Calibration and Validation of Microwave Humidity Sounder onboard FY-3D Satellite Yang Guo, Songyan Gu NSMC/CMA Mar. 2018

outline FY3D MWHS Introduction Calibration process On-orbit instrument performance Inter-satellite Validation Summary

MWHS Introduction number of channel up to 15from 5, frequency points from 2 to 4. Old Chs. New Chs. FY-3A/B/ MWHS FY-3C/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5.0 150(V) 10 150.0 150(H) 183.31±1 11 12 183.31±1.8 183.31±3 13 14 183.31±4.5 183.31±7 15

Atmospheric Transmission at Microwave Wavelengths 118GHz 89GHz 183GHz 150GHz

MWHS Introduction MWHS instrument MWHS scan sequence 0º(Nadir) 90º 180±2º Hot Targets 270º 53.35º 287±2º Cold Space 306.65º earth scene accelerate MWHS instrument MWHS scan sequence nonlinearity Radiometer transfer function

Calibration process Calibration flow chart Quality control flow chart No lunar intrusion If a lunar intrusion

Band correction: Planck’s Law: Calibration flow chart Triangular function No lunar intrusion If a 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:

Data_QA_Scan_Flag: ABCDE A_Flag: 0—preprocess success! 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! moonAffect: 0—no lunar contamination! 1—lunar contamination! Geoqc: 00,01,02—Geolocation success! 11,12,13—Geolocation Failure! No lunar intrusion If a lunar intrusion Use to compute Then use to compute antenna brightness temperature. Compute scene TBs by antenna correction

FY-3D MWHSII Global Brightness Temperature（Ascending）

FY-3D 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 AGC adjustment Long-term trends of Warm Target view counts

MWHS Noise Equivalent Delta Temperature

Center Frequency（GHz） Inter-satellite Validation of Observation FY-3D MWHS VS. Soumi/NPP ATMS Corresponding channels between FY-3D MWHS and Soumi/NPP ATMS Data : 2017.12.21-2017.12.30 Key match-up conditions Difference of observing times < 20 minutes Difference of satellite zenith angles < 5° Distance < 3 km Uniformity check : STD (3×3 pixels BT) < 1 K Center Frequency（GHz） MWHS Channel ATMS Channel 89.0/88.2 1 -- 118.750.08 2 118.750.2 3 118.750.3 4 118.750.8 5 118.751.1 6 118.752.5 7 118.753.0 8 118.755.0 9 150.0/165.5 10 183.31±1 11 22 183.31±1.8 12 21 183.31±3 13 20 183.31±4.5 14 19 183.31±7 15 18

Inter-satellite Validation of Observation Ch.11 Ch.12 Ch.13 Ch.14 Ch.15 Brightness Temperature of MWHS versus that of ATMS

SUMMARY FY-3D MWHS(II) on-orbit calibration system has been working well, and the basic calibration data are stable. The Noise Equivalent Delta Temperature of FY-3D MWHS(II) is well characterized and meets the specification. Assessments of FY-3D MWHS(II) performance will using NWP O-B and site calibration test data.

Thank you!