Clear Snow Research Articles

Can snow depth be used to predict the distribution of the high Arctic aphid Acyrthosiphon svalbardicum (Hemiptera: Aphididae) on Spitsbergen?

BackgroundThe Svalbard endemic aphid Acyrthosiphon svalbardicum (Heikinheimo, 1968) is host specific to Dryas octopetala L. ssp octopetala (Rosaceae). It has been hypothesized that the aphid is present on those areas with a thin winter snow cover and which therefore clear of snow earlier in the season. This early snow clearance results in a longer growing period and allows the aphid to experience at least the minimum number of degree days required to complete its life cycle. However, this hypothesis lacked a detailed field validation. We aimed to test the relationship between the aphid distribution and time of snow clearance at landscape scale, mapping snow depth at peak of snow accumulation for the two succeeding years 2009 and 2010 and examining site occupancy and plant phenology the following summers. Additionally, the distribution range mapped by Strathdee & Bale (1995) was revisited to address possible changes in range along the coast of the fjord.ResultsA linear relation between snow depth and timing of snow melt was found but with strong inter-annual and landscape variation. Both snow depth and plant phenology were found to affect patch occupancy. In August, the aphid, at the three life stages scored (viviparae, oviparae/males and eggs), was present most frequently in those D. octopetala patches with the most advanced plant phenology and which showed shallower snow depths in spring. However, many patches predicted to contain aphids were empty. The aphid distribution range has expanded 4.7 km towards the fjord mouth from 1995.ConclusionsSnow depth alone, and hence date of snow clearance, cannot precisely define species distribution at landscape scale, as this cannot explain why are they unoccupied patches under shallow snow depths with advanced plant phenology. We nonetheless present a model Arctic system that could form the basis for long term monitoring for climate- driven species shifts.

The detection of cloud-free snow-covered areas using AATSR measurements

Abstract. A new method to detect cloud-free snow-covered areas has been developed using the measurements by the Advanced Along Track Scanning Radiometer (AATSR) on board the ENVISAT satellite in order to discriminate clear snow fields for the retrieval of aerosol optical thickness or snow properties. The algorithm uses seven AATSR channels from visible (VIS) to thermal infrared (TIR) and analyses the spectral behaviour of each pixel in order to recognize the spectral signature of snow. The algorithm includes a set of relative thresholds and combines all seven channels into one flexible criterion, which allows us to filter out all the pixels with spectral behaviour similar to that of snow. The algorithm does not use any kind of morphological criteria and does not require the studied surface to have any special structure. The snow spectral shape criterion was determined by a comprehensive theoretical study, which included radiative transfer simulations for various atmospheric conditions as well as studying existing models and measurements of optical and physical properties of snow in different spectral bands. The method has been optimized to detect cloud-free snow-covered areas, and does not produce cloud/land/ocean/snow mask. However, the algorithm can be extended and able to discriminate various kinds of surfaces. The presented method has been validated against Micro Pulse Lidar data and compared to Moderate Resolution Imaging Spectroradiometer (MODIS) cloud mask over snow-covered areas, showing quite good correspondence to each other. Comparison of both MODIS cloud mask and presented snow mask to AATSR operational cloud mask showed that in some cases of snow surface the accuracy of AATSR operational cloud mask is questionable.

STUDY ON COMMON SPACE’S SNOW MEASURES OF PUBLIC HOUSING IN SNOWY DISTRICT

This study has conducted a questionnaire with field work in Aomori, Hirosaki and Hachinohe city to find out common space’s utilization and snow measures of public housing during winter.As a result, five follows: 1) Corridor is effective as the place to keep Snow processing tool and to put the plant. 2) Garbage box at common space of outside is to keep away snow by residents. 3) Snow removal place is necessary to put snow and snow shoveling tools. 4) The problems of snow for the senior resident is the physical fatigue to clear snow.

