To confirm radio-echo layering due to changes in density variations and in specific conductivity in the amount of acid impurities, radio-echo sounding surveys with impulse radar technique were carried out. The continuous and strong internal layers of the snow covers were found to give good correlation with strong peaks of specific conductivity of melted samples from ice cores, rather than the differences in density fluctuations between depositional layers. Measured high conductivity due to acidity variations in ice cores may be correlated with recent volcanic eruptions in the northern hemisphere, and in the Scotia Arc and the South Sandwich Islands.

If rain falls on a new snowcover, a water saturated layer is often clearly formed in it. A snowcover with a saturated layer is sometimes unstable; the snowcover is folded and dimples appear on the snow surface. The mechanism of this instability is discussed theoretically. As a result, we find that a snowcover with a saturated layer can be unstable owing to lateral movement of water along a saturated layer and elastic deformation of the snow layer directly under it. Then the wavelength of the instability depends on the snow density; this result is consistent with field observations.

Sea ice thickness was profiled in investigating the internal structure of sea ice in August 1982 near Syowa Station, East Antarctica, by drilling and using an impulse radar system. In this connection, the anisotropic properties of sea ice were studied by rotating the radar antenna on the horizontal surface of ice around the vertical axis. Ice cores 155 cm long were drilled for analysis of their internal structure, which showed that a brine-soaked layer existed at the depth of 90 cm. This layer corresponded to an internal echo of very strong intensity at this depth that did not change during the rotation of the antenna. Meanwhile, a bottom echo gave maxima and minima approximately every 90 degrees of rotation of the antenna; this alternation is attributable to the structure of newly grown ice with the preferred c-axis Orientation. From these findings we consider that two types of sea ice covered the area near Syowa Station: one with a brine-soaked layer; the other without. Irregularities in shape of the bottom echo suggest that the sea ice plane was composed of accumulated small plates of sea ice.

The high-salinity surface layer of young sea ice was subjected to field and laboratory experiments. Artificial pools, in which young ice was formed, were opened within a fast-ice sheet in the Saroma lagoon, Hokkaido, in February of 1983 and 1984. The salinity of 1 mm thick surface layer of the young ice was observed as high as 42.4‰, which exceeds the seawater salinity of 31‰. The surface salinity increased with rising surface temperature. When a load was placed on the fast ice near the pool, seeped brine of salinity 72.5‰ was observed on the surface of the young ice; and when the load was removed, the brine disappeared. Meanwhile, brine permeabilities, both upward and downward, were measured in the laboratory, Both permeabilities decreased logarithmically with lowering surface temperature. A remarkable anisotropy was observed: the upward permeability was greater than downward, and the ratio of upward to downward premeability increased with lowering surface temperature from 5 at -3 °C to 33 at -5°C. Upward and downward permeabilities in ms-1 were respectively 1x10-4 and 2x10-5 at -3°C, 2x10-5 and 6x10-7 at -5°C, and at -10°C upward permeability was 3x10-7.

Characteristics of annual net accumulation were studied in time and space in Mizuho Plateau, Antarctica. Annual variation of net accumulation was obtained from 1914 to 1981 from the analysis of a 30 m core bored in a high accumulation zone. Power spectral analysis of the annual accumulations shows two predominant periodicities, one of 45 years, and the other of 18 years.

Inland, with small accumulation and strong temperature gradient at the surface, developments of depth hoar and the metamorphism of oxygen isotope composition (δ18O) profile of snow take place near the snow surface. From experimental results, the authors propose some models of the metamorphism of δ18O profile of snow with temperature gradient. These models can be divided into two groups: one where a cap, such as an ice crust, is present, and the other without.

Four methods of measuring strain and pressure in a snow cover on a slope are presented. The hole-mark method and short-span deformation gauge are used to measure the internal strains of snow, the long-span deformation gauge to measure the local extension/contraction of a snow cover, and snow pressure gauge to measure the pressure in a snow cover.

