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This paper investigates the networked evolutionary model based on snow-drift game with the strategy of rewards and penalty. Firstly, by using the semi-tensor product of matrices approach, the mathematical model of the networked evolutionary game is built. Secondly, combined with the matrix expression of logic, the mathematical model is expressed as a dynamic logical system and next converted into its evolutionary dynamic algebraic form. Thirdly, the dynamic evolution process is analyzed and the final level of cooperation is discussed. Finally, the effects of the changes in the rewarding and penalty factors on the level of cooperation in the model are studied separately, and the conclusions are verified by examples.

The relationships in ASCE 7 for the determination of roof snow drift size are functions of the ground snow load and the upwind fetch of the snow source area. In a 2019 paper, O’Rourke and C...

A new taller building adjacent to an existing building with a lower roof is a relatively common situation. The new building provides a snow source area, which results in snow drift atop the lower roof which likely was not anticipated in its original design. Since it is usually difficult to retrofit the existing roof structure, a solid wall can be considered to capture the expected snow transport on the upper roof. Using field measurement on snowdrift development around solid walls, ASCE 7 provisions and Drift Ratio parameter, two approaches based on average or conservative values are studied to determine the required height of the solid wall. The results indicate that conservative values provide arguably unrealistic values, while the average or combination of average and conservative values provides reasonable wall heights.

Thirty-six apple cultivars representing Malus × domestica Borkh. were evaluated for diversity in fruit quality. Colour traits ‘L’, ‘b’ and ‘Tint’ were positively correlated with TSS and fruit size. ‘a’ values showed negative correlation with TSS but was positively correlated with fruit firmness. ‘L’ values ranged from 32.66 (Well Spur) to 76.48 (Supermore Gold). Negative ‘a’ value was observed for Orange Val (−5.17), Snow Drift (−1.67) and Greensleeves (−7.70) indicating that these cultivars are green in colour at the time of harvesting. The ‘b’ values ranged from 6.86 (King Hacious) to 52.18 (Supermore Gold) indicating that these cultivars are yellow in colour and none blue. Positive ‘Tint’ value (2.36) was observed in Greensleeves cultivar and rest of the cultivars showed negative value. Fruit firmness ranged from 26.00 (Starkrimson Gold) to 90.85 RI (Top Red) and TSS from 11.80 °B (Razakwari) to 20.03 °B (Salvapobedetalian). Principal component analysis showed that first three components with Eigen values were able to explain more than 78% of total variation. PC1, PC2 and PC3 accounted for 37, 28 and 13% respectively, of the trait variability. Cluster analysis distinguished all the cultivars into five distinct groups/clusters and one cultivar Starkrimson Gold does not form the part of any cluster. Cluster analysis also revealed the importance of fruit weight and fruit firmness for grouping of apple cultivars while as TSS was found to have no significant role in grouping. The PCA and clustering analysis in this study indicated a high level of diversity in the apple cultivars. The present study is useful for identifying the apple cultivars with desirable fruit quality traits useful for commercialization and crop improvement through breeding.

We present climate data, direct surface mass balance (SMB) observations and model results for Mocho Glacier in the Chilean Lake District. Mean annual temperature on a nunatak of Mocho Glacier at an elevation of ~2000 m was +2.6°C in 2006–15 and mean annual precipitation in Puerto Fuy (13 km from the glacier, at an elevation of 600 m) was 4000 mm for the same period. High interannual variations in the SMB of Mocho Glacier were observed. A simple SMB model is able to reproduce the observed annual variations in SMB, but fails to predict the steep observed mass-balance gradient. The average of the measured annual glacier mass balances in the four hydrological years 2009/10–2012/13 was −0.90 m w.e. a−1and the average modelled annual glacier mass balance 2006/07–2014/15 was −1.05 m w.e. a−1. The observed distributed ablation shows a clear altitudinal dependency, while accumulation is determined by patterns of snow drift as well. These patterns are only poorly represented in the model and have to be included in order to be able to reproduce a realistic SMB map of the glacier.

