Progress in the study of the Chinese Reference Ionosphere

Principal features of the Chinese Reference Ionosphere(CRI) are described in brief with an emphasis on its difference from the IRI. The CRI improvements include a model for the F2-layer prediction for use in the Asia-Oceania Region(known as the AOR mapping) replacing the CCIR or URSI coefficients in the IRI-90, a model of the F1-layer occurrence for use in China removing the restriction of the F1-layer occurrence in winter, and a new E-layer peak height hmE = 115 km instead of 105 km in the IRI-90.