Statically mounted polarsondes at Davis Station 2018/19

Each channel has two photodetectors, one with the analyser polariser oriented parallel to the emitted polarisation, and the other with analyser oriented perpendicular. Meteorology building: Channel 1, vertically polarised light emitted; Channel 2, emitted light polarised 45 degrees to horizontal. Scattering plane horizontal.

Climate Processes and Change building: Channel 1, horizontally polarised light emitted; Channel 2, emitted light polarised 45 degrees to horizontal. Scattering plane vertical. The data are in ASCII text format, recorded once per second and written to hourly log files.

Each day at 0000Z these are archived to a compressed file (tar + gzip), with the date (UTC) of the compressed file creation being included in the filename of the gz file. A quirk of the timing is that a second or two of data from the start of the day are included with the data for the previous day. Also a few seconds of data are generally not recorded at the start of each day due to the computational overhead of the archiving process.

An example line is 2017/03/05 01:59:46 t, 4598358, L, 0.12814012, 0.05185896, 0.40470508, 99.6, C, 0.08772506, 0.06333281, 1.38514388, 99.0, B, 9.0 The data are as follows; Date and time (UTC), "t", seconds elapsed, "L" (channel 1), co-polarised signal, cross-polarised signal, channel 1 depol, LED current (mA), "C" (channel 2), co-polarised signal, cross-polarised signal, channel 1 depol, LED current (mA), "B" (power supply), supply voltage.

(Co- and cross-polarised are with respect to the emitted polarisation, not horizontal or vertical orientations.)