A methodology for performing a snow drift transport analysis is provided that considers the demonstrated dependency of snow transport on approximately the fourth power of wind speed, giving...

Drift loads on roofs are arguably the most important snow load from a structural engineering perspective in the US, as they are the governing load for most cases of snow related structural ...

New ultra-long transnational railway megaprojects are currently being planned or under construction. Along their route, they increasingly cross arid and desert regions. In these regions, railways are vulnerable to windblown sand. Several failure cases recently occurred, e.g. along the Linhai-Ceke railway in China, or the Aus-Luderitz railway in Namibia. We consider windblown sand as an environmental key factor, analogously to wind or snow drift. We categorize its effects into Sand Ultimate Limit States and Sand Serviceability Limit States. In the design perspective, the quantitative prediction of the windblown sand sedimented along the railway is mandatory. We propose a probabilistic approach to sedimented windblown sand modelling because of the inborn variability of the phenomenon. The proposed method allows evaluating the design value of the accumulated windblown sand volume for a given site.

This chapter provides a fairly consistent picture of the unlimited range of actions and effects induced by the wind on the environment and territory. Accordingly, it describes the transition from ancient windmills to modern wind turbines. It deals with the role of the wind in the transport and diffusion of minute materials, highlighting three issues: the diffusion of pollutants introduced in the air during combustion processes, soil erosion, a phenomenon able of changing the geomorphological features of nature and of making soil dry up with devastating consequences, and the snow drift that causes severe problems for road and rail traffic as well as for built areas. The chapter also deals with natural and artificial barriers and their manifold uses, first of all, the protection of crops. Finally, it continues the description of the efforts mankind carried out since ancient times to build settlements and dwellings taking inspiration from bioclimatic principles; in this framework, city planning and architecture came into contact with environmental and climatic issues reassessed on scientific grounds.

Windward snow drifts are an important consideration for many roof geometrics, including roof steps, parapet walls, and various roof projections. Current code provisions for windward roof sn...

Cooperation is often considered as one of the key and unclear concepts, which differentiates multi-agent systems from other related fields such as distributed computing. One of the popular benchmarks for the verification of the effectiveness of various cooperation algorithms is multi-agent foraging task. Different approaches have been proposed among which Markov game based ones are widely used, though they could not select consistent equilibrium for the group. In this paper, an evolutionary game based method is proposed. In this method, the interactions among the agents are modeled by snow-drift game to evolve the evolutionary stable strategy (ESS) and bring the maximal reward for the group of agents. The simulation verified the efficiency of the proposed algorithm.

International audience; Wind and the associated snow drift are dominating factors determining the snow distribution and accumulation in alpine areas, resulting in a high spatial variability of snow depth that is difficult to evaluate and quantify. The terrain-based parameter Sx characterizes the degree of shelter or exposure of a grid point provided by the upwind terrain without the computational complexity of numerical wind field models. The parameter has shown to qualitatively predict snow redistribution with good reproduction of spatial patterns, but has failed to quantitatively describe the snow redistribution. By comparing the parameter with high-resolution snow surface data obtained through terrestrial laser scanning (TLS), we are able a) to identify areas of poor correlations between predicted and measured snow distribution and changes in snow depths, and b) to increase its ability to predict changes in snow depths by modifying the parameter, based on the TLS data and the terrain and wind conditions specific to our research site, the Col du Lac Blanc in the French Alps. We show how results improve if a snow surface model is used for calculating the parameter instead of a digital elevation model, and demonstrate the effects of changing the parameter's maximum search distance and of raster smoothing. Our analyses and results are important steps in the improvements of the parameter's ability to predict changes in snow depths.