Detection of Snowmelt Using Spaceborne Microwave Radiometer Data in Eurasia From 1979 to 2007

Determining the date of snowmelt clearance is an important issue for hydrological and climate research. Spaceborne radiometers are ideally suited for global snowmelt monitoring. In this paper, four different algorithms are used to determine the snowmelt date from Scanning Multichannel Microwave Radiometer and Special Sensor Microwave/Imager data for a nearly 30-year period. Algorithms are based on thresholding channel differences, on applying neural networks, and on time series analysis. The results are compared with ground-based observations of snow depth and snowmelt status available through the Russian INTAS-SSCONE observation database. Analysis based on Moderate Resolution Imaging Spectroradiometer data indicates that these pointwise observations are applicable as reference data. The obtained error estimates indicate that the algorithm based on time series analysis has the highest performance. Using this algorithm, a time series of the snowmelt from 1979 to 2007 is calculated for the whole Eurasia showing a trend of an earlier snow clearance. The trend is statistically significant. The results agree with earlier research. The novelty here is the demonstration and validation of estimates for a large continental scale (for areas dominated by boreal forests) using extensive reference data sets.

Potential of transferring car trips to bicycle during winter

In this Swedish study, the attitudes towards cycling during winter in general, and in relation to winter maintenance of cycleways in particular, is examined. Questionnaires were answered by a thousand employees at four major companies in two Swedish cities. There was a clear difference in mode choice between seasons. The number of car trips increased by 27% from summer to winter while the number of bicycle trips decreased by 47%. The number of car trips increased with distance while the number of bicycle trips decreased, and the decrease was even more significant in winter than in summer. There was a difference in opinion between different categories of cyclists, on what factors influenced the choice of transport mode for the journey to work. Temperature, precipitation, and road condition were the most important factors to those who cycled to work in summer but not in winter. Exercise was the most important to those who cycled frequently in winter, and travel time the most important to those who never cycled to work. By improving winter maintenance service levels on cycleways, it might be possible to increase the number of bicycle trips during winter by 18%, representing a corresponding decrease in the number of car trips of 6%. To increase cycling during winter, snow clearance was found to be the most important maintenance measure. Skid control was not considered as important for the choice of mode, although important to attend to for safety reasons.

More Effective Winter Maintenance Method for Cycleways

Increased cycling as a means of personal travel could generate environmental benefits if associated with a corresponding decrease in car-based transport. For promoting cycling during winter, the maintenance service level of cycleways is of importance. Earlier studies indicated that the Swedish public is unsatisfied with the service levels provided on cycleways during winter. In Sweden, cycleways normally are cleared of snow through plowing and are gritted for skid control. Field studies tested an unconventional winter maintenance method that uses a power broom for snow clearance and salt for deicing. The field studies were evaluated through road-condition observations, measurements of friction, a questionnaire survey, interviews, and bicycle measurements. The method of using a power broom for snow clearance and salt for deicing provided a higher service level than traditional winter maintenance methods, but it was two to three times more expensive. The method has greater potential in regions, such as southern Sweden, with low snow accumulations but with major ice-formation problems than in regions with a colder climate. Cyclists noticed the improved maintenance service level provided with the method used in the field study, but although cyclists stated that road condition is important to their decision to cycle, it could not be concluded that the enhanced service level generated a higher winter cycling frequency.

The municipal engineer's role in winter emergencies

Unlike other parts of the UK, snow of any significance in Kent is infrequent. Kent County Council (KCC) budgets for 60 complete salting runs each year with no allocation for snow or ice clearance. Only when snow or ice is more than 50 mm deep, or ice remains for more than a couple of days, does KCC declare a ‘snow or ice emergency’. The management of such emergencies can stretch the council's resources when other parts of the country treat them as routine occurrences. This paper describes briefly how KCC plans for winter salting and snow clearance and the decision process it has in place for taking action.

