Extended Impact of Global Hawk Dropsonde Observations for Four Tropical Cyclone Cases in 2016

In prior studies, the value of Global Hawk (GH) dropsonde observations on tropical cyclone analysis and prediction has proven beneficial. Current research is underway to expand the number of case studies over the period 2012-2017 to provide a comprehensive evaluation of the GH platform. In this work, we show initial work evaluating the impact of GH dropsondes for all 2016 tropical cyclone cases. Storms examined in this study include Gaston, Hermine, Matthew, and Karl. Global control and denial experiments were conducted at the Environmental Modeling Center (EMC) using the Finite-Volume on a Cubed-Sphere Global Prediction System (FV3GFS), which was implemented in operations on 12 June 2019. The code used was from October 2018, an earlier version of the FV3GFS. More experiments will be carried out using code from the operational version. Regional simulations are then performed using the global boundary conditions (control and denial) for the operational Hurricane Weather Research and Forecasting (HWRF) model. In addition to the track and intensity errors, the impacts are stratified by the sampling strategy (upstream versus inner-core environment) and the unique value of GH upper-level observations. Spatial and vertical impacts are examined to understand the assimilation impacts.