As baseball gets more and more popular the interest of fans increases. Since baseball game in its nature is influenced very much by weather the necessity of a domed stadium has been raised. At this moment a membrane structured domed stadium is under construction. As can be understood from the roof collapse of Minnesota Metrom by a heavy snowfall in 2011, the snow load occupies a very important part in membrane structure. To calculate the snow load snowdrift prediction is necessary and snow is piled mainly at the side or roof of a building. Hence, in this study a snowdrift wind tunnel test of a domed stadium was made to simulate snowdrift; using it the maximum depth of fresh snowdrift is estimated to be in the range of 3.4cm-37cm on the roof of a domed stadium.

The blizzard phenomenon is the climate risk that has the greatest impact on the road-ways in the South-Eastern part of Romania. The E85 section between Urziceni and Buzau has a great vulnerability to blizzard. Its vulnerability was proved during the 26 of January – the 14 of February 2012, when the road-way was blocked for 10 days. In order to establish the vulnerability level for E85 road, the section between Urziceni and Buzau, the Roads Vulnerability to Blizzard Index (RVBI) has been calculated and spatially modelled by using the GIS techniques. This index integrates several factors, such as: road sections orientation, buildings density in the vicinity of the road, width of the villages that are crossed by E85, the snow drift potential, within built-up areaʼs orientation to E85, the negative relief forms along the road section. The calculation of the RVBI points out that 74% of total length of the road present high and very high vulnerability during blizzard phenomenon. The road sections with high and very high vulnerability need protective measures, such as: forest belts plantation, using bigger snow fences, increasing the snow fences density and achieving more equipment for snow moving off by the local authorities.

Blowing and drifting snow continues to be a transportation and safety hazard with significant economic costs. Critical design criteria for the construction of a living (vegetated) snow fence are reviewed and presented using the most currently available design equations. Coupled with an analysis of climate and topographical data, the design criteria are applied to an area in Rocky Mountain National Park historically prone to snow drifting. The long-term average snow accumulation season (period beginning with the first blowing snow and ending with maximum drift density) was calculated from air temperature as between 4 November and 10 April, and these dates compared well with those based on nearby snow observations. Over the snow accumulation season, the potential for snow transport based on wind characteristics was 21.4 tonnes m−1 (all wind directions), of which 21.0 tonnes m−1 occurred along a mean drifting direction of 259° (nearly perpendicular to the road at the study site). The potential for s...

For about ten years, Meteo-France has developed and operated a real time operational suite aimed at snowpack simulation and avalanche risk forecasting: the numerical model chain Safran-Crocus-Mepra (SCM). It presently includes only a crude formulation of snowdrift effects at large spatial scales (massif). This paper presents the improvements to a snow drift module suited to the SCM chain. The new version, called SYTRON3 which aims at an improved simulation of snow drift effects at smaller spatial scales. It is coupled with the SCM environment, which provides hourly meteorological conditions and snow forcing. The main modifications concern the new parameterisation schemes, which are more realistic and more physically based. The increased number of vertical layers allows now to represent explicitly the three modes of movement during snow drift: creep, saltation and diffusion. The validation of this new version as well as comparisons with the previous version are performed at the Col du Lac Blanc test site (2700 m a.s.l., French Alps) by the use of digital photographs and field observations. D 2005 Elsevier B.V. All rights reserved.

An analytical procedure for simulating roof snow drift loads is presented. The procedure is based upon the physics of drift formation and consists of two elements. The first element is the transport rate which quantifies the snow flux from the snow source area. The second element is the trapping efficiency which quantifies the percentage of transported snow from the source area which is captured at the drift. Knowing wind speed and snowfall information for a given winter, the procedure can be used to simulate the annual maximum drift for a given snow source area. The method is applied to over 40 years of weather data at each of over 50 NWS first-order sites across the United States. The calculated annual maxima are fit with an extreme value distribution to determine 50-year drift loads for both roof step and gable roof geometries. It is shown that current leeward roof step drift provisions in ASCE 7-02 as well as gable roof drift provisions proposed for ASCE 7-05 yield loads with something close to a 50 year mean recurrence interval.

