Evaluation of FY-3E/HIRAS-II Radiometric Calibration Accuracy Based on OMB Analysis

Abstract

Before infrared hyperspectral data are used in satellite data assimilation systems or retrieval systems, the quantitative analysis of data deviation is necessary. Based on RTTOV’s (Radiative Transfer for TOVS) simulation data of FY-3E/HIRAS-II (Hyperspectral Infrared Atmospheric Sounder) and the observation data of HIRAS-II, we counted the bias of observation minus simulation (OMB) during an on-orbit test; analyzed the characteristics and reasons for the bias from the perspective of the FOV (field of view), the scanning angle of the instrument, the day and night, and the target temperature change; and analyzed the stability of the radiometric calibration accuracy. We also combined the results of the MetOp-C/IASI (infrared atmospheric sounding interferometer), a similar high-precision instrument, with the bias of OMB to compare and evaluate the FY-3E/HIRAS-II radiometric calibration accuracy. In the end, we found that the mean OMB bias of the long-wave and medium-wave infrared bands is within ±2 K, and the bias standard deviation is better than 2 K; the bias of each FOV is consistent and the bias of most channels is better than 2 K. The OMB bias of each channel is consistent with the changes in the angle of the instrument. The bias trend of long-wave and medium-wave infrared channels is more consistent with the deviation of the day and night; the bias of the short-wave infrared channel at night is lower than in the daytime. When counting the bias as the target temperature changed, the results showed that there are no obvious temperature dependencies in the long-wave and medium-wave infrared channels. This reflects that the instrument’s non-linear effect is well ordered. We further evaluated the stability of the radiometric calibration accuracy through statistics from the OMB standard deviation of each channel of FY-3E/HIRAS-II. Most channel accuracy stability values were better than 0.1 K. We calculated that IASI and HIRAS-II OMB have double differences, and the results show that the double difference in most channels is better than 1 K. It shows that the HIRAS-II and IASI observations are highly consistent. Through the statistics of the OMB bias during the on-orbit test period of FY-3E/HIRAS-II, we fully evaluated its radiometric calibration accuracy and laid the foundation for FY-3E/HIRAS-II data to be used in the retrieval application and assimilation system.

First PWV Retrieval Using MERSI‐LL Onboard FY‐3E and Cross Validation With Co‐Platform Occultation and Ground GNSS

“…(2022) and P. Zhang et al. (2022). The GNSS troposphere products are available from the NGL (http://geodesy.unr.edu/gps_timeseries/trop/), with the details of data shown in Yuan et al.…”

“…As one of the representatives, Fengyun 3E (FY‐3E), the world's first early morning (EM) orbit meteorological remote sensing satellite for civil use, was launched on 5 July 2021 (Shao, 2022; P. Zhang et al., 2024). The primary goal of the FY‐3E mission, equipped with 11 scientific instruments, is to provide global numerical weather prediction (NWP) models with infrared (IR) and microwave soundings (C. Zhang et al., 2022; P. Zhang et al., 2022). Scholars have conducted extensive research on these 11 onboard sensors.…”

“…C. Zhang et al. (2022) and P. Zhang et al. (2022) evaluated the radiometric calibration accuracy of the Hyperspectral Infrared Atmospheric Sounder‐II (HIRAS‐II) and found that the Mean Bias of the long‐wave and medium‐wave infrared bands is within 2 K. Preliminary on‐orbit test results of the Medium‐Energy Electron Detector, an instrument of Space Environment Monitor‐II (SEM‐II) on the FY‐3E, were made by Ye et al.…”

Retrieving Atmospheric Gas Profiles Using FY-3E/HIRAS-II Infrared Hyperspectral Data by Neural Network Approach

“…Each detector array contains 9 detector bands that observe the target region simultaneously. Furthermore, each probe element has an opening angle of 1 • , corresponding to an instantaneous field of view of each probe unit to be about 14 km at its lowest point [41][42][43]. The training set labels were determined based on selected gas datasets in this experiment.…”

Impacts of Direct Assimilation of the FY-4A/GIIRS Long-Wave Temperature Sounding Channel Data on Forecasting Typhoon In-Fa (2021)

“…Hyperspectral infrared sounders can measure radiation in thousands of spectrally narrow bands, which can provide atmospheric temperature and water vapor information, as well as other atmospheric compositions, with higher accuracy and vertical resolution than previous low-spectral-resolution infrared sounders such as the High Resolution Infrared Sounder (HIRS). Since the 2000s, several hyperspectral infrared sounders onboard polar-orbiting satellites have been developed, including the Atmospheric Infrared Sounder (AIRS) onboard the National Aeronautics and Space Administration (NASA) Earth Observing System (EOS) polar-orbiting Aqua platform [6,7], the Infrared Atmospheric Sounder Interferometer (IASI) onboard the European Meteorological Operational satellites [8], the Cross-track Infrared Sounder (CrIS) onboard the Suomi National Polar-Orbiting Partnership (Suomi NPP) and National Oceanic and Atmospheric Administration (NOAA-20) satellites [9], and the Hyperspectral Infrared Atmospheric Sounder (HIRAS) onboard the Chinese polar-orbiting satellites FY-3D and FY-3E [10,11]. The observations from these sounders have been widely assimilated into global and regional NWP models.…”