Ionospheric behavior of the F2 peak parameters foF2 and hmF2 at Hainan and comparisons with IRI model predictions
作者单位：Division of Geomagnetism and Space PhysicsInstitute of Geology and GeophysicsChinese Academy of Sciences
会议名称：《中国科学院地质与地球物理研究所2007学术年会》
会议日期：2008年
学科分类：070802[理学-空间物理学] 07[理学] 0708[理学-地球物理学]
基 金：supported by the National Natural Science Foundation of China(40636032) the KIP Pilot Project(kzcx3-sw-144) of Chinese Academy of Sciences National Important Basic Research Project (2006CB806306)
关 键 词：Low latitude ionosphere F2 peak parameters IRI model
摘 要：Monthly median values of foF2,hmF2 and M(3000)F2 parameters,with hourly time interval resolution for the diurnal variation, obtained with DPS-4 digisonde observations at Hainan(19.4°N,109.0°E) are used to study the low latitude ionospheric variation behavior. The observational results are compared with the International Reference Ionospheric Model(IRI) *** time period coverage of the data used for the present study is from March 2002 to February *** present study showed that:(1) In general,IRI predictions using CCIR and URSI coefficients follow well the diurnal and seasonal variation patterns of the experimental values of foF2. However,CCIR foF2 and URSI foF2 IRI predictions systematically underestimate the observed results during most time period of the day,with the percentage differenceΔfoF2(%) values changing between about -5%and -25%,whereas for a few hours around pre-sunrise, the IRI predictions generally overestimate the observational ones withΔfoF2(%) sometimes reaching as large as～30%.The agreement between the IRI results and the observational ones is better for the year 2002 than for the other *** best agreement between the IRI results and the observational ones is obtained in summer when using URSI coefficients,with the seasonal average values ofΔfoF2(%) being within the limits of±10%.(2) In general,the IRI predicted hmF2 values using CCIR M(3000)F2 option shows a poor agreement with the observational ***,when using the measured M(3000)F2 as input,the diurnal variation pattern of hmF2 given by IRI2001 has a much better agreement with the observational one with the detailed fine structures including the pre-sunrise and post-sunset peaks reproduced reasonably *** agreement between the IRI predicted hmF2 values using CCIR M(30,000)F2 option and the observational ones is worst for the afternoon to post-midnight hours for the high solar activity year *** daytime hours the agreement between the hmF2 values obtained