Micro-Wave Humidity Sounder-I (MWHS-I)


The primary purpose of MWHS is moisture sounding in cloudy regions. There are five channels (150–183 GHz) for the early MWHS model as the 150GHz channel is polarized in both vertical and horizontal direction. MWHS has a nominal IFOV of 15 km on surface at nadir. This instrument is similar to the Advanced Microwave Sounding Unit (AMSU)-B that flies on NOAA satellite.

183.31GHz in the microwave frequency bands has the strongest absorption lines to water vapor in the atmosphere. In implementation 183.31GHz is chosen as the primary detection frequency in the vicinity of the three channels set. These microwave radiation show different responses of different atmospheric water vapor levels. You can use 300hPa, 850hPa, 500 HPA and different steam atmosphere heights.

At the same time, the 150GHz mechanism is still in the area of atmospheric window bipolar detection channels, as the background of the Earth's surface for detection of microwave radiation. By comprehensive application of the five channel mechanism for detecting inversion results, you can get the vertical distribution of atmospheric humidity.

Satellite FY-3A FY-3B 
No. Channels 5
Spatial Resolution 16km
Weight 44kg
Power 60W


Channel Center frequency (GHz) Major gas absorption Unilateral bandwidth (MHz) NEΔT(K) Frequency stability (MHz) Antenna beam efficiency Receiver work mode Dynamic range (K)
1 150(V) Window 1000 0.9 50 ≥95% Bilateral 3~340
2 150(H) Window 1000 0.9 50 ≥95% Bilateral 3~340
3 183.31±1 H2O 500 1.1 30 ≥95% Bilateral 3~340
4 183.31±3 H2O 1000 0.9 30 ≥95% Bilateral 3~340
5 183.31±7 H2O 2000 0.9 30 ≥95% Bilateral 3~340

Data and Products

Satellite Instrument Datasets
FY-3B MWHS-I L1 dataL2L3 product
FY-3A MWHS-I L1 dataL2L3 product

Calibration and Validation

MWHS-I calibration and validation