scholarly journals New categories for the climatic division of snowy areas in Japan

1998 ◽  
Vol 26 ◽  
pp. 131-137 ◽  
Author(s):  
Masaaki Ishizaka
Keyword(s):  
Temperature Gradient ◽  
Snow Cover ◽  
Air Temperature ◽  
Snow Depth ◽  
Winter Season ◽  
Critical Values ◽  
Absolute Value ◽  
Mean Temperature ◽  
Wet Snow ◽  
The Absolute

New categories for the climatic division of snowy areas according to their snow-cover character in mid-winter are proposed. They are a wet-snow region, a dry-snow region, an intermediate snow region and a depth-hoar region. The wet-snow region is defined as the region in which every layer of deposited snow is wet due to percolation of snowmelt water throughout the winter. In contrast, areas in which the snow cover is dry, at least in the coldest period of the winter season, are classified into two categories, that is the dry-snow region and the depth-hoar region. In the latter region, the small snow depth and low air temperature induce development of depth hoar. The intermediate snow region was introduced to indicate an intermediate character between the dry-snow and wet-snow regions. From the climatic dataset calculated by the Japanese Meteorological Agency and from snow surveys, it has been found that in snowy areas, which have a climatic monthly mean temperature in January (Tjan) higher than 0.3°C, snow would be expected to be wet throughout the winter and, in areas that have Tjan, lower than −1.1°C, to be dry at least in the coldest period. Snow covers, where Tjan is between these two values, are expected to have intermediate characters. Therefore, these temperatures are supposed to be critical values among the wet, dry and intermediate snow regions. The criterion that separates the depth-hoar region from the dry-snow areas was found to be given by a climatic mean temperature gradient. This value lies between 10 and 12°Cm−1, which is derived by dividing the absolute value of the average of the climatic monthly mean air temperature, which is always below 0°C, by the average of the monthly maximum snow depth during January and February.

scholarly journals New categories for the climatic division of snowy areas in Japan

1998 ◽  
Vol 26 ◽  
pp. 131-137 ◽  
Author(s):  
Masaaki Ishizaka
Keyword(s):  
Temperature Gradient ◽  
Snow Cover ◽  
Air Temperature ◽  
Snow Depth ◽  
Winter Season ◽  
Critical Values ◽  
Absolute Value ◽  
Mean Temperature ◽  
Wet Snow ◽  
The Absolute

New categories for the climatic division of snowy areas according to their snow-cover character in mid-winter are proposed. They are a wet-snow region, a dry-snow region, an intermediate snow region and a depth-hoar region. The wet-snow region is defined as the region in which every layer of deposited snow is wet due to percolation of snowmelt water throughout the winter. In contrast, areas in which the snow cover is dry, at least in the coldest period of the winter season, are classified into two categories, that is the dry-snow region and the depth-hoar region. In the latter region, the small snow depth and low air temperature induce development of depth hoar. The intermediate snow region was introduced to indicate an intermediate character between the dry-snow and wet-snow regions. From the climatic dataset calculated by the Japanese Meteorological Agency and from snow surveys, it has been found that in snowy areas, which have a climatic monthly mean temperature in January (Tjan ) higher than 0.3°C, snow would be expected to be wet throughout the winter and, in areas that have Tjan, lower than −1.1°C, to be dry at least in the coldest period. Snow covers, where Tjan is between these two values, are expected to have intermediate characters. Therefore, these temperatures are supposed to be critical values among the wet, dry and intermediate snow regions. The criterion that separates the depth-hoar region from the dry-snow areas was found to be given by a climatic mean temperature gradient. This value lies between 10 and 12°Cm−1, which is derived by dividing the absolute value of the average of the climatic monthly mean air temperature, which is always below 0°C, by the average of the monthly maximum snow depth during January and February.

scholarly journals Changes in Air Temperature and Snow Cover in Winter in Poland

Atmosphere ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 68
Author(s):  
Arkadiusz M. Tomczyk ◽  
Ewa Bednorz ◽  
Katarzyna Szyga-Pluta
Keyword(s):  
Snow Cover ◽  
Air Temperature ◽  
Winter Season ◽  
Primary Objective ◽  
Climatic Conditions ◽  
Cover Depth ◽  
North Eastern ◽  
Northern Regions ◽  
Maximum Air Temperature ◽  
Snow Cover Depth

