COMPARISON SIMULATED BRIGHTNESS TEMPERATURE BY RTTOV-11 WITH THE MEASUREMENTS FROM MWHS-II ONBOARD FY-3C SATELLITE

The new generation Microwave Humidity Sounder (MWHS-II) is a fifteen-channel microwave radiometer working at central frequency of 89, 118.75, 150 and 183.31GHz onboard FengYun 3C satellite (FY-3C). This paper provides an extensive evaluation of the measurements of MWHS-II with the radiances simulated by atmospheric radiative transfer model RTTOV-11 using ECMWF ERA data in 0.75 degrees grid at 37 vertical levels during 1, Feb 2014 and 31, Dec 2014. Because the brightness temperature over ocean surface is more stable than that over land surface and the emissivity of ocean surface is more accurate than land surface's, only the clear sky data over ocean surface is used for analysis. The analysis was conducted by two part. One is a global comparison of the TB products [1] of MWHS-II with the simulations by RTTOV-11, and the other is analyzing the effects of in-orbit calibration method on TB combined prelaunch thermal vacuum calibration[1]. The results shows that the monthly STD of TB products minor simulations by RTTOV-11 (TB differences) kept stable during the period calculated. And the monthly STD of TB differences are very close to the calibration sensitivity. The monthly means of TB differences is more stable in the channel of 1 similar to 5 and 10 similar to 12. However in the channel of 7 similar to 9 and 13 similar to 15, the monthly means of TB differences is more stable in cases corrected by hot bias. The antenna pattern correction contributes to decrease variety range of monthly means of TB differences in the channel of 5 similar to 6 and 11 similar to 13. A further evaluation on the measurements is progressing.