A research on analysing the feasibility and the benefits obtained from the utilisation of the heat surplus from temperature independent snowmaking systems is proposed. The interest of this research relies on the fact that it is a way of making it viable both economically and environmentally, to use these systems, which are the solution for snow scarcity due to global warming.This will be done by studying the performance of three different alternatives for the installation of a TIS, considering it with and without heat recovery in order to show the importance of the latter. The study will be performed for the ski resort of Astún, in the Spanish Pyrenees, considering the desire to guarantee a ski slope of 3 km from November till end of April. The three cases studied are: • Case I: Temperature Independent Snowmaking system without heat recovery • Case II: Temperature Independent Snowmaking system with direct heat recovery • Case III: Temperature Independent Snowmaking system with direct heat recovery and snow storage The feasibility of each of the cases will be studied based on costs and energy savings and consumptions, while ecological impact, maintenance costs or the interest rates will not be included in order to simplify the results. The heat recovery will be performed thanks to a CO2 heat pump that will deliver over 6 GWh through water at 70 ºC to the residential and commercial buildings of the ski resort. The heat recovery has only been studied in detail for direct recovery, but the possibility of indirect heat recovery would be interesting in other situations, therefore, it has also been briefly described.As a way of introducing and justifying the project, a literature review has been performed, on the impact of climate change and the need for snowmaking, and also on the different snowmaking technologies and their limitations, leading finally to the need for temperature independent snowmaking. Moreover, calculations and simulations including heat transfer, fluid dynamics and theory of refrigeration technology are conducted. Finally, putting that together with estimated investment costs and prices gathered either from available public sources or personal communication with suppliers, the final comparison of the cases is performed.Based on the obtained results, the most suitable solution for the ski resort of Astún, considering the current heat demand of its buildings, is the case II, installation of a TIS with direct heat recovery. This case has a total investment cost of 1.957.464 €, and due to the savings generated from the reused heat, it comes with yearly savings of -249.872 €, which implies a payback time lower than 8 years, making it the most viable alternative.

Les interactions dynamiques des conditions d'enneigement avec l'activité touristique des stations de sport d'hiver reposent sur de multiples enjeux sociaux, économiques, environnementaux et climatiques intégrés par les élus chargés du développement des territoires de montagne et industriels responsables de l'exploitation des domaines skiables. Depuis l'expérience vécue de la vulnérabilité des domaines skiables au déficit d'enneigement au début des années 1990 et plus encore depuis l'introduction des problématiques du changement climatique dans le débat public au début des années 2000, l'attente de la part des décideurs politiques et des professionnels de la neige pour des éléments fiables et pertinents sur l'impact du climat sur l'activité des sports d'hiver - dans laquelle s'intègre ce travail - n'a cessé de croître.Ce travail s'est attaché à la compréhension du rôle intégrateur de l'opérateur de domaine skiable dans son approche socio-économique d'une part et nivo-climatologique d'autre part de la gestion de la neige dans sa station dans le but de développer une chaîne de modélisation de la dynamique des interactions entre les conditions d'enneigement (variabilité, imprévisibilité) et les activités humaines (objectifs, moyens).Un état des lieux a été établi sur les priorités poursuivies, les moyens mis en œuvre (damage, neige de culture) et les contraintes subies (météorologiques, organisationnelles, structurelles) par les gestionnaires de domaines skiables dans leurs opérations quotidiennes de gestion de la neige grâce à une enquête auprès de 55 stations françaises et aux échanges réguliers avec quatre stations partenaires de ce travail (Autrans, Tignes, Chamrousse et Les Deux Alpes).Une modélisation physique des impacts de la gestion de la neige a été développée sur la base d'un modèle de neige et confrontée à des observations réalisées au cours de deux saisons hivernales consécutives dans ces quatre stations partenaires.Ces éléments ont été intégrés dans une chaîne de modélisation couplée permettant des études spatialisées des conditions d'enneigement et in fine la détermination d'indicateurs de la viabilité de l'enneigement à l'échelle de la station, dans l'ensemble des Alpes françaises. Cette méthode extrapolable à l'ensemble des massifs français a été appliquée dans les Alpes françaises sur la période passée 1958 – 2014 et a révélé la corrélation des indicateurs d'enneigement avec les données économiques des stations de sport d'hiver. Notre approche a ainsi montré sa pertinence pour des études prospectives de l'impact du changement climatique et/ou des infrastructures des domaines skiables sur la viabilité de l'enneigement et ses conséquences pour l'activité économique des stations de sport d'hiver. / The industrial activity of ski resorts is based upon multiple concerns including social, economic, environmental and climatic issues which ski resorts stakeholders have to cope with.In the early 1990's ski resorts experienced several consecutive seasons with poor snow conditions in the European Alps when climate and environmental questions were discussed as a global concern after the United Nations held their first international conferences on climate change. This raised the interest of ski resorts stakeholders and representatives of host communities for reliable and relevant indicators of climate induced impacts on snow conditions and on the related economic activity of ski resorts.This research focused on the role played by ski resorts operators in crossing socio-economic concerns with meteorological and snow concerns, to provide a modelling approach of dynamics and interactions between snow conditions (variability, low predictability) and human activities (defined by purposes and means). The objectives pursued by operators, the means they employ (grooming, snowmaking) and constraints they face (meteorological, structural or organization issues) have been investigated through a survey of 55 French ski resorts and frequent discussions with four partner ski resorts (Tignes, Autrans, Les Deux Alpes, Chamrousse). A physically based modelling approach of the impact of grooming and snowmaking on snow properties was integrated in a snowpack model and evaluated with respect to field observations in the four partner ski resorts over two consecutive winter seasons. This was crossed with a socio economic database of ski resorts to provide an explicit spatial modelling of managed snow conditions on ski slopes for the entire French Alps ski resorts. This method was applied for the 1958 - 2014 period and snow indicators were defined and computed, revealing a significant correlation of snow reliability indicators with economic data on ski resorts. This approach therefore proved its ability to provide relevant indicators of snow conditions in ski resorts with respect to economic implications and may be used for further prospective investigations of evolutions of facilities and/or climate change impacts on snow conditions and the related economy of the ski industry.