The primary objective of the paper was to characterize the climatic conditions in the winter season in Poland in the years 1966/67–2019/20. The study was based on daily values of minimum (Tmin) and maximum air temperature (Tmax), and daily values of snow cover depth. The study showed an increase in both Tmin and Tmax in winter. The most intensive changes were recorded in north-eastern and northern regions. The coldest winters were recorded in the first half of the analyzed multiannual period, exceptionally cold being winters 1969/70 and 1984/85. The warmest winters occurred in the second half of the analyzed period and among seasons with the highest mean Tmax, particularly winters 2019/20 and 1989/90 stood out. In the study period, a decrease in snow cover depth statistically significant in the majority of stations in Poland was determined, as well as its variability both within the winter season and multiannual.

A tracking algorithm to identify slab and weak layer combinations for assessing snow instability and avalanche problem type

2021 ◽  
Author(s):  
Benjamin Reuter ◽  
Léo Viallon-Galinier ◽  
Stephanie Mayer ◽  
Pascal Hagenmuller ◽  
Samuel Morin
Keyword(s):  
Snow Cover ◽  
Winter Season ◽  
Essential Element ◽  
Problem Type ◽  
Model Output ◽  
Avalanche Forecasting ◽  
Weak Layer ◽  
Problem Types ◽  
Snow Stratigraphy ◽  
Wet Snow

<p>Snow cover models have mostly been developed to support avalanche forecasting. Recently developed snow instability metrics can help interpreting modeled snow cover data. However, presently snow cover models cannot forecast the relevant avalanche problem types – an essential element to describe avalanche danger. We present an approach to detect, track and assess weak layers in snow cover model output data to eventually assess the related avalanche problem type. We demonstrate the applicability of this approach with both, SNOWPACK and CROCUS snow cover model output for one winter season at Weissfluhjoch. We introduced a classification scheme for four commonly used avalanche problem types including new snow, wind slabs, persistent weak layers and wet snow, so different avalanche situations during a winter season can be classified based on weak layer type and meteorological conditions. According to the modeled avalanche problem types and snow instability metrics both models produced weaknesses in the modeled stratigraphy during similar periods. For instance, in late December 2014 the models picked up a non-persistent as well as a persistent weak layer that were both observed in the field and caused widespread instability in the area. Times when avalanches released naturally were recorded with two seismic avalanche detection systems, and coincided reasonably well with periods of low modeled stability. Moreover, the presented approach provides the avalanche problem types that relate to the observed natural instability which makes the interpretation of modeled snow instability metrics easier. As the presented approach is process-based, it is applicable to any model in any snow avalanche climate. It could be used to anticipate changes in avalanche problem type due to changing climate. Moreover, the presented approach is suited to support the interpretation of snow stratigraphy data for operational forecasting.</p>

scholarly journals Changes in Snow Storage in the Upper Hron River Basin (Slovakia)

2014 ◽  
Vol 10 (2) ◽  
pp. 145-160
Author(s):  
Katarína Kotríková ◽  
Kamila Hlavčová ◽  
Róbert Fencík
Keyword(s):  
Snow Cover ◽  
Snow Depth ◽  
Satellite Images ◽  
Snow Water Equivalent ◽  
Winter Season ◽  
Kendall Test ◽  
Measured Data ◽  
Time Step ◽  
Snow Storage ◽  
Snow Water

Abstract An evaluation of changes in the snow cover in mountainous basins in Slovakia and a validation of MODIS satellite images are provided in this paper. An analysis of the changes in snow cover was given by evaluating changes in the snow depth, the duration of the snow cover, and the simulated snow water equivalent in a daily time step using a conceptual hydrological rainfall-runoff model with lumped parameters. These values were compared with the available measured data at climate stations. The changes in the snow cover and the simulated snow water equivalent were estimated by trend analysis; its significance was tested using the Mann-Kendall test. Also, the satellite images were compared with the available measured data. From the results, it is possible to see a decrease in the snow depth and the snow water equivalent from 1961-2010 in all the months of the winter season, and significant decreasing trends were indicated in the months of December, January and February

scholarly journals On the Role of Snow Cover in Depressing Air Temperature

2008 ◽  
Vol 47 (7) ◽  
pp. 2008-2022 ◽  
Author(s):  
Thomas L. Mote
Keyword(s):  
Boundary Layer ◽  
North America ◽  
Snow Cover ◽  
Air Temperature ◽  
Snow Depth ◽  
Cloud Cover ◽  
Effect Of Temperature ◽  
Temperature Changes ◽  
Temperature Depression

