A Comparative Study on Wet Atmospheric Profiles Using KOMPSAT-5 and COSMIC Radio Occultation Data over Indian Region

Abstract

A comparative assessment of wet atmospheric profiles is conducted using data from the Korea Multi-Purpose Satellite-5 (KOMPSAT-5) and the Constellation Observing System for Meteorology, Ionosphere, and Climate(COSMIC) radio occultation (RO) to validate the KOMPSAT-5 profiles over the Indian region. KOMPSAT-5 and COSMIC wet atmospheric profiles for the year 2019 are compared, providing 29 overlapping locations that satisfy the spatial and temporal matching criteria of a 3° grid and a 3-hour window, respectively, from the surface up to 40 km altitude. The results show that the mean differences in pressure, temperature, vapour pressure, and refractivity are 0.16 hPa, 0.17 °C, -0.03 hPa, and -0.097, respectively. A relatively large temperature mean difference of nearly 3 °C is found over sea surface locations in the southern Indian region and at a location in western India. In contrast, the mean pressure difference is observed to be around 2 hPa at a location in eastern India. Vertically averaged mean differences and root mean square errors (RMSEs) for different altitude intervals from the surface to 20 km are also calculated and discussed in detail. These show greater variations in pressure, vapour pressure, and refractivity at lower altitudes, while temperature differences are more pronounced at higher altitudes. Validation of KOMPSAT-5 temperature and pressure profiles with radiosonde observations is also carried out, showing mean errors of less than 1 °C and 1 hPa, respectively. From the analysis, it is concluded that KOMPSAT-5 profiles closely match both COSMIC and radiosonde profiles and can be reliably used along with other RO datasets for various atmospheric studies over this region