Review of “Improvements to Predictions of the Ionospheric Annual Anomaly by the International Reference Ionosphere Model”

This study uses a newly conceived method of calculating hemispheric adjustments to the IRI URSI foF2 maps to investigate the model's capacity to represent the Annual Anomaly.The authors illustrate that the IRI performs better at reproducing this anomaly when using hemispheric indices versus using a single ionospheric adjustment index (IG).I have a few concerns regarding the concept of this study.The method used here to improve the IRI is essentially a two-pixel assimilation scheme (one for each hemisphere).It is hardly a question that such a scheme would improve the model's capacity to represent an anomaly that depends on the differential behaviour of the two hemispheres, especially when the stations you assimilated (i.e.used to develop IGNS) are the same ones being used to evaluate this phenomenon.The authors argue