| Abstract: |
Joint Polar Satellite System-1 (JPSS-1) as the heritage of Suomi Nation Polar-orbiting Partnership (SNPP) satellite continues to have the Advanced Technology Microwave Sounder (ATMS) onboard. After the successful launch of JPSS-1, ATMS on-orbit performance will also be characterized using the Global Positioning Satellite (GPS) radio occultation (RO) data as input to the U.S. Joint Center of Satellite Data Assimilation community radiative transfer model (CRTM). GPS RO raw data are SI traceable, have high accuracy and precision, high vertical resolution, no calibration needed, no contamination from clouds and no instrument drift. Such unique features of GPS RO data enable an accurate estimation of ATMS bias of upper troposphere and lower stratosphere temperature sounding channels. Previously, the absolute accuracy of antenna brightness temperatures (TDR) from SNPP ATMS has been quantified using the U.S and Taiwan joint Constellation Observing System for Meteorology, Ionosphere, and Climate/Formosa Satellite Mission 3 (COSMIC/FORMOSAT3) RO data, and it is found that the mean differences (e.g., biases) of observed TDR observations to RO simulations are positive for channels 6, 10–13 with values smaller than 0.5 K and negative for channels 5, 7–9 with values greater than −0.7 K. The bias distribution is slightly asymmetric across the scan line. After the bias removal in ATMS TDR data, it is shown that the distribution of residual errors for ATMS channels 5–13 is close to a normal Gaussian one. Thus, for these channels, the ATMS antenna brightness temperature can be absolutely calibrated to the sensor brightness temperature without a systematic bias. In the present study, besides from COSMIC/FORMOSAT3, RO data from (Korean Multi-Purpose Satellite-5 (KOMPSAT5) and Global Navigation Satellite System (GNSS) Receiver for Atmospheric Sounding (GRAS) onboard European Meteorological Operational (MetOp) satellites will be incorporated for getting more statistically significant bias characterization for JPSS-1 ATMS upper level temperature sounding channels. Meanwhile, the scan-angle and latitude-dependence of the bias will be analyzed. Furthermore, the bias of upper level temperature channel bias from JPSS-1 ATMS will be compared with that from SNPP to evaluate the performance of JPSS-1. |
