Developing a GOLD Observation Operator for JEDI-based Data Assimilation into WACCM-X

The growing number of Low Earth Orbit (LEO) satellites raises collision risks in that region. To avoid these collisions, satellite operators need accurate predictions of drag caused by the neutral density. However, reliable forecasting of space weather, including this drag, in the geospace environment is quite challenging, as the upper atmosphere is a highly driven, non-linear system over an immense scale. Predictions based solely on physics-based or empirical models quickly diverge from reality, particularly in geomagnetic storm conditions. To address this, data assimilation (DA) techniques integrate observations, model predictions, and their uncertainties to improve state estimations and improve forecast accuracy and lead times.
One of the most crucial elements of DA for space weather forecasting of the orbital environment is thermospheric observations. NASA’s GOLD mission provides integrated thermospheric temperature observations which have been shown to improve model thermosphere ionosphere states in the Data Assimilation Research Testbed (DART) research framework [Laskar, 2021]. We are extending this work to add GOLD temperature and composition measurements to the operationally focused JEDI (Joint Effort for DA Integration) framework developed with support from NASA, NOAA, and the Department of Defense (DOD). This will allow the community to utilize the GOLD observations with both a broader range of DA methods available in JEDI, such as variational and hybrid ensemble, as well as to more easily transition the methods to operational forecasting centers. We also investigate the uncertainty of these observations for better integration into the various DA methods under development.

Laskar, F. I., et al. “Impact of GOLD retrieved thermospheric temperatures on a whole atmosphere data assimilation model.” Journal of Geophysical Research: Space Physics, vol. 126, no. 1, Jan. 2021, https://doi.org/10.1029/2020ja028646