Heavy air temperature inversion experienced at Tron

The new mountain station at Tron has shown higher temperatures than the meteorological station in the valley below this cold winter of 2009/2010.

Air temperature development (daily mean values) for the period September 2009 - January 2010 for Tron BH1 (1630 m a.s.l.) and the closeby meteorological station Tynset – Hansmoen (482 m a.s.l.)

December 2009 - January 2010 has provided low air temperatures in great parts of southern Norway. The meteorological station Tynset - Hansmoen at 482 m a.s.l. in the county of Hedmark is situated 3 km north of the uppermost borehole site at Tron at 1630 m a.s.l. At Tynset - Hansmoen the air temperatures have dropped down to –42.4 °C (08.01.2010), with daily mean values down to –40.6 °C (07.01.2010) during this period (met.no). For a comparison the mean monthly temperature (1961-1990) for this station is –10.8 °C for December and –13.5 °C for January, but the record of lowest measured temperature (–46.1 °C) was not broken.

At Tron borehole 1 (1630 m a.s.l.) air temperatures were considerably higher. There the lowest daily mean value was –21.8 °C (07.01.2010). Fig. 1 shows the air temperature development (daily means) at the two sites. Usually air temperatures decrease with altitude, however, in this case there is a major temperature inversion (i.e. temperatures increase with altitude) during the period of lowest temperatures. This is a so-called radiation inversion, which results from cooling of the surface. On cloud-free conditions with little or no wind, longwave radiation emitted by the ground surface easily escapes to space. This lowers the surface air temperature, which in turn chills the air immediately in contact with it. In calm wind situations such air masses may be stable for prolonged time.

At the moment we only have air temperatures from the uppermost borehole at Tron (which we can download via a GSM modem), but when we get temperature data from the other air temperature installations at Tron we can investigate the thickness of the inversion layer in some more detail.

Tags: Cryolink, Tron, Temperature inversion By Herman Farbrot
Published Feb. 2, 2010 10:02 AM - Last modified Mar. 31, 2011 3:08 PM