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IJRSP Vol.40 [2011] >
IJRSP Vol.40(1) [February 2011] >
| Title: | Comparison of total electron content predicted using the IRI-2007 model with GPS observations over Lagos, Nigeria |
| Authors: | Adewale, A O
Oyeyemi, E O
Adeniyi, J O
Adeloye, A B
Oladipo, O A |
| Keywords: | Total electron content (TEC)
IRI-TEC variation
GPS-TEC variation |
| Issue Date: | Feb-2011 |
| Publisher: | NISCAIR-CSIR, India |
| PACS No.: | 94.20.dt; 94.20.Cf |
| Abstract: | The comparison of IRI-2007 (NeQuick option) derived total electron content
(TEC) (IRI-TEC) with Global Positioning System observations (GPS-TEC) recorded at
Lagos, Nigeria (6.5°N, 3.4°E; dip latitude 2°S) has been done. The observations were carried out using
a dual frequency Novatel GSV 4004B GPS Ionospheric Scintillation and TEC
monitor. The diurnal and seasonal variations of measured TEC were analyzed for
2009, a year of low solar activity.
The TEC values were grouped into four seasons, namely March Equinox (February,
March and April), June Solstice
(May, June and July), September Equinox (August, September and October), and
December Solstice (November, December and January). The IRI-2007 predicts reasonably well the
observed diurnal and seasonal variation patterns of TEC values during all the
seasons. However, the model gave a relatively poor prediction during 0200 –
0600 hrs LT, with the TEC percentage deviation (∆TEC) having values greater
than 50% during all seasons and ∆TEC never exceeded 50% at any other hour of
the day except at 0800 hrs LT during both December Solstice and September
Equinox. The early morning
deviation between predictions and observed vertical TEC (VTEC) could arise
because maximum electron density of the
F2 layer (NmF2) or the shape of the
electron density profile, or both, is not well predicted by the NeQuick model; and
some improvements need to be implemented to obtain better predictions of TEC
over Lagos. |
| Page(s): | 21-25 |
| CC License: |  CC Attribution-Noncommercial-No Derivative Works 2.5 India |
| ISSN: | 0975-105X (Online); 0367-8393 (Print) |
| Source: | IJRSP Vol.40(1) [February 2011]
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