Extreme Temperature Minima in the Gstettneralm Sinkhole with respect to Different Air Masses

From October 2001 to June 2002, a meteorological field experiment was conducted in the 150-m-deep Grünloch (1270 m MSL), a limestone sinkhole near Lunz, Lower Austria, in the eastern Alps (also known as the Gstettneralm Doline). The collected data are completed by some historical data from the thirties of the last century and by ongoing measurements that have been carried out over the last two winter half years (2002-03, 2003-04).

In current works at the Department of Meteorology and Geophysics at the University of Vienna, efforts are being made to investigate the cold air outflow from a basin cold pool and to classify the cold air pool events (i.e. patterns of disturbances) that form in the Grünloch during a disturbed night. To our knowledge, no efforts have been made so far in order to investigate the interrelation between the occurrence of extreme temperature minima in a doline and the properties of the present air mass which can be obtained from measurements in the vicinity of a sinkhole.

For our study, we were able to use data from the Kleiner Hühnerkogel (1601 m MSL), an isolated mountain peak south west of Grünloch and from the Lechner Sattel (1323 m MSL), were we have installed automatic weather stations, as well as synoptic data from Hoher Sonnblick (3106 m MSL), Feuerkogel (1618 m MSL) and Rax (1547 m MSL) which show a high correlation (r > 0.9) to Kleiner Hühnerkogel. Further interest lies in the correlation of remote stations and temperature minima in the doline as a function of different sorts of air masses and under different ambient conditions (e.g. snow cover in the doline/snow-free soil, summer/winter), with regard to the known patterns of disturbances by means of cold air pool events.

Since further field experiments in the Gstettneralm sinkhole are planned, the proposed presentation will deliver a review of current and future research activities. It will put emphasis on the described investigation of temperature minima in correlation with air mass properties. First results will be presented.