DWM07 global empirical model of upper thermospheric storm‐induced disturbance winds

Emmert, J. T.; Drob, Douglas P.; Shepherd, G. G.; Hernández, G.; Jarvis, M. J.; Meriwether, J. W.; Niciejewski, R. J.; Sipler, D. P.; Tepley, C. A.

doi:10.1029/2008ja013541

Cited by 122 publications

(149 citation statements)

References 53 publications

Supporting

Mentioning

142

Contrasting

Unclassified

Order By: Relevance

“…The equations for the direct, Pedersen, and Hall conductivities are given in Kelley [1989, appendix B]. The neutral wind field u is supplied by the horizontal wind model (HWM07) Emmert et al, 2008]. HWM07 does not provide vertical wind velocities, and so they are ignored for this study.…”

Section: Modeling the Equatorial Electrojet Currentmentioning

confidence: 99%

Longitudinal and seasonal structure of the ionospheric equatorial electric field

Alken¹,

Chulliat

Maus³

2013

JGR Space Physics

View full text Add to dashboard Cite

[1] The daytime eastward equatorial electric field (EEF) in the ionospheric E-region plays an important role in equatorial ionospheric dynamics. It is responsible for driving the equatorial electrojet (EEJ) current system, equatorial vertical ion drifts, and the equatorial ionization anomaly. Due to its importance, there is much interest in accurately measuring and modeling the EEF. In this work we propose a method of estimating the EEF using CHAMP satellite-derived latitudinal current profiles of the daytime EEJ along with Δ H measurements from ground magnetometer stations. Magnetometer station pairs in both Africa and South America were used for this study to produce time series of electrojet current profiles. These current profiles were then inverted for estimates of the EEF by solving the governing electrostatic equations. We compare our results with the Ion Velocity Meter (IVM) instrument on board the Communication/Navigation Outage Forecasting System satellite. We find high correlations of about 80% with the IVM data; however, we also find a constant offset of about 0.3 mV/m between the two data sets in Africa. Further investigation is needed to determine its cause. We compare the EEF structure in Africa and South America and find differences which can be attributed to the effect of atmospheric nonmigrating tides. This technique can be extended to any pair of ground magnetometer stations which can capture the day-to-day strength of the EEJ.Citation: Alken, P., A. Chulliat, and S. Maus (2013), Longitudinal and seasonal structure of the ionospheric equatorial electric field,

show abstract

Section: Modeling the Equatorial Electrojet Currentmentioning

confidence: 99%

Longitudinal and seasonal structure of the ionospheric equatorial electric field

Alken¹,

Chulliat

Maus³

2013

JGR Space Physics

View full text Add to dashboard Cite

show abstract

“…Further development of the HWM model series is now also continued at the Naval Research Lab. The latest edition is HWM07 [Drob et al, 2008], which has a companion model for high geomagnetic activity, the Disturbance Wind Model DWM07 [Emmert et al, 2008b].…”

Section: Msis and Hwm Modelsmentioning

confidence: 99%

Thermospheric Density and Wind Determination from Satellite Dynamics

Doornbos¹

2012

Springer Theses

156

212

View full text Add to dashboard Cite

“…Richmond et al [2003] used QD coordinates to study the response of high-latitude neutral and ion convection patterns to changes in the interplanetary magnetic field. In the most recent version of the empirical Horizontal Wind Model, HWM07 Emmert et al, 2008], QD coordinates are used to model geomagnetic storm effects on thermospheric winds. One shortcoming of HWM07 is that quiet time highlatitude thermospheric winds, which are similar to ion convection patterns, are not well represented by the geodetic VSH expansion used in the model.…”

Section: Scientific Applicationmentioning

confidence: 99%

A computationally compact representation of Magnetic‐Apex and Quasi‐Dipole coordinates with smooth base vectors

2010

Self Cite

View full text Add to dashboard Cite

[1] Many structural and dynamical features of the ionized and neutral upper atmosphere are strongly organized by the geomagnetic field, and several magnetic coordinate systems have been developed to exploit this organization. Quasi-Dipole coordinates are appropriate for calculations involving horizontally stratified phenomena like heightintegrated currents, electron densities, and thermospheric winds; Modified Apex coordinates are appropriate for calculations involving electric fields and magnetic field-aligned currents. The calculation of these coordinates requires computationally expensive tracing of magnetic field lines to their apexes. Interpolation on a precomputed grid provides faster coordinate conversions, but requires the overhead of a sufficiently fine grid, as well as finite differencing to obtain coordinate base vectors. In this paper, we develop a compact and robust representation of the transformation from geodetic to Quasi-Dipole (QD), Apex, and Modified Apex coordinates, by fitting the QD coordinates to spherical harmonics in geodetic longitude and latitude. With this representation, base vectors may be calculated directly from the expansion coefficients. For an expansion truncated at order 6, the fitted coordinates deviate from the actual coordinates by a maximum of 0.4°, and typically by 0.1°. The largest errors occur in the equatorial Atlantic region. Compared to interpolation on a pre-computed grid, the spherical harmonic representation is much more compact and produces smooth base vectors. An algorithm for efficiently and concurrently computing scalar and vector spherical harmonic functions is provided in the appendix. Computer code for producing the expansion coefficients and evaluating the fitted coordinates and base vectors is included in the auxiliary material.

show abstract

DWM07 global empirical model of upper thermospheric storm‐induced disturbance winds

Cited by 122 publications

References 53 publications

Longitudinal and seasonal structure of the ionospheric equatorial electric field

Longitudinal and seasonal structure of the ionospheric equatorial electric field

Thermospheric Density and Wind Determination from Satellite Dynamics

A computationally compact representation of Magnetic‐Apex and Quasi‐Dipole coordinates with smooth base vectors

Contact Info

Product

Resources

About