Continual initialization of the TING model with GAIM electron densities: ionospheric efffects on the thermosphere

Mon, 01 Jan 2007 00:00:00 GMT

Title: Continual initialization of the TING model with GAIM electron densities: ionospheric efffects on the thermosphere Authors: A. G. Burns; R. W. Schunk; Jee, Geonhwa; L. Scherliess; L. Zhu; J. J. Sojka; D. C. Thompson; S. C. Solomon; W. Wang Abstract: In order to study the effects of ionospheric plasma densities on the thermosphere, electron and O+ densities in the Thermosphere Ionosphere Nested Grid (TING) model are replaced by electron densities from the Global Assimilation of Ionospheric Measurements (GAIM) model at pressure level z=0 (about 230 km altitude) and above during April 1-4, 2004. There was an extended quiet period during this interval followed by a moderate geomagnetic storm. The ingestion of the GAIM electron densities had little effect on the neutral temperature and composition during the quiet period before the storm, but there were noticeable global effects on the neutral winds that most probably resulted from changes in ion drag. During disturbed periods, the changed electron densities produced much more significant effects on the global thermosphere. The increased auroral electron densities enhanced the Joule heating rate, in addition to the ion drag, which resulted in significant global changes not only in the neutral winds, but also in the neutral temperature and composition. The results of our study substantiate that having correct ionospheric plasma densities are critical to accurately predicting the thermosphere in the coupled thermosphere ionosphere model and also indicates that coupled ionosphere and thermosphere need to be improved at the same time in coupled thermosphere ionosphere model.

Climatology of longitudinal structure observed in the TOPEX TEC measurements

Mon, 01 Jan 2007 00:00:00 GMT

Title: Climatology of longitudinal structure observed in the TOPEX TEC measurements Authors: Kim, E.; Kim, Yong Ha; Jee, Geonhwa Abstract: Since the launch on 10 August 1992, the TOPEX/Poseidon mission provided an extensive database of vertical TEC over the ocean until it ended its mission on October 2005. Data from about 14 years of TOPEX TEC observations were analyzed to study the climatology of longitudinal structure at low and middle latitude regions. For the analysis, TEC data were binned by season and solar activity for geomagnetically quiet conditions (Kp < 2) to create TEC maps in magnetic latitude and longitude for several local time sectors. These maps show not only the annual and semiannual anomalies well-known from climatological studies of NmF2, but also the wavenumber-4 structure of the equatorial anomaly. In particular, the latter is the ionospheric feature recently identified from satellite measurements and closely correlated with the longitudinal structure of the vertical E×B drift. Furthermore, this strongly indicates the coupling between the upper atmosphere and the lower atmosphere.

DSpace Collection:

Continual initialization of the TING model with GAIM electron densities: ionospheric efffects on the thermosphere

Climatology of longitudinal structure observed in the TOPEX TEC measurements