Abstract This study empirically examines the role of snow depth on the depression of air temperature after controlling for effect of temperature changes above the boundary layer. In addition, this study examines the role of cloud cover, solar elevation angle, and maximum snow-covered albedo on the temperature depression due to snow cover. The work uses a new dataset of daily, gridded snow depth, snowfall, and maximum and minimum temperatures for North America from 1960 to 2000 in conjunction with 850-hPa temperature data for the same period from the NCEP–NCAR reanalysis, version 1. The 850-hPa temperatures are used as a control to remove the effect of temperature changes above the boundary layer on surface air temperatures. Findings from an analysis of variance demonstrate that snow cover can result in daily maximum (minimum) temperature depressions on average of 4.5°C (2.6°C) for snow depths greater than 10 cm over the grasslands of central North America, but temperature depressions average only 1.2°C (1.1°C) overall. The temperature depression of snow cover is shown to be reduced by increased cloud cover and decreased maximum albedo, which is indicative of denser forest cover. The role of snow melting on temperature depression is further explored by comparing days with maximum temperatures above or below freezing.

scholarly journals A numerical model to simulate snow-cover stratigraphy for operational avalanche forecasting

1992 ◽  
Vol 38 (128) ◽  
pp. 13-22 ◽  
Author(s):  
E. Brun ◽  
P. David ◽  
M. Sudul ◽  
G. Brunot
Keyword(s):  
Numerical Model ◽  
Snow Cover ◽  
Winter Season ◽  
Weather Conditions ◽  
Internal Layers ◽  
Avalanche Forecasting ◽  
Snow Metamorphism ◽  
Wet Snow ◽  
Made In ◽  
Snow Samples

AbstractLaws of snow metamorphism have been introduced in a numerical model which simulates the evolution of temperature, density and liquid-water profiles of snow cover as a function of weather conditions.To establish these laws, the authors have summarized previous studies on temperature gradient and on wet-snow metamorphism and they have also conducted metamorphism experiments on dry or wet fresh-snow samples. An original formalism was developed to allow a description of snow with parameters evolving continuously throughout time.The introduction of laws of metamorphism has improved significantly the derivation of the settlement of internal layers and of snow-covered albedo, which depend on the simulated stratigraphy, i.e. the type and size of snow grains of different layers of the snow cover.The model was tested during a whole winter season without any re-initialization. Comparison between the simulated characteristics of the snow cover and the observations made in the field are described in detail. The model proved itself to be very efficient in simulating accurately the evolution of the snow-cover stratigraphy throughout the whole winter season.

scholarly journals Simulation of Snowmelt in a Subarctic Spruce Woodland: Scale Considerations

2000 ◽  
Vol 31 (4-5) ◽  
pp. 301-316 ◽  
Author(s):  
Ming-ko Woo ◽  
Mark A. Giesbrecht
Keyword(s):  
Snow Cover ◽  
Snow Depth ◽  
Depth Distribution ◽  
Information Loss ◽  
Grid Size ◽  
Absolute Value ◽  
The Mean ◽  
The Difference ◽  
A Site ◽  
Cover Pattern

Subarctic woodlands comprise stands of spruce trees with varying degrees of openness, giving rise to large contrasts in melt rates within the forest. The spatial variability of the changing snow depth during a melt season was investigated at three scales (2,4 and 16 m), using an example from a site in Yukon, Canada, where the computation of snowmelt takes into account the differential rates within the woodland. During the melt period, the mean daily snow depth decreases but the variability increases as continued ablation leads to greater unevenness of the snow cover. At the three scales of representation, increasing the grid size results in a reduction in the standard deviation and the skewness of depth distribution. The blurring of snow cover pattern at the larger scales is due to a loss in information, considered as the absolute value of the difference in snow depth calculated at two scales for the same location. This loss increases as the snow depth becomes more variable during the melt season. Knowledge of the scale-induced information loss is relevant to the modelling of snowmelt that exhibits large spatial variations.

scholarly journals Preliminary Research on Physical and Mechanical Properties and Avalanche of Seasonal Snow Cover at the Avalanche Station In T'ien-shan, China

