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Abstract: This paper describes an algorithm that has been developed to process field data from two upward looking sonars, one high (546kHz) and one low (235kHz) frequency, a 2MHz current profiler and a monitoring station, to measure surface ice characteristics on the North Saskatchewan River in the north east of Edmonton, AB, Canada, during the 2009/2010 freeze-up season. The algorithm used to calculate pans/rafts drafts and lengths, and the surface ice concentration is described. The validity and the accuracy of this technique were tested and computed surface ice conditions are presented. For the purpose of examining the effects of hydro-meteorological conditions on measured pan characteristics, the freeze-up period was divided into three distinct stages depending on the measured surface ice concentration. Pan/raft drafts were found to range from 0.1 to 1.0m and pan/raft lengths from 0.6 to 8.0m. The sonar proved to be very accurate in detecting the exact surface ice conditions locally above the sonar beam. However, interpretation of the results can sometimes be challenging, especially when physical processes such as bridging affect local ice conditions. Therefore, additional visual observations (e.g. time lapse photography) of surface ice conditions are recommended to aid in the interpretation of sonar measurements. [Copyright &y& Elsevier]

Abstract: The Balloon-borne Experiment with a Superconducting Spectrometer (BESS) was flown from Lynn Lake, Manitoba, Canada in August, 2000, during the maximum solar modulation period, with an average residual atmospheric overburden of 4.3g/cm2. Precise spectral measurements of cosmic ray hydrogen isotopes from 0.178GeV/n to 1.334GeV/n were made during the 28.7h of flight. This paper presents the measured energy spectra and their ratio, 2H/1H. The results are also compared with previous measurements and theoretical predictions. [Copyright &y& Elsevier]

Abstract: An extensive research project is currently being carried out at the University of Manitoba, Canada, involving the development of glass fiber-reinforced polymer (GFRP) wind turbine towers. The towers consist of multi-cell segments, each segment constructed from eight filament wound cells jointed together with resin applied over their interface. The present paper mainly addresses the static and dynamic characteristics, such as failure static loads, modes of failure, fundamental frequencies and periods of such segmented composite towers. Both experimental and numerical results are presented. The experimental investigation involved the testing of two jointed scaled towers. These specimens had a total height of 4.88-m (16-ft) and were tested as cantilevers under static and dynamic loading. The testing was conducted at the W.R. McQuade Structural Engineering Laboratory of the University of Manitoba. Finally, finite element models were developed to analyze the structural behavior, static and dynamic, of single and multi-cell composite segments and towers. The results from the finite element models under static loading were validated through comparison with the experimental results. [Copyright &y& Elsevier]

Abstract: Blowing snow is a frequent and significant winter weather event, and there is currently a need for more observations and measurements of blowing snow, especially in arctic and subarctic environments. This paper is the second part in a two part series studying blowing snow in Churchill, Manitoba, and Franklin Bay, NWT. In this part, the development and use of a camera system to measure the relative blowing snow density profile near the snow surface is described. This system has been used, along with standard meteorological instruments and optical particle counters, during a field campaign at Franklin Bay, NWT. A best-fit to the mass density profile in the saltation layer is derived, assuming a half-normal distribution of the vertical ejection velocity of saltating particles. Within the saltation layer, the observed vertical profile of mass density is found to be proportional to the function exp(− 0.61z/h̄), where h̄ is the average height of the saltating particles. For the range of conditions studied, h̄ varies from 1.0 to 10.4 mm, while the extent of the saltation layer varies from 17 to over 85 mm. There is a weak correlation between h̄ and the square of friction velocity. There are weak negative correlations between h̄ and temperature and relative humidity. No correlation is seen between h̄ and the snow age. At greater heights, z >0.2 m, the blowing snow density varies according to a power law (ρ s ∝z − γ), with a negative exponent 0.5<γ<3. Between these saltation and suspension regions, results suggest that the blowing snow density decreases following a power law with an exponent possibly as high as γ≈8. [Copyright &y& Elsevier]

Abstract: Blowing snow is a frequent and significant winter weather event, and there is currently a need for more observations and measurements of blowing snow, especially in arctic and subarctic environments. This is the first paper in a two part series studying blowing snow in Churchill, Manitoba, and Franklin Bay, NWT. In this part, the development and use of a camera system to measure the shape, size and velocity of blowing snow particles is described. This system was used, along with standard meteorological instruments and optical particle counters, during field campaigns at Churchill, MB, which took place in March, 2005 and December, 2006. Measurements of blowing snow particle shape demonstrate that blowing snow particles are generally non-spherical, with an average ratio of the longest particle profile length to the perpendicular width of 1.41. Measurement of particle velocity with the camera system is shown to be inaccurate. However, measurements of particle number correlate well (r 2 =0.85) with simultaneous measurements made with a particle counter at the same height as the camera. The particle size distributions generally follow a Gamma distribution, with an average shape parameter of α =1.9. The shape parameter, α, shows no trend with height. The blowing snow particle number density decreases with height as approximately N ∝ z −1.4. The blowing snow particle number densities, interpolated to a height of 0.1 m, are in the range of 1.4×105 < N <4.7×107 m−3. Particle number densities are shown to generally increase over a limited range of wind speeds, corresponding to 10-m wind speeds in the range of 13< U 10 <17 m s−1. Over this range of wind speeds, the average particle size at a given height does not change significantly with wind speed. However, at a lower wind speed of U 10 ≈9 m s−1, the average particle size is generally smaller. Particle sizes generally decrease with height between 0.06 and 1 m. Above 0.2 m, the average particle diameters found in this study (120 µm< d―<154 µm) are similar to or generally larger than the range of sizes found in previous studies. Below 0.15 m, the average particle diameters in this study (103 µm< d―<172 µm) are similar to or generally smaller than the sizes found in previous studies. There is a large variation in the mean particle sizes of this and other studies, suggesting that particle sizes may be dependent on a number of other factors, such as upwind snow conditions and surface characteristics. [Copyright &y& Elsevier]