Radiometer LWP Radiometers

These radiometers are used for the remote sensing of integrated water vapor (IWV) and Liquid Water Path (LWP). Both quantities give column-integrated (total) values rather than vertically resolved profiles.


  • Liquid water path (LWP) measurements
  • Integrated water vapour (IWV) measurements
  • Attenuation monitoring
  • Beacon experiments
  • Cloud observations
  • Climate monitoring
  • Satellite tracking (GPS, Galileo)


The RPG-LWP model is the standard two-channel microwave radiometer typically used for this purpose. Upgraded versions (RPG-LWP-U90, RPG-LWP-U150, RPG-LWP-U72+88) extend the sensitivity to small amounts of LWP (e.g., thin clouds) by adding one or two higher frequency channels. High-frequency two channel versions (RPG-LWP-90-150) are optimised for thin cloud and snow observation. For observation of thick clouds and rain we recommend the dual-polarized Rain Radiometer (LWP-Rain).

LWP23.8 & 31.4 GHz
(23.8/36.5 GHz optional)
Standard two-channel radiometer for estimation of IWV and LWP

The RPG-LWP-XXX series of liquid water path radiometers is meant for measurements of total water vapour (IWV, integrated water vapour) and total cloud water (LWP, liquid water path).

Higher sensitivity to low-density (thin) clouds can be achieved by upgrading the standard LWP radiometer with higher frequencies.
Atmospheric attenuation measurements (e.g., for beacon experiments) can be performed.

LWP-U9023.8, 31.4, 90 GHzImproved sensitivity to thin clouds
LWP-U15023.8, 31.4, 150 GHzImproved sensitivity to thin clouds
LWP-U72-8223.8, 31.4, 72.5, 82.5 GHzImproved sensitivity to thin clouds,
attenuation measurements for data links
LWP-90-15090 & 150 GHzObservation of thin-clouds only.
Ideal extension of all above radiometers in master-slave mode.