The files contain data from NCAR GPS dropsondes AVAPS (Airborne Vertical Atmospheric Profiling System), taken during the Norwegian IPY-THORPEX field campaign from 25 February to 17 March 2008. A description of AVAPS is given in: http://www.eol.ucar.edu/isf/facilities/dropsonde/ The data has been post-processed and quality controlled with the Atmospheric Sounding Processing Environment ... (ASPEN). For more information, see: http://www.eol.ucar.edu/isf/facilities/software/aspen/aspen.html During the campaign period the DLR Falcon 20 was stationed at Andenes airport in Norway and used for flight missions for the study of adverse weather in the Arctic region. The field campaign had a particular focus on polar lows. Two such events was measured during the campaign period, 3-4 March and 17 March. The 3-4 March case was measured by 3 flight missions, documenting the full life cycle of a polar low. The IPY-THORPEX project is described in: http://www.ipy-thorpex.no. A description of each flight, including the flight plans as given in: http://www.pa.op.dlr.de/ipy_thorpex/
Prior to January 1,1993 all coordinates for the province were published with reference to the North American Datum of 1927 (NAD27). Since that date all coordinates are being published with reference to the North American Datum of 1983 (NAD83). For general applications (not requiring precise coordinate conversion between datums), the National Transformation (NTv2)V2.0 software is available for $25.00 from this Division.