Abstract:Winter-forest processes affect global and local climates. The interception-sublimation fraction (F) of snowfall in forests is a substantial part of the winter water budget (up to 40%). Climate, weather-forecast and hydrological modellers incorporate increasingly realistic surface schemes into their models, and algorithms describing snow accumulation and snow-interception sublimation are now finding their way into these schemes. Spatially variable data for calibration and verification of wintertime dynamics therefore are needed for such modelling schemes. The value of F was determined from snow courses in open and forested areas in Hokkaido, Japan. The value of F was related to species and canopystructure measures such as closure, sky-view fraction (SVF ) and leaf-area index (LAI ). Forest structure was deduced from fish-eye photographs. The value of F showed a strong linear correlation to structure: F D 0Ð44 0Ð6 ð SVF for SVF < 0Ð72 and F D 0 for SVF > 0Ð72, and F D 0Ð11 LAI. These relationships seemed valid for evergreen conifers, larch trees, alder, birch and mixed deciduous stands. Forest snow accumulation S F could be estimated from snowfall in open fields S o and to LAI according to S F D S o (1 0Ð11 LAI ) as well as from SVF according to S F D S o (0Ð56 C 0Ð6 SVF) for SVF < 0Ð72. The value of S F was equal to S o for SVF values above 0Ð72. The value of sky-view fraction was correlated to the normalized difference snow index (NDSI ) using a Landsat-TM image for observation plots exceeding 1 ha. Variables F and S F were related to NDSI for these plots according to: F D 0Ð37NDSI C 0Ð29 and S F D S o 0Ð81 C 0Ð37NDSI . These relationships are somewhat hypothetical because plot-size limitation only allowed one sparse-forest observation of NDSI to be used. There is, therefore, a need to confirm these relationships with further studies.

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The Kristineberg mining area in the western part of the Paleoproterozoic Skellefte Ore District, northern Sweden, is well known for its base-metal and recent gold discoveries. A pilot 3D geologic model has been constructed on a crustal scale, covering an area of 30ϫ 30 km to depths of 10 km. Constrained 3D inverse and forward gravity modeling have been performed to confirm and refine previous modeling along seismic profiles using mainly 2.5D techniques. The 3D inverse gravity modeling was geared to generating isodensity surfaces that enclose regions within the model of anomalous density contrast. The 3D forward gravity modeling was conducted to include faulting and folding systems that are difficult to include in the inversion. The 3D geologic model supports many previous interpretations but also reveals new features of the regional geology that are important for future targeting of base-metal and gold deposits. The margins of a thick granite in the south dip steeply inward, suggesting the possibility of room to accommodate another large base-metal deposit if the granitic rocks are juxtaposed with volcanic rocks at depth. Gravity modeling also suggests the observed Bouguer gravity high within the western metasediments can be explained by a large mafic intrusion that has dioritic to tonalitic composition and no significant magnetic signature. Because mafic-ultramafic intrusions within metasediments can indicate gold, this interpretation suggests the western metasediments have a high gold potential.

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The snow-water equivalent of late-winter snowpack is of utmost importance for hydropower production in areas where a large proportion of the reservoir water emanates from snowmelt. Impulse radar can be used to estimate the snow-water equivalent of the snowpack and thus the expected snowmelt discharge. Impulse radar is now in operational use in some Scandinavian basins. With radar technology the radar wave propagation time in the snowpack is converted into snow-water equivalent with help of a parameter usually termed the a-value. Use of radar technology during late winter brings about risk for measurements on wet snow. The a-value for dry snow cannot be used directly for wet snow. We have found that a liquid-water content of 5% (by volume) reduces the a-value by approximately 20%. In this paper an equation, based on snow density and snow liquid water content, for calculation of wet-snow a-value is presented.