摘要：This paper presents the various candidate models used in deriving the 9th generation IGRF. Based on notes submitted to the IAGA working group V-MOD with the Gauss coefficients, a brief description of the data used and the method of modelling for each of the candidate models is given. The six candidate models for epoch 1995.0 and the five for epoch 2000.0 are presented. Improvements gained by the new models are also discussed.