The horizontal velocity of a thick ice sheet is maximum at the surface and decreases with increasing depth. The horizontal velocity profile at a given location differs from another location depending upon the in situ stress and temperature conditions and the changing but distinctive physical and chemical character of the ice profile. The main property changes that influence the behavior of horizontal ice flow include chemical impurity concentration levels (both solid and dissolved components) and c-axis orientation. Shoji and Langway (1984) calculated the velocity profiles for both the Camp Century and Dye-3 Greeland location by taking into consideration possible enhancement factor variations over the profiles. This analysis was compared with the theoretical and experimental strain rate data obtained for laboratory ice at the same stress and temperature levels. This study indicated that the largest horizontal velocity component is the result of a highly enhanced shear deformation zone, a few hundred meters thick existing at the base of the ice sheet.

Using continuous microwave systems at fixed frequencies in the X- and R-band, surface depression of a snowpack was obtained from interference between the emitted wave, at normal incidence to the snowpack surface, and the reflected wave from the snow surface. The microwave system worked as a simple interferometer in air with respect to the snow surface. The values of the depression could be obtained from the numbers of cycles of the fluctuation and the wavelength of the microwave used.

Field experiments were carried out to investigate a change in salinity of the snow cover on sea ice and of the snow ice. Snow which covered thin sea ice was flooded with the brine that was pushed out onto the sea ice surface, resulting in a rise in salinity to more than 32‰, which was higher than that of sea water. On the day after the salination of the snow, the flooded snow was found to have been either frozen into snow ice or kept unfrozen. In either case the brine was excluded in turn from the flooded snow. As a result, the wet snow or snow ice had a salinity somewhat above 20‰. It is suggested that subsequently the wet snow keeps the salinity at more than 20‰, while the salinity of the snow ice decreases gradually with time.

Visibility in blowing snow was investigated by measurements of visibility using optical targets, light attenuation of parallel beam and snow concentration and mass flux of airborne snow particles.

Visibility is thought to be inversely proportional to extinction coefficient of light according to Koschmeider’s equation of visibility. However, visually observed values are not in accordance with those calculated from extinction coefficient of light when visibility is at a very low range. The extinction coefficient of light is proportional to the total cross section of airborne snow particles in a light path. The total cross section is also in proportion to concentration of airborne snow particles. There are many reported investigations of relation between visibility and snow concentration with widely differing results. The extinction coefficient of light varies with the shape and size of the particles, but cannot totally account for observed differences.

Transforming the snow concentration into mass flux of snow particles, a better relation between visibility and mass flux was found. These facts are explained in terms of the size of snow particles which are large enough to be seen. Visibility through visible particles is determined not only by the homogeneous attenuation of light discovered by Koschmeider, but also by the influence of visible particles themselves and their afterimage.

Patterns like brittle-stars, known as “radially-grown meltpatterns” are formed on the surface of ice from water gushing through a hole in thin snow-covered ice. This in turn melts the snow on the surface while extending outward along the water veins produced.

This study has successfully produced artificial meltpatterns and thus made possible the accurate clarification of the mechanics of formation. Incidentally, concentric circle meltpatterns were also found. Matters concerning artificial meltpattern simulation tests and the formation speed are also discussed in this paper.

A snow tunnel is often formed between the water surface of a small stream and the base of a snow cover in snowy areas. Observations made in northern Japan revealed that the amount of snow ablated at the ceiling of the snow tunnel ranged widely from 1.3 - 50 kg/m2d. This amount was calculated using heat transfer method; assuming that the ceiling was ablated only by the flux of heat from stream water, the amounts observed and calculated were found consistent.

Hydrological and meteorological observations of river runoff, precipitation and air temperature were conducted 27 August to 26 October 1982, in Langtang Valley, Nepal Himalaya, whereby the mass balance of the glacier system there was estimated. Observed values suggest that (1) all glacier ablation and rainwater in the subwatershed of Langtang Valley drain into the river with the runoff coefficient of 1; (2) ablation of the glacier system can be estimated simply using a degree-day factor of 10 mm/degree-day; and (3) precipitation is considered uniform over the whole watershed. Assuming that the suggested phenomena persist throughout the year, records of monthly precipitation and monthly mean temperature in this valley, indicate that annual accumulation and ablation in the glacier system amount to 2000 ± 200 mm, respectively.