Formed metal deck roofs play an important role in steel building construction. There are many design variables in deck design to make it important for designers to put the right combination together to achieve a better design. In this paper, a procedure for the design of steel roofs subjected to non-uniform loads such as drifted snow is presented. The presented approach uses genetic algorithms to achieve optimal or near-optimal designs. The advantages of the model stem from two main points: (1) it searches for the optimum or near-optimum number of purlins for the roof; and (2) it determines the near-optimum spacing between purlins to minimize the structure weight. Details of model development are described and example applications are presented to demonstrate the model capabilities.

Three acoustic FlowCapt™ (IAV Engineering) drifting snow instruments were deployed during the 1999 and 2000 field season on Spitsbergen, Norway. Three different experiments were carried out to test the instruments for their use in snowdrift research. The data from the three instruments were compared during a study of drifting snow within an Arctic catchment and around a building. The principle of the instruments is based on the acoustic signal, generated by the mechanical impact of drifting snow particles on a vertical tube. Microphones inside the tube transmit the signal to a frequency analyser. By Fourier transformation, the signal can be divided into the high frequencies of the impacting snow particles and the low frequencies, resulting from the loosening wake eddies behind the tube. In this way, both snow drift flux and wind speed can be measured simultaneously. Results from the three experiments show that the instruments are useful tools to study drifting snow in remote areas. A reliable indication of the occurrence and strength of drifting snow events can be determined even if the absolute accuracy is difficult to quantify.

This paper uses a Geographical Information System (GIS) to develop a rule-based model of the effect of snow drifting on glacier growth in the Cairngorm Mountains, Scotland during the Younger Dryas interval. We develop a qualitative model of snow drift that uses a number of simple heuristics to generate a map of relative accumulation at a 50-m resolution over the massif. Relative susceptibility to snow drifting is then compared for a number of different zones under varying wind directions. We conclude that, under the conditions tested in our model, glaciation of the Cairngorms during the Younger Dryas was confined to the high corries and that the pattern of snow drifting suggested by our model points to dominant southerly winds. Copyright © 1999 John Wiley & Sons, Ltd.

数値モデルを用いて地吹雪の流動解析を行い,風洞での実験装置を用いた実験結果との比較を行った.数値モデルは,密度変化を全ての項で考慮した非ブーシネスクk-e乱流モデルであり,空気の連続式,雪粒子の質量保存則,レイノルズ方程式と乱れ運動エネルギー,分子粘性逸散率の式で構成される.この方程式系の性質を確かめるため,斜面の傾斜角,底面近傍の雪粒子濃度,雪粒子の粒径を変化させ計算を行った.低温風洞装置で吹雪を発生させ,熱膜流速計とSPCを用いて風速分布と吹雪量の鉛直方向の分布を測定した.その結果を数値モデルの結果と比較した.この結果,底面の粗度,底面近傍の濃度などの諸量について合理的な値を与えれば数値モデルと実験値との一致が良いことが分かった.

An investigation of unbalanced or drifted snow loading on single gable roofs is presented. A database of 28 case histories was developed and analyzed to identify trends and key parameters for this type of roof snow drift. The analysis suggests that roof slope, roof width (i.e., ridge to eave distance), and ground snow load are the key parameters influencing drift size. Furthermore, substantial drifts near the eaves of low sloped roofs (slope less than 15°) are possible, particularly if the width is large and the ground snow load is moderate. A number of simple relations were developed that can be used to predict the total height for low sloped roofs. Predicted values from these relations were compared with observed values to gauge their relative accuracy. It is felt that the simple relations developed herein are an improvement over current code provisions, specifically for low sloped gable roofs. It is expected that they will be the basis for proposed changes in building codes and load standards. The impl...

