A Study of Accuracy of Brightness Temperature and Retrieval Products From Ground-based Microwave Radiometer

Abstract

Ground-based microwave radiometer (MWR) utilizes in this study is RPG-HTAPRO-G3, which measures the atmospheric radiation characteristics at 7 oxygen channels and 7 water vapor channels to obtain atmospheric thermodynamic profiles. The reliability of 14 channels brightness temperature (BT)from MWR is tested by contrasting the BTs simulated by the monochromatic radiative transfer model MonoRTM in Linux with that observed by MWR. The results show that BTs of oxygen channels have better correlation and consistency than BTs of water vapor channels. The correlation coefficients are 0.99 and 0.92 respectively. By comparing the mean bias (MB) and root-mean-square error (RMSE) of retrieval products from MWR and L-band radiosonde in different height of non-rainy day, temperature below 4000m is generally more accurate than in other height, the value of MB of temperature is -1.5-1.0.The difference of MB and RMSE of water vapor density is small and consistent. The MB value of water vapor density is positive. The RMSE of water vapor density (0-0.6 g/m3) decreases with height. The MB and RMSE of relative humidity are higher than temperature and water vapor density obviously. Atmospheric instability indices, such like K Index (KI), Lifting Index (LI), Showalter Index (SI), Total Total Index (TTI) and Convective Available Potential Energy (CAPE) derived from MWR are examined by the L-band radiosonde data in one year. The results show that correlation coefficients of 5 instability indices are 0.72, 0.93 0.86,0.76 and0.62.