Abstract The ionospheric variabilities are influenced by various drivers, and quantifying their relative contributions is beneficial to ionospheric modeling and ionospheric forecasting, but this is still a significant challenge in the ionospheric community. In present paper, the global ionosphere maps, solar indices, solar wind and interplanetary parameters, geomagnetic indices, and lower atmospheric parameters from 2001 to 2021 are collected, and the Liang‐Kleeman information flow is used to measure the amount of information exchanges from external drivers to ionospheric TEC at different geographical regions, and the normalized Liang‐Kleeman information flow is adopted to quantify their relative information contributions. The results show that the geographical distribution of information flow has prominent hemispheric asymmetry, and overall, the information flows from solar indices (solar wind and interplanetary parameters, geomagnetic indices) to ionospheric TEC in the northern hemisphere are larger than those in the southern hemisphere. Ionospheric self‐influence (i.e., internal processes of the ionosphere) has the largest information contribution to ionospheric TEC, accounting for about 46.78. Solar activity manifested as P index has the second largest contribution (nearly 35.29). Solar wind and interplanetary activity represented as IMF magnitude contributes around 2.94, geomagnetic activity characterized as ASYH index accounts for about 1.52, lower atmospheric forcing contributes nearly 7.75, and noise accounts for approximately 5.73. What's more, the performances of the IRI‐2020 model are evaluated from the perspective of information flow.
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