The municipal engineer's role in winter emergencies

Unlike other parts of the UK, snow of any significance in Kent is infrequent. Kent County Council (KCC) budgets for 60 complete salting runs each year with no allocation for snow or ice clearance. Only when snow or ice is more than 50 mm deep, or ice remains for more than a couple of days, does KCC declare a ‘snow or ice emergency’. The management of such emergencies can stretch the council's resources when other parts of the country treat them as routine occurrences. This paper describes briefly how KCC plans for winter salting and snow clearance and the decision process it has in place for taking action.

Careful Perusal of Reports on Slip, Trip and Fall Accidents Revealed the Need for Improved Orderliness at Workplaces

Contributing factors to slips, trips and falls at work have been studied in 1.600 accident reports. Both older male and female workers had higher rates of reported STF accidents, but no significant gender or age differences were noted with regard to the factors contributing to the accidents. In the case of both men and women a lack of orderliness at the workplace was the most prevalent contributing factor to the accident. For a successful prevention of STF accidents, improved orderliness, better ladders, reliable safety devices and an effective snow clearance are needed together with a proper sense for the realism in initiated undertakings.

Snow quality in the city of Luleå, Sweden — time-variation of lead, zinc, copper and phosphorus

The quality of urban snow was studied with regard to how the concentrations of selected metals and phosphorus vary over time. The area studied is situated in northern Sweden (65°36′ N; 22°13′ E). Snow samples were taken at three different locations in the city centre, approximately every second week, throughout winter. This study has clearly shown the importance of local conditions and snow clearance operations on snow quality. The study also shows that it is difficult to interpret and predict the concentrations of lead, zinc, copper and phosphorus in the snow. However, it should be possible to predict the mass loads of these substances from the deposition velocities, if the snow handling methods and routines, as well as the local circumstances are known.

Safety and Emergency Services

With particular reference to the seven airports administered by the British Airports Authority (BAA), the high standard of safety and operational efficiency is maintained wherever possible by monitoring and annual inspections conducted throughout the organisation. A typical example concerns the detailed ground inspections augmented by those undertaken from the air of each airport's visual aids to navigation. A specially equipped Turbo Commander aircraft with a nose mounted camera is used for these which enables photographic inspections to be made of the runway and approach lighting. Another demanding area is the provision of equipment to deal with the most severe weather conditions envisaged. Widespread disruption of services will result unless rapid action is forthcoming. Ice warning and detection system are therefore installed at all the airports (Heathrow, Gatwick, Stansted, Glasgow, Edingburgh, Prestwick and Aberdeen) with the most severe conditions being experienced at Aberdeen where a high standard of equipment and planning has ensured that periods of closure for snow clearance are the shortest possible.

Breeding biology and population dynamics of Ringed plovers Charadrius hiaticula in Britain and Greenland: nest‐predation as a possible factor limiting distribution and timing of breeding

The nesting of Ringed plovers was investigated in 1974 at Mestersvig, north‐east Greenland, and in 1974–76 at Lindisfarne, north‐east England. Difficulties in the use of Nest Record Cards for this species (to obtain information from more sites) are discussed. Territory sizes tended to be smaller, and more feeding took place within territories, at Lindisfarne than at Mestersvig. Clutch sizes were similar in different areas. Incubation (mean period about 25 days) was shared fairly equally by the two sexes. Longer incubation shifts at Mestersvig and some areas at Lindisfarne than at other Lindisfarne sites were associated with greater distances between nests and feeding areas. Most egg losses were probably due to predation, and were fewer in the Arctic than in Britain, where nesting success varied greatly in different areas and years, and in relation to timing within a season. Up to five nestings per pair per year were made at Lindisfarne, but only one at Mestersvig.The timing of breeding is discussed, and it is concluded that the date of start of egg‐laying in north‐east Greenland is determined by the timing of snow clearance, while that at Lindisfarne is related to the decreasing probability of egg‐predation later in the season. Because of the high nest losses, the production of young at many temperate sites, including parts of Lindisfarne, was probably inadequate for the population to be self‐supporting. The reasons for the large seasonal, annual and geographical differences are discussed. It is concluded that increasing predation probably determines the southern nesting limits of Ringed plovers, but that this limit may be modified by varying degrees of different types of natural and artificial protection, and extent of habitat suitable for egg camouflage. Increased human usage of nesting beaches probably has an adverse effect on nesting success, but because of the complexity of the number of inter‐related factors affecting the latter, without field experiments it is difficult to predict how this could best be offset by protection measures.

