ into ice depositing from the vapor at -7 and -15°C. Remarkably, SO₂ is captured in deposited ice at concentrations comparable to Henry's Law equilibrium with water at 0°C. Ozone and HCHO appear to inhibit, not enhance, SO₂ capture. An aqueous-film model accounting for the capture of SO₂ by depositing ice was developed. S(IV) concentrations may be enhanced in the liquid-like layer on growing ice surfaces due to solute exclusion from the bulk ice and greatly-retarded diffusion

Rept. for Oct 57-Jun 59, on Nuclear Weapons Effects on Structures, Terrain, and Waterways.

A remote PPI with display of three intensity levels in shades of gray and compensation for range variations in scope illumination has been set up for the WR-66 radar. Camera attachments have been added to both radars. Design of the data processor has been completed. Printed circuits have been drawn and chasses have been built. A sensing unit for a continuously and automatically recording raindrop spectrometer has been built. Data taken in a number of storms show clearly that the WR-66 radar does not suffer from the limitations of attenuation, and low sensitivity and resolution which have been observed in the AN/CPS-9 and SCR-615-B radars. Applications and Analysis: Analysis of the mesoscale precipitation patterns in various types of storms and their relation to macroscale parameters is continuing. Coastal cyclones, some overland cyclones from the southwest, cold fronts and air mass storms have been analyzed. Results of a numerical analysis of snowflake aggregation are summarized. (Author)

The objective of a terrain analog technique is to enable the comparison of geographic areas on the basis of those aspects of the terrain which are most significant for military operations. The following basic techniques are described in this report: Prevalence of critical or restrictive values of selected terrain factors; Suitability for military activities; Landform classification; and Total range of values of selected terrain factors.

Techniques and equipment have been developed to process snow in place for use as a construction material for roads and runways. A test device to simulate aircraft wheel loadings is needed to determine bearing capacity of the compacted snow and to search out possible processing misses in the material so they can be repaired before landing aircraft. To satisfy this need, a 20-ton semi-trailer was modified to receive two interchangeable aircraft test wheels mounted under the deck. Any desired load up to 38,500 pounds is applied to the test wheel through a power-operated hydraulic system. Ballast placed on the deck of the trailer serves to resist uplift caused by the reaction of the test wheel on the snow. The two test wheels have tires with maximum inflation pressures of 95 and 135 psi. The load test trailer will be used to study bearing capacity of compacted-snow areas near McMurdo, Antarctica, during Deep Freeze 66. (Author)

COMMERCIALLY AVAILABLE, TOWED-TYPE CONSTRUCTION MIXERS WERE MODIFIED AS SNOW MIXERS FOR THE NAVY'S COLD-PROCESSING SNOW-COMPACTION TECHNIQUES. TWO SIZES OF SNOW MIXERS, ALONG WITH OTHER SPECIAL EQUIPMENT, MENT, WERE NECESSARY TO PRODUCE GOO-QUALITY COMPACTED SNOW. ONE SIZE, A MODEL 24 SNOW MIXER, HAD A 24-INCH-DIAMETER ROTOR, A MAXIMUM PERIPHERAL SPEED OF 4960 FEET PER MINUTE. THE OTHER SIZE, A MODEL 42 SNOW MIXER, HAD A 42-INCH-DIAMETER ROTOR, A MAXIMUM ROTOR SPEED OF 515 REVOLUTIONS PER MINUTE, AND A MAXIMUM PERIPHERAL SPEED OF 5665 FEET PER MINUTE. BOTH MODELS SATISFACTORILY MIXED AND BLENDED SNOW FOR DEPTH-PRCESSED, COMPACTED-SNOW MATS. THEY WERE ALSO USEFUL FOR PROCESSING NEW DEEP SNOWFALL AND HEAVY DRIFT ON COMPACTED MATS FOR MAINTAINING THE COMPACTED SURFACE. THE MODEL 24 MIXER CAN CONSTRUCT A MAT UP TO 16 INCHES THICK; THE MODEL 42 MIXER CAN CONSTRUCT A MAT UP TO 28 IN THICK. TMIXERS ARE EFFECTIVE AT SPEEDS OF 150 FEET PER MINUTE AND A SINGLE UNIT CAN COVER 1-1/4 ACRES PER HOUR UNDER FAVORABLE CONDITIONS

Photograph of a painting of mountains afther an early snowstorm.

Creek at the old fence west of Interoaks.

Moonlight in the front yard in winter.

Boats named Raubles and Wanderer in the woods in owner's yard in winter.

Early Spring at the big lot at the river bend.

Snow road through the woods at river forest west of interoaks.

Willows in early spring at the fence corner of a big lot.

Snow road thru the wood at the river forest west of Interoaks.