All-Sky Assimilation of GOES-16 Water Vapor Channels with Accounting Cloud-Dependent Variations of Inter-Channel Correlations

The advanced baseline imager (ABI) onboard GOES-16 has three water vapor channels (8, 9, 10) designed to sample high-, mid-, and low-level tropospheric water vapor. This study explores the methods of all-sky assimilation of the brightness temperatures (BTs) from all three GOES-16 water vapor channels for improving numerical simulations of hurricanes. The NASA unified Weather Research and Forecasting (NU-WRF) model and the National Centers for Environmental Prediction (NCEP) Gridpoint Statistical Interpolation (GSI)-based three-dimensional ensemble-variational hybrid data assimilation (3DEnVAR) system are applied.

We first examine the inter-channel correlations among the all-sky BTs from the three water vapor channels. Our findings reveal that these inter-channel correlations exhibit cloud-dependent features. Considering the distinct characteristics of the inter-channel correlations, we conducted sensitivity experiments for Hurricane Laura (2020) with various configurations of assimilating the all-sky BTs from the three water vapor channels. The experiment employing the optimal bias correction (BC) scheme and data assimilation configuration, as cited in Feng and Pu (2022, Mon. Wea. Rev.), serves as our baseline. The outcomes underscore the criticality of addressing inter-channel correlations during the assimilation of all-sky BTs from GOES-16's water vapor channels.