Short-term climate change and New Zealand temperatures during the last millennium

MANY theories have been proposed to explain the climatic fluctuations which produced the sequence of glacial–interglacial periods of the order of tens of thousands of years which have occurred throughout the Quaternary. These fluctuations represent temperature changes in the temperate regions of about 6 °C between a glacial and an interglacial situation. There are also climatic fluctuations with a period of the order of about a thousand years representing temperature changes of about 2 °C. These changes are believed to have had an important bearing on human history, but have been little studied because it is difficult to obtain accurate temperature records for past periods. Shorter temperature fluctuations of the order of a few decades, and representing temperature changes of perhaps as much as one degree, are of considerable economic importance and merge into the developing field of long-term meteorological forecasting. Considerable interest has recently developed in short-term climate changes. If detailed long-term climatic records could be obtained for extended periods in the past it might be possible to determine the causes for the climatic variation, and hence predict future climate trends. Even a knowledge of how hot/cold or dry/wet a particular region's climate could become, and with what probability, would be of considerable economic value to planners involved in hydroelectric development, irrigation schemes, snow clearance and the development of arid and polar regions. At present instrumental records have existed only since the mid-seventeenth century for central England, and for most other areas only over a little more than a century. Cave deposits (speleothems) provide stratigraphy which has a high inherent time resolution. Data for studying short-term temperature fluctuations can be obtained by measuring the 18O/16O ratio of suitable stalagmites1. This technique should enable a high resolution temperature curve to be produced for many regions of the globe. We report here an investigation on the 18O/16O profile through a New Zealand stalagmite which was undertaken partly to evaluate the feasibility of obtaining high time resolution data from speleothem material and partly to compare the temperature record from New Zealand (in the Southern Hemisphere and a region meteorologically unrelated to Europe) with the English climate curve, which is the most firmly established climate curve for the last millennium. Such proxy data given us the possibility of obtaining long-term high resolution temperature records from some of the critical regions of the world where meteorological records either do not exist or are of very short duration.

The influence of snow conditions on the date of breeding of wading birds in north‐east Greenland

The young of wading birds that breed in some parts of the arctic hatch when their insect food supply is most abundant. This appears to be the ultimate factor determining the date of egg‐laying. In various other arctic birds the date of breeding may be influenced, directly or indirectly, by the time at which snow or ice melts. The Joint Biological Expedition to N.E. Greenland 1974 studied Ringed plovers Charadrius hiaticula, Dunlins Calidris aplina, Sanderlings Calidris alba, Knots Calidris canutus, and Turnstones Arenaria interpres breeding in various areas within 80 km of each other.In 1974 the thaw was two or three weeks later than normal in the region. The time at which snow cleared and the dates of breeding of the waders differed considerably between valleys: breeding was delayed in valleys that cleared late. In all areas egg‐laying ceased early in July, probably because chicks hatching from eggs laid later would not be ready to migrate by the end of the summer. Hence the mean date and length of the egg‐laying period were determined by the date of snow clearance from the breeding areas.Studies of the potential food resources indicate that the waders in N.E. Greenland do not appear to time their breeding so that the young hatch at some peak of food abundance. Sufficient food resources are probably available over a long period of time.

Snow Clearance on Railways

Abstract The prevention of snow accumulation on the tracks of railways in Great Britain. Various methods of removal, once lines have been blocked, are discussed in the light of the comparatively small snowfalls in the British Isles.

Snow Clearance on Railways

AbstractThe prevention of snow accumulation on the tracks of railways in Great Britain. Various methods of removal, once lines have been blocked, are discussed in the light of the comparatively small snowfalls in the British Isles.