STAR Visibility Data

Data files are in *.dat format where they contain date, time, sensor output voltage (VDC), visibility in (km). To derive the visibility from the VDC the following formula was used: σ km-1 = 20* (0.150/VDC). Visibility 2 (Analog output), was positioned with the 10-m tower automatic weather station (A3) and the Weather Office site.

A Campbell Scientific CR23X data logger was used to log the data. Data files are in a simple *.csv format where they contain date, time, visibility (km). To derive the visibility from the VDC the following formula was used: σ km-1 = 20* (0.150/VDC).

Data from this instrument was downloaded daily during the Fall period and weekly during the winter period. This was accomplished by exchanging the CF card in the data logger. The CF card was then brought into the Environment Canada weather office, where it was offloaded onto the STAR desktop computer.

To exchange the CF cards, the data logger had to be turned off for periods between 1-5 minutes. As a result, 1-5 minutes of data is missing during these time periods. This instrument moved over to the 10-m tower weather station (A3) for the winter blowing snow project (Feb 1- March 30).

The same downloading procedure was adpated , however downloads occurred on a weekly basis. See Visibility 1 Winter metadata form for more info.