Autoregressive Prediction Method of E_10.7 Index

In response to the demand for the new solar ultraviolet radiation index E_10.7 in the operation of upper atmospheric density prediction and orbit prediction, this paper carries out the research on E_10.7 index inversion and medium-term prediction based on the integrated solar irradiance from 0.1 to 105 nm provided by TIMED-SEE instrument. The E_10.7 index is the radiation flux in the solar spectrum at wavelengths from 0.1 to 105 nm in the same unit as the F_10.7 index (sfu, 1 sfu = 10^–22 W·m^–2·Hz^–1). The integrated solar irradiance from 0.1 to 105 nm provided by the TIMED-SEE instrument has the advantages of high time resolution, short delay time, and easy availability. The quasi-real-time E_10.7 can be retrieved by least square fitting, and the root mean square error is 5.445 sfu. The average relative error of the next 27 days prediction is 7.83% using the autoregressive model. Using the same method, the 27 days prediction test of the 81-day central moving average of E_10.7 is also carried out. The average relative error of the next 27-day predictions of the 81-day central moving average of E_10.7 is 3.63%.