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SMAPEx-4 Archive
Soil Moisture Active Passive Experiment

Polarimetric L-band Multibeam Radiometer (PLMR)

Polarimetric L-band Multibeam Radiometer (PLMR)
The Polarimetric L-band Multibeam Radiometer (PLMR) measures both V and H polarisations using a single receiver with polarisation switch at incidence angles ±7°, ±21.5° and ±38.5° in either across-track (pushbroom) or along-track configuration. In the normal pushbroom configuration the 3dB beamwidth is 17° along-track and 14° across-track resulting in an overall 90° across track field of view. The instrument has a frequency of 1.413GHz and band width of 24MHz, with specified NEDT and an accuracy better than 1K for an integration time of 0.5s, and 1K repeatability over 4 hours.
The PLMR calibration accuracy was calculated using ground (sky and blackbody) calibration performed during the SMAPEx experiments. The accuracy of PLMR in the typical brightness temperature range observed over water and land (150–300K) was estimated to be better than 1K at H polarisation and 2.5K at V polarisation (Reference: Panciera, R., "Effect of Land Surface Heterogeneity on Satellite Near- Surface Soil Moisture Observations", PhD Thesis, 2009, The University of Melbourne)
Sensor Polarimetric L-band Multibeam Radiometer
Center frequency (GHz) 1.413 (L-band; 21cm)
Band width (MHz) 24
Polarisation H & V (polarimetric mode optional)
Integration time (s) 0.5
Incidence angle (°) ±7, ±21.5, ±38.5
Beam width 3dB beamwidth is 17° along track and 14° across track resulting in an overall 90° across track field of view.
Radiometric resolution (K) <1
Weight (kg) 46
Dimension (cm) 91.5 × 91.5 × 17.25


PLMR observations

PLMR observations for SMAPEx-4 are available from Download Centre.


Created: February 2016
Last Modified: June 2016
Maintainer: Xiaoling Wu, xiaoling.wu@monash.edu