One Two
Sie sind hier: Startseite Messdaten Passive Microwave Radiometer MICCY Specifications

Specifications

Aufbau 1 Atmospheric radiation is received via a scanable planar mirror (left side), which couples the radiation into a Cassegrain system including a 90 cm diameter off-axis paraboloidal mirror. The elevation mirror can also be tilted to the calibration targets, which consist of pyramidal shaped, carbon loaded absorber material. The load in the back is at ambient temperature while the bottom load can be filled with liquid nitrogen.
  • beam width is lower than 1° (full width at half maximum) at all frequencies, which is significantly lower than conventional radiometers in this frequency range. This strongly reduces the 'beam filling' problem, which can lead to non-linearities in the determination of hydro-meteorological parameters, especially in clouds.
  • Azimuth scanning (0-360°) and elevation scanning (0-180°, atmosphere and soil observation possible)
  • absolute accuracy of brightness temperatures of 1K at 1s integration time (2-stage in house temperature stabilization)
  • absolute calibration using either HOT/COLD method or tipping curve method, periodic relative calibration (gain adjustment) using hot load)
  • dimensions (3.1 m x 1.5 m x 2.7 m) and weight about 1800 kg (see drawing)
 
Aufbau 2 MICCY receives atmospheric radiation in three frequency bands:
  • Band A along the high frequency slope of the 22.235 GHz water vapor emission line
  • Band B along the low frequency side of the oxygen complex at about 60 GHz
  • Band C at 90 GHz mostly influenced by cloud absorption
The atmospheric radiation received by the Cassegrain system is separated into the different frequency bands by a quasi-optical multiplexer (see blue box in both figures). The shortest wavelengths (band C) are transmitted through the first dichroic plate (red) while the longer wavelengths are reflected by the first and separated by the second dichroic plate. After separation of the single bands the beams are refocused by elliptical mirrors and mathed to the horn antennas of the single recivers. The -10 dB contours of the single bands are shown in green (A), violett (B) and red (C).  

 

  Band A Band B Band C
Frequency Range [GHz] 22.235-28.235 50.8-58.8 90
Number of channels 10 10 2
Channel distance [MHZ] 750  1000  -
Polarization 5 H, 5 V 5 H, 5 V H & V
Receiver Type SSB SSB SSB
Noise Temperature [K]  ~500  ~1500  ~3000
Beam width [°] ~0.9 ~0.55 ~0.5
Channel bandwith [GHz] 0.25 0.25 1

     

Seite erstellt von Kerstin Ebell
Letzte Änderung: 17.02.2005

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