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CS120A and CS125 Visibility and
Present Weather Sensors
1. Introduction
The CS120A is a visibility sensor. The CS125 additionally detects and reports
present weather in the form of SYNOP, METAR or NWS codes. The CS125
has the same specification for visibility measurement as the CS120A. It is
possible to upgrade a CS120A to a CS125, please contact Campbell Scientific
for more details.
The sensors are infra-red forward scatter visibility and present weather sensors
for automatic weather stations including road, marine and airport based
stations. They both use the well-established forward scatter system for
visibility measurement, utilising a 42º scatter angle. The CS125 uses high
speed sampling to reduce missed events and improves response to other
suddenly changing conditions.
The CS125 has a temperature sensor mounted in the cross arm used as part of
the process for identifying precipitation.
When an optional CS215 temperature and RH sensor is connected, the CS125
can distinguish wet and dry obscuration (for example mist and haze) and make
more precise discrimination between liquid and frozen precipitation.
Dew heaters are provided to keep the sensor optics clear of condensation and
more powerful hood heaters to prevent the build up of snow or ice.
This sensor is certified for Aviation use by the German Meteorological Service,
Deutscher Wetterdienst (DWD).
