Microwave Radiometry and Radiometers for Ocean Applications

The microwave radiometer system measures, within its bandwidth, the naturally emitted radiation – the brightness temperature – of substances within its antenna’s field of view. Thus a radiometer is really a sensitive and calibrated microwave receiver. The radiometer can be a basic total power radiometer or a more stable Dicke radiometer. Also correlation receivers play an important role in modern systems. The radiometer system might be single or dual polarized (horizontal and vertical) – or even be polarimetric, i.e. measure all 4 Stokes parameters, thus providing additional geophysical information at any given frequency. The radiometer system will very often be configured as an imaging system on a spacecraft for example. This normally implies scanning the antenna. Then there are certain relationships (or even conflicts) between achievable radiometric sensitivity/ ground resolution/antenna size, and the problem: scanning antenna/space- craft stability. In many cases good compromises have been reached, as evident recalling the many successful missions throughout the recent 30 years. But in some cases the situation calls for special solutions, like the push-broom system or the synthetic aperture radiometer technique, both yielding imaging capability without scanning. Typical applications of microwave radiometry concerning oceans are: sea salinity, sea surface temperature, wind speed and direction, sea ice detection and classification. However, in an attempt to measure properties of the sea from space, the intervening atmosphere will disturb the process, and corrections might be required. Also, at some frequencies and for some applications, the Faraday rotation in the Ionosphere must be taken into account.


Brightness Temperature Faraday Rotation Ocean Application IEEE Trans Geosci Remote Sensing Microwave Radiometry 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Dicke RH (1946) The Measurement of Thermal Radiation at Microwave Frequencies. Rev Sci Instr 17: 268-279CrossRefGoogle Scholar
  2. Hollinger JP, Lo RC (1984) Low-Frequency Microwave Radiometer for N-ROSS. Large Space Antenna Systems Technology NASA Conference Publication 2368 pp. 87-95Google Scholar
  3. Klein LA, Swift CT (1977) An Improved Model for the dielectric constant of Sea Water at Microwave Frequencies. IEEE Trans Antennas and Propagation 25 (1): 104 - 111CrossRefGoogle Scholar
  4. Laursen B, Skou N (2001) Wind Direction over the Ocean Determined by an Air-borne, Imaging, Polarimetric Radiometer System. IEEE Trans Geosci Remote Sensing 39 (7) 1547-1555CrossRefGoogle Scholar
  5. LeVine DM, Abraham S (2002) The Effect of the Ionosphere on Remote Sensing of Sea Surface Salinity from Space: Absorption and Emission at L Band. IEEE Trans Geosci Remote Sensing 40: 771-782CrossRefGoogle Scholar
  6. LeVine DM, Abraham S (2004) Galactic Noise and Passive Microwave Remote Sensing From Space at L Band. IEEE Trans Geosci Rem Sens 42: 119-129CrossRefGoogle Scholar
  7. Sasaki Y, Asanuma I, Muneyama K, Naito G, Suzuki T (1987) The Dependence of Sea-surface Microwave Emission on Wind Speed, Frequency, Incidence Angle, and Polarization over the Frequency Range from 1 - 40 GHz. IEEE Trans Geosci Rem Sens 25 (2) 138-146CrossRefGoogle Scholar
  8. Skou N (2003) Faraday Rotation and L-band Oceanographic Measurements. Radio Science 38 (4) 24-1 to 24-8CrossRefGoogle Scholar
  9. Skou N, LeVine D (2006) Microwave Radiometer Systems, Design and Analysis. Artech HouseGoogle Scholar
  10. Skou N, Hoffmann-Bang D (2005) L-Band Radiometers Measuring Salinity from Space: Atmospheric Propagation Effects. IEEE Trans Geosci Rem Sens 43 (10):2210-2217CrossRefGoogle Scholar
  11. Ulaby FT, Moore RK, Fung AK (1981) Microwave Remote Sensing, Vol.1. Artech HouseGoogle Scholar
  12. Yueh SH, Wilson WJ, Li FK, Nghiem SV, Ricketts WB (1995) Polarimetric Measurements of Sea Surface Brightness Temperatures Using an Aircraft K-band Radiometer. IEEE Trans Geosci Rem Sens 33 (1) 85-92CrossRefGoogle Scholar
  13. Yueh SH, West R, Wilson WJ, Li FK, Njoku EG, Rahmat-Samii Y (2001) Error Sources and Feasibility for Microwave Remote Sensing of Ocean Surface Salinity. IEEE Trans Geosci Rem Sens 39 (5): 1049-1059CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V 2008

Authors and Affiliations

  • N. Skou
    • 1
  1. 1.Danish National Space CenterTechnical University of DenmarkDenmark

Personalised recommendations