Assimilation of ABI and GLM at High Temporal and Spatial Scales

The GOES-R series Advanced Baseline Imagery (ABI) provides higher temporal, spatial, and spectral resolution information than previous geostationary instruments, while Geostationary Lightning Mapper (GLM) adds new information from geostationary orbit about storm updraft strength. This study explores the utilization of these new capabilities through the assimilation of ABI and GLM information using nudging or direct insertion methods, similar to the radar initialization and cloud analysis utilized by the RAP and HRRR operational models. The ABI cloud top height product is used to control hydrometeors, and GLM or cloud-top cooling from ABI are used to force convection. The importance of temperature modifications with hydrometeor addition or removal is noted, while methods forcing convection that increase vertical velocity or apply latent heating are compared. Simulation and assimilation are tested at spatial (1-3 km) and temporal (1-5 min) scales appropriate for ABI and GLM using the WRF-ARW model. Assimilation at different time scales (e.g., 1-5 min to 1 h) is evaluated. This study also considers the utility of different GLM information, including the most basic flash locations, event locations, and flash area. Proper utilization requires the consideration of the strengths and weaknesses of the GLM information. The effects of cycling and/or continuous nudging on the analysis and short-term forecast are analyzed, including their effect on precipitation, temperature, humidity, and winds.