STudies in Atmospheric Radiative Transfer
and Water VApour Effects

Water vapour information from the CHARM sun photometer network

A sun photometer (later versions are known as Precision Filter Radiometers) measures total column water vapour by observing the absorption of radiation in the solar and near-infrared bands. As its name suggests, a sun photometer requires a radiation source, the sun, and while it is making measurements, it tracks the sun across the sky. The disadvantage of a sun photometer is that it can only make measurements while the sun is shining. No data are obtained at night or during overcast conditions which could bias the climate record if water vapour statistics were compiled from this instrument alone. On the other hand, the instrument makes precise measurements and provides simultaneous information on aerosols which allows the link between water vapour and aerosols to be investigated.

In addition to the sun photometer at Bern, water vapour measurements are also being made by the four Precision Filter Radiometers in the CHARM network operated by MeteoSwiss.

Positions of the CHARM PFR stations

Click on a CHARM station to get position information

Station ID:
Station name:
Latitude (deg):
Longitude (deg):
Altitude (m):
CHARM stations

Data download

> Download hourly data

Contactlast update: March 2020