1980 ◽  
Vol 26 (94) ◽  
pp. 515 ◽  
Author(s):  
Zhang Xiangsong ◽  
Wang Yanlong
Keyword(s):  
Snow Cover ◽  
Snow Depth ◽  
Physical And Mechanical Properties ◽  
Large Temperature ◽  
Snow Avalanches ◽  
Seasonal Snow ◽  
Mechanical Hardness ◽  
Wet Snow ◽  
Preliminary Research ◽  
Seasonal Snow Cover

Abstract The mountains of western and central T’ien-shan have extensive snow cover and consequent avalanches, however conditions in this area of central Asia are different from those in many other regions with avalanches. Snow cover is not very thick but it experiences very large temperature gradients which dominate its metamorphism, thus depth hoar forms extensively and becomes the principal snow type, so the density therefore remains low as does mechanical hardness. Avalanching activity and total volume vary enormously from year to year; 1968-69, with 211 avalanches of 147 000 m3, accounts for 53% of the avalanches and 75% of the volume of all the avalanches in the seven years 1967-74 in the area of the Gunes avalanche station. Although they can occur from November to April, the main months are January and March with a minimum in February. A snow depth of 50-60 cm is needed for avalanching. Below —10°C dry-snow avalanches occur, while above about —5°C wet-snow avalanches happen. These are often caused by melt water penetrating rapidly through the extensive depth hoar and initiating full-depth avalanches.

scholarly journals Spatiotemporal dynamics of snow cover based on multi-source remote sensing data in China

2016 ◽  
Vol 10 (5) ◽  
pp. 2453-2463 ◽  
Author(s):  
Xiaodong Huang ◽  
Jie Deng ◽  
Xiaofang Ma ◽  
Yunlong Wang ◽  
Qisheng Feng ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Snow Cover ◽  
Snow Depth ◽  
Winter Season ◽  
Remote Sensing Data ◽  
Microwave Remote Sensing ◽  
The Tibetan Plateau ◽  
Optical Remote Sensing ◽  
The North ◽  
The Mean

Abstract. By combining optical remote sensing snow cover products with passive microwave remote sensing snow depth (SD) data, we produced a MODIS (Moderate Resolution Imaging Spectroradiometer) cloudless binary snow cover product and a 500 m snow depth product. The temporal and spatial variations of snow cover from December 2000 to November 2014 in China were analyzed. The results indicate that, over the past 14 years, (1) the mean snow-covered area (SCA) in China was 11.3 % annually and 27 % in the winter season, with the mean SCA decreasing in summer and winter seasons, increasing in spring and fall seasons, and not much change annually; (2) the snow-covered days (SCDs) showed an increase in winter, spring, and fall, and annually, whereas they showed a decrease in summer; (3) the average SD decreased in winter, summer, and fall, while it increased in spring and annually; (4) the spatial distributions of SD and SCD were highly correlated seasonally and annually; and (5) the regional differences in the variation of snow cover in China were significant. Overall, the SCD and SD increased significantly in south and northeast China, and decreased significantly in the north of Xinjiang province. The SCD and SD increased on the southwest edge and in the southeast part of the Tibetan Plateau, whereas it decreased in the north and northwest regions.

scholarly journals The Development of Ski Areas in Romania. What Environmental, Political, and Economic Logic?

2020 ◽  
Vol 13 (1) ◽  
pp. 274
Author(s):  
Sorina Cernaianu ◽  
Claude Sobry
Keyword(s):  
Statistical Analysis ◽  
Snow Cover ◽  
Environmental Sustainability ◽  
Snow Depth ◽  
Winter Season ◽  
The Status ◽  
Ski Areas ◽  
Potential Impact ◽  
Low Efficiency ◽  
Snow Conditions

In the last years, Romania has made major efforts to develop the skiing areas and some important projects have been implemented in the Carpathian Mountains. This research highlights the low efficiency of ski slopes and ski areas concerning the functionality during the winter season, even though a number of investments have been made. Some examples of bad practices regarding the development of skiing infrastructure in link with the potential impact on the environment are presented. The status of ski slopes, slope conditions, and snow depth were collected daily, during the 2016–2017 and 2017–2018 winter seasons, from a Romanian website specialized in snow cover information. A statistical analysis based on the collected data has been done. The 225 ski slopes studied have been opened, on average, less than 62 days and more than 20% of them have not even been opened. Only 17.8% of the slopes complied with the “100-day rule” during the first season and 21.3% of them during the second one, which does not ensure profitability. In conclusion, too many ski slopes have been created without considering the actual snow conditions. The investors wasted capital that is unprofitable and needlessly, affecting the environmental sustainability.

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