Progress in the study of the Chinese Reference Ionosphere

Wu, Jian; Quan, Katie; Dai, Kailiang; Luo, F.-G.; Sun, Xiaojing; Li, Z.-Q.; Cao, Chong; Liu, R.-Y.; Shen, Ching

doi:10.1016/0273-1177(95)00921-3

Cited by 11 publications

(8 citation statements)

References 6 publications

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“…This is understood because of the limitation of global empirical models and rather complicated nature of the ionosphere. Besides, IRI does not include Chinese data, and this will result in no good agreement between observed and predicted values in China (Huang et al, 1995;Wu et al, 1996). Titheridge's model has a relatively larger difference than ours.…”

Section: Comparison With Iri and Titheridge's Modelmentioning

confidence: 64%

“…Based on long time series of ionospheric parameters over Wuhan, Liu et al (2004) constructed single-station models of f oF2 using Fourier expansion and cubic-B splines approaches. Chen et al (2004) Wu et al (1996) developed a revised regional model called the Chinese Reference Ionosphere (CRI) and it is more accurate than the IRI for use in and around China. However the CRI did not modify the E-layer critical frequency and the data used by CRI did not include the ionosonde data of Wuhan.…”

Section: Introductionmentioning

confidence: 99%

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An empirical model of ionospheric foE over Wuhan

et al. 2006

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Daytime half-hourly values of the critical frequency of the ionospheric E-layer, f oE, obtained at Wuhan Ionospheric Observatory (geographic 114.4• E, 30.6 • N; 45.2 • dip), China, during the whole interval of 1957-1991 and 1999-2004 have been used to develop an empirical model. The model, including variations with local time, day number and solar cycle, is in agreement with the observations. A comparison between our model and IRI and Titheridge's model has also been made. Statistically, our model gives a better performance than IRI and Titheridge's model because data set is obtained with our own station. Both the IRI and Titheridge's model overestimate f oE especially in May to September months. Combing with past investigations, we suggest that overestimation of ionospheric parameters by IRI may be a common feature in East Asia. This result is very helpful for both the correction of IRI in East Asia and the development of Chinese Reference Ionosphere (CRI) model.

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Section: Comparison With Iri and Titheridge's Modelmentioning

confidence: 64%

Section: Introductionmentioning

confidence: 99%

An empirical model of ionospheric foE over Wuhan

et al. 2006

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“…This is to be expected since our model is based on nine years of data from this region while none of these data were used in the development of IRI. Actually, only very few ionosonde data from the Chinese subcontinent were used for IRI [ Wu et al , 1996; Liu et al , 2004].…”

Section: Validationmentioning

confidence: 99%

An empirical orthogonal function model of total electron content over China

et al. 2008

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[1] In this paper a climatology model of total electron content (TEC) over China has been developed on the basis of the empirical orthogonal function (EOF) analysis using Global Positioning System (GPS) data from the International Global Navigation Satellite System Service (IGS) and Crust Movement Observation Network of China (CMONOC) covering almost the whole Chinese sector during 1996-2004. The model well represents observational data with mean bias of À0.00994 TECU (1 TECU = 1.0 Â 10 16 elÁ m À2 ) and standard deviation of 5.42 TECU. Then the EOF model and IRI have been used in three-dimensional variational (3DVAR) data assimilation experiments separately, and results reveal that the ability of assimilation nowcasting for the EOF model is better as it provides a more authentic background.

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“…On the other hand, the development of the regional ionospheric models with higher resolution and accuracy is of great importance to investigate the local characteristics of the ionosphere. For instance, Wu et al [] provided a Chinese Reference Ionosphere (CRI) using ionospheric observations at 39 ionosonde stations in the region of Asia and Oceania during 1940–1972. Considerable improvements were made, and the resulted CRI is more accurate than the IRI model in and around China.…”

Section: Introductionmentioning

confidence: 99%

Modeling Chinese ionospheric layer parameters based on EOF analysis

Wan

Xiong

et al. 2015

Space Weather

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Using 24-ionosonde observations in and around China during the 20th solar cycle, an assimilative model is constructed to map the ionospheric layer parameters (f o F 2 , h m F 2 , M(3000)F 2 , and f o E) over China based on empirical orthogonal function (EOF) analysis. First, we decompose the background maps from the International Reference Ionosphere model 2007 (IRI-07) into different EOF modes. The obtained EOF modes consist of two factors: the EOF patterns and the corresponding EOF amplitudes. These two factors individually reflect the spatial distributions (e.g., the latitudinal dependence such as the equatorial ionization anomaly structure and the longitude structure with east-west difference) and temporal variations on different time scales (e.g., solar cycle, annual, semiannual, and diurnal variations) of the layer parameters. Then, the EOF patterns and long-term observations of ionosondes are assimilated to get the observed EOF amplitudes, which are further used to construct the Chinese Ionospheric Maps (CIMs) of the layer parameters. In contrast with the IRI-07 model, the mapped CIMs successfully capture the inherent temporal and spatial variations of the ionospheric layer parameters. Finally, comparison of the modeled (EOF and IRI-07 model) and observed values reveals that the EOF model reproduces the observation with smaller root-mean-square errors and higher linear correlation coefficients. In addition, IRI discrepancy at the low latitude especially for f o F 2 is effectively removed by EOF model.

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Progress in the study of the Chinese Reference Ionosphere

Cited by 11 publications

References 6 publications

An empirical model of ionospheric foE over Wuhan

An empirical model of ionospheric foE over Wuhan

An empirical orthogonal function model of total electron content over China

Modeling Chinese ionospheric layer parameters based on EOF analysis

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