From the Proceedings of the 1974 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 19-20, 1974, Flagstaff, Arizona / Profiles of snowpack build-up in openings in forest overstories have been widely observed; however, a quantitative characterization of such a snowpack profile would aid in developing empirical guidelines for improving water yields from snowpacks. A technique is outlined that illustrates (a) evaluating snowpack profiles in and adjacent to individual forest openings in terms of increase or decrease in water equivalent, and (b) defining trade-offs between the estimated increase or decrease in snowpack water equivalent and the forest resource removed. Snowpack water equivalent during peak seasonal accumulation was measured in and adjacent to a clearcut strip in a ponderosa pine stand in north-central Arizona. A 4-degree polynomial, which defines the snowpack profile in terms of deposition, redistribution, and ablation characteristics, was empirically selected to describe snowpack water equivalent data points. An increase of 60 percent in snowpack water equivalent was realized by removing 46 percent of the ponderosa pine in the zone of influence, using a strip equal to one and one-half the height of the adjacent overstory.

From the Proceedings of the 1975 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 11-12, 1975, Tempe, Arizona / The quantification of snowpacks in relation to inventory-prediction may be useful in the development of water yield improvement practices involving vegetation management in the mixed conifer forests in Arizona. While mixed conifer forests are relatively limited in extent in Arizona, the potential for water yield improvement by manipulation of snow storage through vegetation management may be high. Sample points on the north fork of Thomas Creek showed high initial snow storage followed by slow melt in association with low forest densities, low potential insolation values, and high elevation. Sample points exhibiting these conditions also possessed maximum storage-duration index values. Low initial snow storage followed by rapid melt was associated with high forest densities, high potential insolation values, and low elevations

From the Proceedings of the 1975 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 11-12, 1975, Tempe, Arizona / The possibility of using imagery from the earth resources technology satellites (ERTS) to monitor changes in areal snow cover in east-central Arizona is examined. Four methods were used in the interpretation of areal snow cover from the ERTS imagery, the densitometer, dot grid, squares grid and projection-planimeter methods providing results of 69, 71, 72 and 74 percent of areal cover respectively. No one method for interpretation of ERTS imagery should be ruled unusable, but any use made of ERTS imagery is dependent upon turn-around time for obtaining the imagery, as snow cover information which cannot be obtained within 24 hours is limited in practical application.

From the Proceedings of the 1975 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 11-12, 1975, Tempe, Arizona / Arizona's continued growth and development depends upon sound management of water resources, especially melted snow which is the primary source of water for the 1.1. Million residents of Maricopa county. The method for snowpack information gathering practiced by watershed specialists of the Salt River project in Arizona is described. The method is outlined, describing aircraft reconnaissance, direct enroute mapping of extent and depth of snowpack, and techniques for identifying ice and/or melt conditions. Under optimal conditions, this technique is considered more than acceptable for determining snowpack levels. Limitations of the technique result from the observer's tolerance of vertigo which can arise under flying conditions; cloud cover, which can reduce contrast and shadows thereby reducing accuracy of observation; and vegetation zones where density of plant matter screens much of the snow.

