Assimilation of Ionosphere Observations in the Whole Atmosphere Community Climate Model with thermosphere-ionosphere eXtension

The impact of assimilating Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) electron density profiles and ground-based Global Navigation Satellite System (GNSS) total electron content (TEC) observations in a whole atmosphere data assimilation system is investigated through a series of data assimilation experiments. The experiments are performed using the Whole Atmosphere Community Climate Model with thermosphere-ionosphere eXtension (WACCMX) with data assimilation provided by the Data Assimilation Research Testbed (DART) ensemble adjustment Kalman filter. Results from Observing System Simulation Experiments (OSSEs) demonstrate that the assimilation of ionosphere observations improves the short-term (1 hr) forecasts and analyses. The OSSEs show that the short-term forecasts and analyses are further improved when the ionosphere observations adjust the thermosphere neutral composition and temperature in addition to the ionosphere electron density. Based on an initialized forecast experiment, we find that adjusting the thermosphere neutral composition and temperature also leads to improved forecast skill in the ionosphere on longer time scales (i.e., beyond 1 hr). Results exploring the impact of assimilating ionosphere observations during the 2009 sudden stratosphere warming time period will also be presented. These initial results represent the first whole atmosphere data assimilation system with capabilities to assimilate observations from the troposphere to the ionosphere-thermosphere.