COSMIC GPS Ionospheric Sensing and Space Weather

By George Hajj, Lou‐Chuang Lee, X. Pi, L. Romans, William S. Schreiner, P. Straus, C. Wang. 2000

171 citations recorded by the source corpus.

As our civilization becomes more dependent on space based technologies, we become more vulnerable to conditions in space weather. Accurate space weather specification and forecasting require proper modeling which account for the coupling between the sun, the magnetosphere, the thermo sphere, the ionosphere and the mesosphere. In spite of the tremendous advances that have been made in understanding the physics behind different space weather phenomena, the ability to specify or predict space weather is limited due to the lack of continuous and extensive observations in these regions. Placing a constellation of GPS receivers in low-Earth orbit, such as the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC), provides an extremely powerful system for continuously and extensively measuring one of these regions, the ionosphere. COSMIC, by use of GPS occultations, will make it possible to obtain continuous and global3-dimensional images of electron density, irregularities and TIDs in the ionosphere and plasmasphere. COSMIC would provide nearly 5600 globally distributed occultations per day suitable for ionospheric sensing. Occultations can be processed individually to obtain vertical profiles of electron density, with vertical resolution of ~lkm, or collectively by means of tomography or data assimilation to obtain 3-D images of electron density or irregularity structure. In this paper we describe the GPS observables for ionospheric sensing and the occultation geometry. Our presentation evolves from discussing simple to more complicated inversion techniques starting with the Abel inversion, gradient-constrained Abel inversion, tomography, and finally data assimilation. In each of these techniques, the accuracy is assessed either via examination of real data from GPSIMET or via simulation. Brief discussions of measuring ionospheric irregularities and TIDs are given.

Subfields: Astronomy and Astrophysics, Molecular Biology, Oceanography

View Paper: https://www.semanticscholar.org/paper/31ff7dfdb50f8fdc87a772b01ec8b3915ece5cbf

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. Sergey Sokolovskiy
2. Christian Rocken
3. Douglas Hunt
4. Richard Anthes
5. William S. Schreiner
6. George Hajj
7. Georg Beyerle
8. Torsten Schmidt

In Molecular Biology

1. C. Hsiao
2. Norbert Jakowski
3. W. Bertiger
4. Isabella Velicogna

In Oceanography

1. Douglas Hunt
2. Sergey Sokolovskiy
3. William S. Schreiner
4. Christian Rocken
5. George Hajj
6. Georg Beyerle
7. E. Kursinski
8. Torsten Schmidt

Citations in the corpus

• The Radio Occultation Experiment aboard CHAMP: Operational Data Analysis and Validation of Vertical Atmospheric Profiles (2004, background): “all-weathercapability, high accuracy and high vertical resolution) offer great potential for atmospheric and ionospheric research, improvement of numerical weather forecasts, space weather monitoring and climate change detection (e.g. Anthes et al., 2000; Hajj et al., 2000; Kuo et al., 2000; Kursins”
• Estimates of the precision of GPS radio occultations from the COSMIC/FORMOSAT‐3 mission (2007, methodology): “The estimates of precision of refractivity between 10 and 20 km and shown in Figure 2 are, fractionally, significantly better than those obtained for temperature by Hajj et al. [2004], apparently, due to smaller separation of the occultation pairs and due to parallel occultation planes.”
• Exploring earth's atmosphere with radio occultation: contributions to weather, climate and space weather (2011, unknown): “The RO method for obtaining atmospheric soundings is described by Kursinski et al. (1997, 2000), Lee et al. (2000), Steiner et al. (2001), Hajj et al. (2002), and Kuo et al. (2004).”
• Motions of the equatorial ionization anomaly crests imaged by FORMOSAT‐3/COSMIC (2007, methodology): “[3] A powerful technique of using signals to derive the vertical profiles is known as the atmospheric/ionospheric radio occultation [Hajj and Romans, 1998; Schreiner et al., 1999; Hajj et al., 2000; Yunck, 2002].”
• A technical description of atmospheric sounding by GPS occultation (2002, methodology): “In addition, tomographic inversions of GPS=MET and Oersted data were performed to obtain 2-dimensional (2-D) and 3-D images of electron density (Leitinger et al., 1997; Rius et al., 1998; Hajj et al., 2000; Escudero et al., 2001).”