The Thermosphere Was Poorly Predictable Not Only During but Also Before and After the Starlink Storm on 3–4 February 2022

Observation-based simulations of the ionosphere were performed with the NRLMSISE-00 model for six locations around the globe during 1–9 February 2022, which includes the so-called Starlink Storm. Unlike other studies, we focused on the magnetically quiet days around the storm. Unexpectedly, the observed values of the F2-layer peak density were ∼50% larger than the simulated values. We show that this implies that the daytime O density in the thermosphere was systematically ∼30% larger than the NRLMSISE-00 predicts. Further investigation shows that this discrepancy is not an exclusive feature of the period around the Starlink Storm and a similar problem happens for some periods for different years. It is unclear if the reason is an actual increase of the O density or its underestimation by the model. Resolving this problem is critical for providing accurate predictions of the atmosphere to avoid the degradation of normal operation or even loss of space assets.