Analysis of slant path simulation effect for the all-sky using 1DVAR system

The theoretically calculated radiance plays a crucial role in numerical weather prediction models. Therefore, improving the accuracy of radiative transfer models is essential for precise radiance calculations. This study aims to enhance the accuracy of radiative transfer models by utilizing atmospheric profiles along the satellite-observed slant path rather than the vertical path. This approach is expected to improve the retrieval of temperature and humidity profiles, which are critical for accurate weather predictions. Previous research has shown that slant-path simulations significantly impact regions with high atmospheric variability and large viewing angles, improving RMSD in temperature and wind forecasts by 2-3% in the stratosphere and high latitudes9 This study extends these evaluations to all-sky conditions, considering the parallax effect of clouds for more accurate radiance calculations (B). The findings are expected to enhance weather prediction models by incorporating slant-path radiative transfer simulations.