Current hypotheses on conifer tree stem degradation at treeline indicate the influence of frost desiccation caused by dehydration of wind-exposed needles above the snowpack because of frozen soil or wind abrasion. Here, we examine, in an exploratory study, the potential of detailed stem analysis to identify other causal factors at a subarctic treeline site using black spruce (Picea mariana (Mill.) BSP.) trees distributed along a wind-exposure gradient and showing various degrees of stem damage, from the normal, conical growth form to the mat growth form. Temporal patterns of stem development revealed a relatively integrated growth system within the tree as long as the normal arborescent form was maintained. With the gradual loss of the normal form owing to defoliation, the growth system of the damaged trees became fragmented into a wind-exposed (west–ast), horizontal component and a vertical (below–bove snowpack) component outlined by the asymmetric development of stem and foliage. Although cool growing seasons reduce tree-ring growth, frost events in July appear also influential, possibly when killing frosts occur during bud break. The impact of such abrupt events may have a long-enduring influence on radial growth, a factor much neglected in dendroclimatological studies of boreal and subarctic environments. Stem degradation may be initiated by the changing position of the snowpack line associated with variable snow precipitation during several consecutive years, thus inducing a shifting erosional zone along the stem most effective when temperatures are below average, i.e., likely the result of mechanical defoliation caused by the synergistic influence of snow and ice abrasion during blizzards and severe windchill conditions on the brittle, cold-exposed needles. Our results suggest that sustained winter defoliation at treeline has an overwhelming influence on subsequent radial growth. More dendroecological studies and experimental field work are needed to test our conclusions. Keywords: stem analysis, treeline, black spruce, winter defoliation, tree rings, subarctic.

This paper summarizes the 37 year history of net accumulation measurements at the geographic South Pole obtained by numerous investigators using a variety of techniques. These data lead to the conclusion that annual net snow accumulation has increased in the vicinity of South Pole Station (SPS) since 1955. The records were examined for evidence of a “station effect” and it is concluded that not all of the observed increase can be attributed to snow drift associated with the presence of the station. Furthermore, the accumulation increase at the South Pole appears consistent with increases observed at other locations on the East Antarctic Plateau, and in the Peninsula region as well. These data suggest that the recent accumulation increase at SPS may be regionally extensive over the East Antarctic Plateau.

We propose a new modeling method for the appearance of fallen snow formed by snow drift near buildings and other obstacles. Instead of computational fluid dynamics simulation for wind-driven fallen snow, we employ the Pre-computed Radiance Transfer (PRT) technique [Sloan et al. 2002] to handle snowflakes which fly, hit and fall with the wind blowing to all directions around obstacles. This approach approximates snow accumulation with snow drift without heavy fluid dynamics simulation computation.

[1] A regional atmospheric model, with a horizontal grid spacing (Δx) of 14 km, is used to study the surface mass balance components (precipitation, sublimation, and snow drift) in the region of the Antarctic Peninsula (AP). An integration is performed for the 7-year period 1987–1993, using a realistic forcing at the lateral model boundaries and at the sea surface. Output from this integration indicates that the precipitation reaches its maximum value on the northwestern slope of the AP, where the upward motion in the atmosphere is largest. Uplift occurs upstream of the barrier, affecting the precipitation distribution over sea. The effect of the barrier on the precipitation distribution over the Bellingshausen Sea might have important implications for the ocean circulation in this region. The mean precipitation over the grounded ice of the AP (1.20 m water eq yr−1) is 6 times larger than the mean value over all the grounded ice of Antarctica. Our estimates for the surface sublimation and wind transport of snow over the grounding line toward the sea are 9% and 6 ± 1% of the precipitation, respectively. In situ data of the wind distribution at three coastal sites located on the northern, eastern, and western sides of the AP are used to evaluate the modeled wind field, which is important for the snow drift calculations. For two of the three sites considered, the prevailing wind direction and bimodal wind distribution are correctly represented by the model. The calculated distribution of accumulation and ablation due to snow drift shows a complex pattern. The wind removes snow from the spine of the AP, where the near-surface flow field diverges, whereas deposition occurs mainly on the eastern slopes, where the near-surface flow field converges. An intercomparison between two 7-year integrations at different horizontal resolution (Δx = 14 km and Δx = 55 km) shows that the precipitation on the northwestern slope is very sensitive to the model resolution: In the Δx = 14 km integration, precipitation on the northwestern slope is higher than in Δx = 55 km because of higher vertical velocities, resulting in a 35% increase in average precipitation over the grounded ice of the AP.

