Ionospheric electron density observed by FORMOSAT-3/COSMIC over the European region and validated by ionosonde data

This research is motivated by the recent IGS Ionosphere Working Group recommendation issued at the IGS 2010 Workshop held in Newcastle, UK. This recommendation encourages studies on the evaluation of the application of COSMIC radio occultation profiles for additional IGS global ionosphere map (GIM) validation. This is because the reliability of GIMs is crucial to many geodetic applications. On the other hand, radio occultation using GPS signals has been proven to be a promising technique to retrieve accurate profiles of the ionospheric electron density with high vertical resolution on a global scale. However, systematic validation work is still needed before using this powerful technique for sounding the ionosphere on a routine basis. In this paper, we analyze the properties of the ionospheric electron density profiling retrieved from COSMIC radio occultation measurements. A comparison of radio occultation data with ground-based measurements indicates that COSMIC profiles are usually in good agreement with ionosonde profiles, both in the F2 layer peak electron density and the bottom side of the profiles. For this comparison, ionograms recorded by European ionospheric stations (DIAS network) in 2008 were used.

[1]  S. Syndergaard,et al.  Preparing for COSMIC: Inversion and Analysis of Ionospheric Data Products , 2006 .

[2]  F. T. Berkey,et al.  Comparisons of GPS/MET retrieved ionospheric electron density and ground based ionosonde data , 2001 .

[3]  Chien-Hung Lin,et al.  Global ionospheric structure imaged by FORMOSAT-3/COSMIC: Early results , 2009 .

[4]  Bodo W. Reinisch,et al.  Deducing topside profiles and total electron content from bottomside ionograms , 2001 .

[5]  Iwona Stanislawska,et al.  DIAS Project: The establishment of a European digital upper atmosphere server , 2005 .

[6]  Chao-Han Liu,et al.  Profiling of Ionospheric Electron Density Based on FormoSat-3/COSMIC Data: Results from the Intense Observation Period Experiment , 2009 .

[7]  Ying-Hwa Kuo,et al.  Comparison of COSMIC ionospheric measurements with ground-based observations and model predictions : Preliminary results , 2007 .

[8]  U. Foelsche,et al.  Atmosphere and climate : studies by occultation methods , 2006 .

[9]  Christian Rocken,et al.  Analysis and validation of GPS/MET radio occultation data in the ionosphere , 1999 .

[10]  W. Wan,et al.  Statistical analysis on spatial correlation of ionospheric day-to-day variability by using GPS and Incoherent Scatter Radar observations , 2007 .

[11]  Xiong Hu,et al.  Analysis of inversion errors of ionospheric radio occultation , 2009 .

[12]  T. Fang,et al.  Motions of the equatorial ionization anomaly crests imaged by FORMOSAT‐3/COSMIC , 2007 .

[13]  L. Grunwaldt,et al.  GPS radio occultation measurements of the ionosphere from CHAMP: Early results , 2002 .

[14]  Norbert Jakowski.  Ionospheric GPS radio occultation measurements on board CHAMP , 2005 .

[15]  Ya Liou.  Radio Occultation Method for Remote Sensing of the Atmosphere and Ionosphere , 2010 .

[16]  Larry J. Romans,et al.  Ionospheric electron density profiles obtained with the Global Positioning System: Results from the GPS/MET experiment , 1998 .

[17]  Gottfried Kirchengast,et al.  Occultations for Probing Atmosphere and Climate , 2004 .

[18]  Jaume Sanz,et al.  Improving the Abel inversion by adding ground GPS data to LEO radio occultations in ionospheric sounding , 2000 .

[19]  Toshitaka Tsuda,et al.  Three‐dimensional estimation of electron density over Japan using the GEONET GPS network combined with SAC‐C data and ionosonde measurements , 2005 .

[20]  Christian Rocken,et al.  Inversion and error estimation of GPS radio occultation Data , 2004 .

[21]  Libo Liu,et al.  Seasonal variations of the ionospheric electron densities retrieved from Constellation Observing System for Meteorology, Ionosphere, and Climate mission radio occultation measurements , 2009 .

[22]  Xinan Yue,et al.  Error analysis of Abel retrieved electron density profiles from radio occultation measurements , 2010 .

[23]  F. R. Colomb,et al.  SAC-C mission, an example of international cooperation , 2002 .

[24]  Jaume Sanz,et al.  Improvement of ionospheric electron density estimation with GPSMET occultations using Abel inversion and VTEC information , 2003 .

[25]  J. Klobuchar,et al.  Eye on the Ionosphere: The Spatial Variability of Ionospheric Range Delay , 2000, GPS Solutions.

[26]  J. Wickert,et al.  GPS radio occultation with GRACE: Atmospheric profiling utilizing the zero difference technique , 2004, physics/0409032.

[27]  Bodo W. Reinisch,et al.  Recent advances in real-time analysis of ionograms and ionospheric drift measurements with digisondes , 2005 .

[28]  P. R. Straus,et al.  GPS occultation sensor observations of ionospheric scintillation , 2003 .

[29]  K. Igarashi,et al.  Structure of the Earth's lower ionosphere observed by GPS/MET radio occultation , 2002 .

[30]  Grzegorz Michalak,et al.  GPS radio occultation: results from CHAMP, GRACE and FORMOSAT-3/COSMIC. , 2009 .

[31]  Leo F. McNamara,et al.  Quality figures and error bars for autoscaled Digisonde vertical incidence ionograms , 2006 .