Fy-3a Weather Satellite Infrared Spectrometer Transmission Rate And Atmospheric Parameters Simulated Inversion Test

FY-3 meteorological satellite is the second generation of polar-orbit meteorological satellite in China, it will carry InfRared Atmospheric Sounder (IRAS)? Microwave Atmospheric Sounder, Microwave Atmospheric Humidity Sounder for the first time. In order to provide some helpful information to the IRAS' manufacturer, much simulation should be done to verify the characteristics of IRAS so that the satellite can be in good working state and the satellite data can be useful.This paper bases on the characteristics and spectral response function of the primary ERAS sounding channels and GENLN2 line-by-line spectral transmittance database, calculates the fast radiative transfer model's (RTTOV7) transmittance coefficients and verify them. We also calculate some atmospheric profiles' channel transmittance and weighting function as well as the simulating satellite observed radiance then compare the results with High Resolution Infrared Sounder (HIRS).It shows that the IRAS' transmittance coefficients is satisfying, the channel transmittance and weighting function curves are reasonable, they have little differences from that of HIRS, can indicate the contribution of each atmospheric layer make to the upwelling radiance from the whole atmosphere. The levels of peak energy contribution were mostly consistent with the prepositional target, although some channels'peak-levels are a little raised from the design object; the variety trend is consistent with HIRS/3 instrument. IRAS' simulating channel observed radiance also has little differences from that of HIRS and it can be used in the temperature profile retrieval.Under the calculation results of IRAS' channel transmittance, the paper performs sensitivity tests of temperature profile retrieval. These tests are about how do different channel groups; different guess profile and different instrument noise influence the temperature profile retrieval. Through the results we know the IRAS' invert precision is associated with the peak-levels of the transmittance weighting function. The designed noises can be used to retrieve temperature profile, but if it is enlarged the invert precision will be reduced. As a whole, the ability of temperature profile retrieval from ERAS' simulated measurement is acceptable.