A 36 year old unemployed man with a history of depression and heavy alcohol consumption presented to the local accident and emergency department with injuries to both feet. The previous night he had been drinking heavily. He had attempted to return home but did not make it and had spent the entire night sleeping outside in a snow drift. He was otherwise fit and well with no allergies, and the only drug that he took regularly was citalopram for his depression. On arrival, he was systemically well with a normal core temperature. Bilateral foot injuries were noted (figure⇓). The more severely affected right foot had a dusky ischaemic appearance, with a clear temperature change at the level of the ankle joint and absent distal pulses. The toes of the left foot were also dusky and cool, with blistering over their dorsal aspect. The distal pulses were weakly palpable in this foot. The patient had no other injuries and all other systems examinations were normal. ### 1 On the basis of the history and examination findings, what is the likely diagnosis? #### Short answer The likely diagnosis is frostbite. This occurs when the temperature of the skin drops to about −0.5°C and tissue freezes, resulting in the formation of intracellular ice crystals and microvascular occlusion. #### Long answer There are three types of peripheral cold injury (box 1).1 2 3 4 #### Box 1 The three types of peripheral cold injury

Snow transportation by wind in potential avalanche fracture zones is a very important parameter for avalanche forecasts. A special battery-powered photoelectric sensor has been developed by the Eidg. Institut für Schnee- und Lawinenforschung, Weissfluhjoch/Davos. The output pulse rate is proportional to the mass flux (units of kg m–2 s–1). Drift particles larger than 50 μm in diameter are classified according to their volumes in five classes. The accuracy of the flux measurement is ±50% and is limited by physical factors and not by the apparatus.

Alfred Wegener initiated the study of the free polar atmosphere with more than 100 kite and tether balloon soundings to above 3000 m at Danmarkshavn, North Greenland, during 1906–09. From this beginning polar aerology advanced through a series of similar point studies to the first full upper air network during the IGY (1957/8). While its replacement by satellite remote sensing is gradually taking shape, the accumulated polar information has been thoroughly analyzed; a series of comprehensive accounts is referenced. The aspects singled out for this review are themes that would have been of special interest to Wegener — the surface energy balance and the polar inversion, the katabatic winds and snow drift, and the aerosols of the polar atmosphere.

A multiple regression analysis has been performed of the average annual number of avalanches and terrain factors. Observations were made at 36 paths at Rogers Pass over a period of 9 years. The average slope inclination measured from the starting point to the beginning of the run-out zone and exposure to wind proved to be the most significant variables. Slope angle at the starting point, variations over the track, and roughness of the ground surface were of secondary significance and their influence varied strongly from site to site. The analysis confirmed that avalanches need either a steep slope or a snow drift to start and a mimimum inclination of track to maintain their motion.

This paper presents the first step in the development of a new kind of computer-based tool which can help a specialist consultant in avalanche path analysis, a knowledge-based or expert system. In considering an avalanche path, the specialist often needs a simulation of possible avalanches on this path in order to obtain data for probable velocities and pressures. Use of classical numerical tools by an engineer requires a great deal of experience and knowledge. Such knowledge exists, but until the development of knowledge-based systems no computer-based tool was available. After a short review of such systems, we describe a knowledge-based system currently being developed in CEMAGREF. Its problem-solving environment includes methods of analysis developed by a senior consultant, and also numerical and qualitative models. In the first step, which is presented here, it analyses the starting zone of an avalanche path. By means of a digital terrain model and a description of vegetation and main ridges (a model which still needs to be improved) this system can make use of the experience of specialists to produce an avalanche-starting simulation based on specified meteorological conditions. Quite simple rules are employed in order to take into account snow drift. First results are shown on accompanying maps of this qualitative modelling and these will need to be tested for validity.

