Calibration and Validation of Microwave Humidity Sounder onboard
Calibration and Validation of Microwave Humidity Sounder onboard FY-3 D Satellite Yang Guo, Songyan Gu NSMC/CMA Mar. 2018
outline 1. FY 3 D MWHS Introduction 2. Calibration process 3. On-orbit instrument performance 4. Inter-satellite Validation 5. Summary
MWHS Introduction number of channel up to 15 from 5, frequency points from 2 to 4. FY-3 A/B/ MWHS Channel Frequency(GHz) 1 150(V) 2 150(H) 3 183. 31± 1 4 5 183. 31± 3 183. 31± 7 FY-3 C/D MWHTS Channel Frequency(GHz) 1 89. 0 2 118. 75 0. 08 3 118. 75 0. 2 4 118. 75 0. 3 5 118. 75 0. 8 6 118. 75 1. 1 7 118. 75 2. 5 8 118. 75 3. 0 9 118. 75 5. 0 10 150. 0 11 183. 31± 1 12 183. 31± 1. 8 13 183. 31± 3 14 183. 31± 4. 5 15 183. 31± 7 Old Chs. New Chs.
Atmospheric Transmission at Microwave Wavelengths 89 GHz 118 GHz 183 GHz 150 GHz
MWHS Introduction 180± 2º Hot Targets accelerate 270º 90º 287± 2º Cold Space earth scene 306. 65º 53. 35º 0º(Nadir) MWHS scan sequence nonlinearity Radiometer transfer function MWHS instrument
Calibration process Quality control flow chart Calibration flow chart No lunar intrusion If a lunar intrusion
Triangular function Calibration flow chart No lunar intrusion n The variation of Nedt with number of N included in the average of the Space view and internal target counts. Band correction: Planck’s Law: If a lunar intrusion
Calibration flow chart Data_QA_Scan_Flag: ABCDE A_Flag: 0—preprocess success! 1—preprocess Failure! QC_Flag: 0—all channels cal success! 1—Part of the channel cal success! 2—all channels cal Failure! moon. Affect: 0—no lunar contamination! 1—lunar contamination! Geoqc: 00, 01, 02—Geolocation success! 11, 12, 13—Geolocation Failure! Use to compute Then use to compute antenna brightness temperature. Compute scene TBs by antenna correction No lunar intrusion If a lunar intrusion
FY-3 D MWHSII Global Brightness Temperature(Ascending)
FY-3 D MWHSII Global Brightness Temperature(Descending)
Instrument temperature and Warm Target temperature Long-term trends of the internal warm target PRTs averaged temperatures and the instrument temperature
MWHS Warm Target View Count AGC adjustment Long-term trends of Warm Target view counts AGC adjustment
MWHS Noise Equivalent Delta Temperature
Inter-satellite Validation of Observation FY-3 D MWHS VS. Soumi/NPP ATMS Corresponding channels between FY-3 D MWHS and Soumi/NPP ATMS Center Frequency (GHz) 89. 0/88. 2 118. 75 0. 08 118. 75 0. 2 118. 75 0. 3 118. 75 0. 8 118. 75 1. 1 118. 75 2. 5 118. 75 3. 0 118. 75 5. 0 150. 0/165. 5 183. 31± 1. 8 183. 31± 3 183. 31± 4. 5 183. 31± 7 MWHS Channel 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ATMS Channel -----22 21 20 19 18 • Data : 2017. 12. 21 -2017. 12. 30 • Key match-up conditions Ø Difference of observing times < 20 minutes Ø Difference of satellite zenith angles < 5° Ø Distance < 3 km • Uniformity check : STD (3× 3 pixels BT) < 1 K
Inter-satellite Validation of Observation Ch. 11 Ch. 14 Ch. 12 Ch. 13 Ch. 15 Brightness Temperature of MWHS versus that of ATMS
SUMMARY • FY-3 D MWHS(II) on-orbit calibration system has been working well, and the basic calibration data are stable. • The Noise Equivalent Delta Temperature of FY-3 D MWHS(II) is well characterized and meets the specification. • Assessments of FY-3 D MWHS(II) performance will using NWP O-B and site calibration test data.
Thank you!
- Slides: 17