Data assimilation of ground GPS total electron content into a physics‐based ionospheric model by use of the Kalman filter

Hajj, G. A.; Wilson, Brian; Wang, C.; Pi, Xiaoqing; Rosen, I. G.

doi:10.1029/2002rs002859

Cited by 96 publications

(96 citation statements)

References 27 publications

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“…The collocation of six of the ten GPS receivers with ionosondes (MacDougall et al, 1995) will have an added advantage in the tomographic imaging of the electron density structures in the polar cap and the calibration of the GPS data. This configuration will allow us to perform more realistic 3-D tomographic inversions of the ionosphere using the Multi-Instrument Data Analysis System -MIDAS (Mitchell and Spencer, 2003) or the Global Assimilative Ionospheric Model -GAIM (Hajj et al, 2004) than tomographic reconstructions that rely on statistical ionospheric models.…”

Section: Instruments and Datamentioning

confidence: 99%

Climatology of GPS phase scintillation and HF radar backscatter for the high-latitude ionosphere under solar minimum conditions

et al. 2011

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Abstract. Maps of GPS phase scintillation at high latitudes have been constructed after the first two years of operation of the Canadian High Arctic Ionospheric Network (CHAIN) during the 2008-2009 solar minimum. CHAIN consists of ten dual-frequency receivers, configured to measure amplitude and phase scintillation from L1 GPS signals and ionospheric total electron content (TEC) from L1 and L2 GPS signals. Those ionospheric data have been mapped as a function of magnetic local time and geomagnetic latitude assuming ionospheric pierce points (IPPs) at 350 km. The mean TEC depletions are identified with the statistical high-latitude and mid-latitude troughs. Phase scintillation occurs predominantly in the nightside auroral oval and the ionospheric footprint of the cusp. The strongest phase scintillation is associated with auroral arc brightening and substorms or with perturbed cusp ionosphere. Auroral phase scintillation tends to be intermittent, localized and of short duration, while the dayside scintillation observed for individual satellites can stay continuously above a given threshold for several minutes and such scintillation patches persist over a large area of the cusp/cleft region sampled by different satellites for several hours. The seasonal variation of the phase scintillation occurrence also differs between the nightside auroral oval and the cusp. The auroral phase scintillation shows an expected semiannual oscillation with equinoctial maxima known to be associated with aurorae, while the cusp scintillation is dominated by an annual cycle maximizing in autumn-winter. These differences point to different irregularity production mechanisms: energetic electron precipitation into dynamic auroral arcs versus cusp ionospheric convection dynamics. Observations suggest anisotropy of scintillationcausing irregularities with stronger L-shell alignment of irregularities in the cusp while a significant component of Correspondence to: P. Prikryl (paul.prikryl@crc.gc.ca) field-aligned irregularities is found in the nightside auroral oval. Scintillation-causing irregularities can coexist with small-scale field-aligned irregularities resulting in HF radar backscatter. The statistical cusp and auroral oval are characterized by the occurrence of HF radar ionospheric backscatter and mean ground magnetic perturbations due to ionospheric currents.

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Section: Instruments and Datamentioning

confidence: 99%

Climatology of GPS phase scintillation and HF radar backscatter for the high-latitude ionosphere under solar minimum conditions

et al. 2011

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“…The drift measurements use the fixed transmitter frequency mode . The inclusion of CADIs in CHAIN will allow us to perform more realistic 3-D tomographic inversions of the ionosphere using the Multi-Instrument Data Analysis System -MIDAS (Mitchell and Spencer, 2003) or the Global Assimilative Ionospheric Model -GAIM (Hajj et al, 2004).…”

Section: Instrumentsmentioning

confidence: 99%

GPS TEC, scintillation and cycle slips observed at high latitudes during solar minimum

et al. 2010

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Abstract. High-latitude irregularities can impair the operation of GPS-based devices by causing fluctuations of GPS signal amplitude and phase, also known as scintillation. Severe scintillation events lead to losses of phase lock, which result in cycle slips. We have used data from the Canadian High Arctic Ionospheric Network (CHAIN) to measure amplitude and phase scintillation from L1 GPS signals and total electron content (TEC) from L1 and L2 GPS signals to study the relative role that various high-latitude irregularity generation mechanisms have in producing scintillation. In the first year of operation during the current solar minimum the amplitude scintillation has remained very low but events of strong phase scintillation have been observed. We have found, as expected, that auroral arc and substorm intensifications as well as cusp region dynamics are strong sources of phase scintillation and potential cycle slips. In addition, we have found clear seasonal and universal time dependencies of TEC and phase scintillation over the polar cap region. A comparison with radio instruments from the Canadian GeoSpace Monitoring (CGSM) network strongly suggests that the polar cap scintillation and TEC variations are associated with polar cap patches which we therefore infer to be main contributors to scintillation-causing irregularities in the polar cap.

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“…[3] Applications of the Kalman filter [Kalman, 1960;Kalman and Bucy, 1961] and its variants for assimilation of ionospheric observations to first principle ionospheric models have been shown to be effective [e.g., Schunk et al, 2004;Scherliess et al, 2006Scherliess et al, , 2009Hajj et al, 2004;Komjathy et al, 2010;Khattatov, 2010, and references therein]. On the other hand, thermospheric data assimilation applications have so far been limited largely by a lack of operational monitoring of thermospheric parameters.…”

Section: Introductionmentioning

confidence: 99%

Thermospheric mass density specification using an ensemble Kalman filter

2013

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[1] This paper presents an application of ensemble Kalman filtering (EnKF) to a general circulation model of the thermosphere and ionosphere. It is designed to incorporate the feedback between plasma and neutral variables in both the analysis and forecast steps of filtering so that thermospheric parameters can be inferred from ionospheric observations and vice versa. We make a case that the global neutral density specification can greatly benefit from this approach based on a number of filtering experiments conducted under the assumption of no model bias. Specific observations considered are (i) neutral mass densities obtained from the accelerometer experiment on board the CHAMP satellite and (ii) electron density profiles obtained from the COSMIC/FORMOSAT-3 mission. Assimilation of the neutral mass density obtained from the CHAMP mission into the TIEGCM is shown to improve the neutral density specification in the vicinity of satellite orbits, but is short of making a global impact unless accompanied by the estimation of the primary driver of the density variability such as solar EUV flux. On the other hand, assimilation of the COSMIC/FORMOSAT-3 electron density profiles into the Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIEGCM) is far more effective than the CHAMP neutral density in terms of improving the global neutral mass density specification. This suggests a synthesis of thermospheric and ionospheric observations into the general circulation model, brought about with the help of the latest EnKF techniques, can effectively increase the geophysical information content of observations.

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Data assimilation of ground GPS total electron content into a physics‐based ionospheric model by use of the Kalman filter

Cited by 96 publications

References 27 publications

Climatology of GPS phase scintillation and HF radar backscatter for the high-latitude ionosphere under solar minimum conditions

Climatology of GPS phase scintillation and HF radar backscatter for the high-latitude ionosphere under solar minimum conditions

GPS TEC, scintillation and cycle slips observed at high latitudes during solar minimum

Thermospheric mass density specification using an ensemble Kalman filter

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