In terms of structural failure, drift loads at changes in roof elevation are the most important snow load. In this paper, present building code provisions and recent research results are reviewed. The mechanics of snow drift formation as well as the parameters that influence these drifts are discussed in depth. Finally, a new empirical relationship for peak drift height and drift load is presented. The input parameters for the new empirical relationship are the width, length, and height of the upper level roof, the elevation difference between the upper level roof and snow on the lower level roof, and the ground snow load. Comparisons with case history measurements indicate that the new empirical relationship is a marked improvement over existing relationships. Key words: snow, loads, roof, drift, fluid mechanics, building codes.

A total amount of the snow drift during a winter is one of the important elements for the design of the facilities which protect railroads and highways from the snowstrom. It was obtained experimentally from the accumulation of snow around the snow-storm prevention forest and from the vertical distribution of drifting snow during the snow-storm, both of which were measured in author's Institute during past few years. On the other hand, the quantity of drifting snow was calculated according to the various formula, being expressed as the function of wind velocity over the snow cover. Comparison of measured values with calculated ones showed that the formula q=cv3 (, where c takes numerical value 0.0139, measuring q and v with g/cm. min. and m/sec. units respectively, ) which was suggested in Soviet Union is satisfactory for estimating the total amount of snow drift from the records of the wind velocity.

The different components in the mass economy of the inner parts of the Antarctic ice cap are treated in some detail. Extrapolation of glaciological and meteorological observations at the coast and recent observations from the interior indicate that over extensive areas snow drift, evaporation, and hoarfrost formation are of minor importance. Precipitation is almost the only source of accumulation. As the observed amounts of atmospheric water vapor are small, the speed of inflowing moist air must be high, but it is compatible with measured meridional wind components at the border of the continent.

To know well of the quantity of drifting snow in the snow fallen district is one of the important elements for the good design of the equipments which protect railroads and the highways from the snowstorm.An adequate measure of snowstorm is progressive in Soviet Union. The quantity of drifting snow was calculated according to the various formula, being expressed as the function of wind velocity over the snow cover.In this report was utilized the formula Qmax=0.0215 V3g/m·sec (where 0.0215 is numerical value, measuring Qmax and V with g/m·sec. and m/sec. unit respectively) which was suggested by D.M.Melnik in Soviet Union.Measured values of wind velocity and snow drift depend upon the data of Minenobu in Hokkaido in Jan-Mar 1965. Measureemnt of the snow drift was obtained experimentally from the accumulation of snow around the test fence.Due to compare the Both of data a few of voluntariness was instituted. The result of that comparision, a ratio of the both of quantity (calculation/measurement) was 0.92 to 1.04. It is high comformity than the first expection.If the wind velocity the temperature and the snowfall are recognized as accuracy data, and the drifting snow times are judge with accuracy, after all estimating of the quantity of drifting snow is possible, these results will be good design data.

The purpose of the research is to settle the following problems.1) How high should the snow fences be ?2) How density ratio should be ?3) How far should they be placed from the track ?As a method of measurements, we installed the slat snow fences various density ratio in field, and then examined snow drift depth and wind velocity distribution around the fence.Investigating the data of measurements, we obtained the following results.1) The following relation between the length from the fence to top of snow dune and density ratio were obtained.When there is no gap below the fence.lm=4.63PHFWhen there is a gap of 60 cm below the fence.lm= (1.84+4.63P) HFlm……the length from the fence to top of snow dune.P……density ratioHF……height of the fence2) At saturation point of the fence with snow drift, the length of the leeward snow dune were obtained each density ratio.3) As a big pocket appear between the slat fence and snow dune, the effects of fence are kept long.