From the Proceedings of the 1978 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 14-15, 1978, Flagstaff, Arizona / In an effort to improve the methods of forecasting the amount and timing of snowmelt, a primary source of water in Arizona, significant regression equations are developed over a selected measurement period to relate global, direct, and diffuse solar radiation to: (1) the cloud-cover of specific cloud genera, (2) the hour before or after solar noon, and (3) the potential solar radiation. Three regression equations are derived from cloud-cover imagery and solar radiation data collected from two sites in Arizona 's Ponderosa pine forests, Schnebly Hill, and Alpine, in the hope that regression models will be useful in the simulation of snowpack dynamics.

Designing winter cities after the conditions of the winter weather entails unique challenges that require urban planning that is adapted to the specific conditions. One challenge is enabling transportation and accessibility despite heavy snowfall and slippery road surfaces. Understanding these challenges that may arise during the planning and designing of winter cities is crucial for achieving sustainable urban development. As the population increases and climate changes become increasingly unpredictable, winter cities must be planned to optimize land use and create comfortable living spaces. This is essential for preserving important values of nature and cultural values, as well as creating livable environments regardless of the climate. The purpose of this study is to compile and map the challenges of designing winter cities and identify strategies and solutions for sustainable urban planning in cold climates. Through a literature review as a method, a thematization of research and studies in the subject area was compiled and conducted. The thematization resulted in three main themes: Urban design and layout, Operations and maintenance, and Transportation and street space. Thus, the results consist of these themes and associated subheading for each theme. The study shows that winter cities must actively consider multiple aspects, including the need for microclimates, efficient snow clearing, prioritization of soft mobility, and innovative alternatives such as winter trails. Weighing different interests against and considering both practical and aesthetic aspects is crucial in the planning process. The study also highlights the importance of managing conflicts between different modes of transportation and the potential role of winter trails in promoting sustainable mobility. The study suggests exploring alternative solutions for winter trails and how snow management can be made more efficient through further research. This way, urban planners can create sustainable and inviting winter cities for both residents and visitors / Utformningen av vinterstäder efter vinterförhållanden medför unika utmaningar som kräver en stadsplanering som är väl anpassad till de specifika förutsättningarna. En utmaning är att möjliggöra transport och tillgänglighet trots stora snömängder och halt underlag. Förståelsen kring utmaningar som kan uppkomma vid planering och utformning av vinterstäder är avgörande för att uppnå en hållbar stadsutveckling. I takt med att befolkningen ökar och klimatförändringar blir alltmer oförutsägbara måste vinterstäder planeras för effektivisering av markanvändning och behaglig livsmiljö. Detta är viktigt för att bevara värdefulla natur-och kulturvärden, men även för att skapa miljöer som går att bo på oavsett klimat. Syftet med denna studie är att sammanställa och kartlägga utmaningarna med att utforma vinterstäder och identifiera möjliga strategier och lösningar för hållbar stadsplanering i kallt klimat. Genom en litteraturöversikt som metod sammanställdes och utfördes en tematisering av forskning och studier inom ämnesområdet. Tematiseringen mynnade ut i tre huvudteman; Urban design och utformning, Drift och underhåll och Transport och gaturum. Således utgörs resultatet av dessa teman samt tillhörande underrubriker för respektive tema. Studien visar att vinterstäder aktivt måste beakta flera aspekter, bland annat behovet av mikroklimat, effektiv snöröjning, prioritering av mjuk mobilitet samt nytänkande alternativ såsom vinterleder. Att väga olika intressen mot varandra och samtidigt beakta både praktiska och estetiska aspekter är avgörande i planeringsprocessen. Studien framhäver också vikten av att hantera konflikter mellan olika transportmedel samt rollen som vinterleder skulle kunna spela för att främja hållbar mobilitet. Studien föreslår att man utforskar alternativa lösningar för vinterleder samt hur snöhanteringen skulle kunna effektiviseras, detta genom vidare forskning. På så sätt kan stadsplanerare skapa hållbara och inbjudande vinterstäder för både boende och besökare.

From the Proceedings of the 1972 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - May 5-6, 1972, Prescott, Arizona / Inventory-prediction relationships between snowpack conditions and forest attributes may be useful in estimating water yields derived from snow, but such relationships are developed usually from source data collected over a short time period. Analyses of long-term data suggest inventory-prediction relationships developed from limited data may have more general application, however. Available records from 18 snow courses in the ponderosa pine type in Arizona provided source data in this study, which was designed to empirically analyze inventory-prediction relationships developed from long-term snow survey records. The primary hypothesis tested and evaluated by statistically analyzing the family of regression equations representing a snow course, was that, given a precipitation input, the distribution of snowpack water equivalent at peak seasonal accumulation is determined by the spatial arrangement of the forest cover, e.g. basal area. Generally 12 of the 18 snow courses evaluated appeared to support the hypothesis, three courses did not, and three courses were considered inconclusive.