MICCY, Microwave Radiometer

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1. Contact

Dr. Susanne Crewell
Meteorological Institute
University of Bonn
Auf dem Hügel 20
D-53121 Bonn
Germany

Tel.: +49 (0) 228 73 5779
Fax: +49 (0) 228 73 5188
email: screwell@uni-bonn.de
Homepage Susanne Crewell
Homepage MICCY

2. Short Description

MICCY [Crewell et al., 2001] measures the atmospheric emission at 22 frequencies in the microwave region (20-90 GHz). The signal contains contributions from the water vapor, oxygen and cloud liquid water. Principally the water vapor profile can be derived from spectrally resolved measurements of the weak 22.235 GHz water vapour line and  the atmospheric temperature profile via the temperature dependent oxygen emission around the 60 GHz rotational band. The cloud water signal increases roughly with the frequency squared in between both features enabling the retrieval of the liquid water path (LWP) with high accurracy. The polarisation information contained in the measurement may be used to distinguish between cloud and rain liquid water by scattering effects of oblate precipitatin particles [Czekala et al., 2001].

3. Goals within 4D-clouds

4. Instrument Specifications

4.1 General

Measurement quantity

Spectral radiance measured in equivalent Planck-brightness temperatures[K]

Receiver type:

total power radiometer, single sideband at all frequencies

Manufacturer:

Radiometer Physics (RPG, radiometer.physics@t-online.de)

Observation angle:

elevation: 0-90 deg possible, azimuth scanning possible (0-360 deg)

Integration time:

1 s

Dimensions:

3.1 m x 1.5 m x 2.7 m

Weight: 

approx. 2500 kg (including) trailer

Calibration method:

4-point method (using Hot(ambient), Cold(77 K) loads and noise diode) and tipping curve method

4.2 Specific

Frequencies [GHz]:

22.235, 22.985, 23.735, 24.485, 25.235, 25.235, 25.985, 26.735, 27.485, 28.235

50.8, 51.8, 52.8, 53.8, 54.8, 54.8, 55.8, 56.8, 57.8, 58.8

90, 90

Polarization:

H, H, H, H, H, V, V, V, V, V

H, H, H, H, H, V, V, V, V, V

H,V

Beam width* [deg]:

~0.9

~0.55

~0.5

Noise temperature [K]:

~500

~1500

~3000

Bandwidth [MHz]:

250 each

250 each

1000 each

* beam width is defined as FWHM (full width at half maximum)

5. Products

Raw data (Level 0):

Level 0A:

TB_MICC_1s - 22 brightness temperatures with 1 s temporal resolution

10 Mbyte per day

Level 0B:

TB_MICC_1s - 22 brightness temperatures with 1 s temporal resolution (final calibration)

10 MByte per day

Processed data (Level 1):

Level 1:

T_MICC_1s - temperature [K] at 0, 0.25, 0.5,0. 75, 1.0, and every 0.5 km up tp 9.5 km above ground level with 1 s temporal resolution (accuracy is between 1 and 2 K for heights up to 4 km)

10 MByte per day

Level 1:

RH_MIC22_1s - relative humidity [%] at 0, 0.25, 0.5,0. 75, 1.0, and every 0.5 km up tp 9.5 km above ground level with 1 s temporal resolution (accuracy is between 1 and 2 K for heights up to 4 km)

10 MByte per day

Level 1:

LWP_MIC22_1s - liquid water path [gm-2] with 1 s temporal resolution (accuracy is about 20 gm-2)

1 MByte per day

Level 1:

IWV_MIC22_1s - integrated water vapor [kgm-2] with 1 s temporal resolution (accuracy is about 1 kgm-2)

1 MByte per day

Synergetic data (Level 2):

Level 2:

LWC_MIMI_1s - liquid water content [gm-3] every 250 m above ground level with 1 s temporal resolution from MICCY and MIRACLE data (accuracy is about 30-50 %)

10 MByte per day

6. Expected Data within 4D-clouds

Continuous nadir observations at Cabauw from August 1. to September 28., 2001. Angular scans at Cabauw during all aircaft flights (from departure to landing) with microphysics missions in September 2001.