The Waga River is a branch of the Kitami River, and the upper stream flows from north to south with the longitudinal valley in the Ou mountains. The district is the most famous drifted-snow district, and the regional wind directions are very complicated and are influenced by the topography. The writer investigated house types there. (1) In the downer stream district the entrance of main house appears similler to that in the Kitakami lowland. Some houses, however have set up temporary extended entrances with wood and miscanthus. In the upper part this extended entrance becomes a fixed one. These entrances which project from the main houses are 2m in length in the Iwasawa community. This becomes longer as one goes further westward, and reachesl to 2.5m-3m in Oarasawa, 3m-4m in inner districts. (2) The window as a transom becomes larger in size in inner Oarasawa. This is similar to that in the North-Japanese Alps and other drifted snow cistricts. (3) We can not find larmhouses with upstairs in the lower Waga streami but in the upper stream we can find some farmhouses with them in a part of the main house. These differ from those of the silk-raising district. (4) The frontal direction of houses in the lower river districts face the south and are cut down on the east side. In the upper river area, houses face toward the east or southeast side and are cut down on the north or northeast. (5) The writer asked local inhabitants for climatic data-drifted snow and wind directions. The interpretation of a few climatic landscapes are as follow. (7) The inhabitants must remove the snow from their roofs several times a year, so that every house is surrounded by snow laid 3m deep. Therefore, without exception we can find a special entrance, two-story houses and large transom windows for deep snowfall. Moreover, the cutting down of a house will face toward opposite side of the wind direction, because snow drift on the opposite side of wind direction.

Publisher Summary This chapter describes the eolian features shaped by aerodynamic and vorticity processes. Eolian features have a variety of shapes because numerous factors are involved in their formation. One important factor is wind regime, and simpler the wind regime, more likely the streamlined forms develop. The wedge-shaped snow drift, fashioned by concurrent deposition and erosion, is one of the most beautiful shapes in nature. Formed by winds that strip snow from fields, these drifts—which develop by the million—move obliquely across ditches, gutters, and snow banks. These drifts are often formed as resultants between the main wind and that of a deflected flow. It has been observed that once the drifts are formed, their shapes then guide the local flow, which in turn governs subsequent minor changes. Some drifts have inclined crest lines, but on others a considerable portion of the crest line is horizontal, becoming inclined only where the feature narrows leeward in the closure of streamlines over the crest. It is found that closure brings these flow lines closer to the interface, and they begin to create coarse fluting on the sides and across the lee keel.

The development of reliable models of near surface snow-atmosphere interactions from small to large scale is motivated by the need for a better understanding of the fluid- and morpho-dynamic processes in Polar environments. These interactions drive observed spatial patterns of snow distribution, ice deformation, travel and distribution of sea ice, among many others. However, challenges arise when representing the detailed sequence of processes involved, such as aerodynamic entrainment, particle dynamics, feedback on fluid momentum and particle impact on the surface. Here, we test a Lagrangian Stochastic Model of snow particle transport coupled to a Large Eddy Simulation to represent particle dynamics in turbulent flows and momentum extraction caused by suspended particles. An Immersed Boundary Method is adopted to effectively reproduce surface erosion and deposition, both of which influence surface drag and turbulence statistics. The model is implemented to represent snow redistribution over an Antarctic sea ice floe over which pre- and post- storm snow distribution patterns were successfully quantified using a terrestrial laser scanner. The dataset collected in October 2012 as part of the SIPEX-2 indicates marked changes in the snow distribution as a result of particle transport processes, providing valuable testing grounds for the model. The modeled snow surface pattern and the spatially variable shear stress evolve and reciprocally interact, generating areas of preferential deposition and erosion consistent with the observations. Model results and future improvements are discussed.

Two meso-scale numerical models, the Advanced Regional Prediction System ARPS, and a model based on the computational fluid dynamics model CFX-4, were used to simulate very high resolution wind fields above the complex mountainous topography of an Alpine ridge. Using an horizontal mesh resolution of 25x25 m, both models were able to reproduce qualitatively important flow features (change in direction and separation) that had been observed in the field. However, it could also be shown that the boundary conditions strongly influence the results.