Abstract : 3K.14
Sub-daily model to investigate the time available for artificial snow making

Michael Hofstätter, Herbert Formayer
Institute of Meteorology - University of Natural Resources and Applied Life Sciences

In alpine regions, winter tourism is a very important socio-economic factor. To ensure the snow cover for skiing, the making of artificial snow becomes more frequent.

In respect to a changing climate, it is necessary to give a scientific-based evaluation, how the conditions for artificial snow have changed in recent times and will further develop.

This study takes into account that only hourly-based analysis can lead to appropriate conclusions.

As meteorological data with a temporal resolution of hours and beyond are only available since several years, we developed a model to estimate the temporal evolution of the temperature during the day, based on daily temperature minimum and maximum.

The temporal evolution of the temperature was estimated by two methods with different complexity. A fifth order polynomial regression model, with additional differentiation between clear and cloud covered days defined by the median of the spreadof the diurnal cycle was compared with a simple linear regression model based on temperature minimum and maximum.

Subsequent to the testing of both models, we investigated the time for artificial snow making for our study regions Radstadt and Ramsau, on a monthly base as well as for November-December, a sensitive period for ski opening, and made a climatological comparison of the periods 1961-90 and 1973-2002. Several thresholds ranging from –4 °C to 0 °C where used.