Forecasting Equatorial Scintillation Activity in Real-time

Details Forecasting Equatorial Scintillation Activity in Real-time Forecasting Equatorial Scintillation Activity in Real-time

Dec 2008

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008agufmsa51a1557r&link_type=abstract

American Geophysical Union, Fall Meeting 2008, abstract #SA51A-1557

Computer Science

Sound

2400 Ionosphere (6929), 2415 Equatorial Ionosphere, 2435 Ionospheric Disturbances, 2439 Ionospheric Irregularities, 2441 Ionospheric Storms (7949)

Scientific paper

It is well-known that the generation of equatorial, F-region plasma density irregularities, via the Generalized Rayleigh-Taylor instability mechanism is critically dependent on the magnitude of the pre-reversal enhancement (PRE) in upward ExB drift velocity after sunset. These plasma density "bubbles" that are generated after sunset lead to the "scintillation" of trans-ionospheric radio wave signals that pass through these bubbles and is commonly referred to as "scintillation activity". Communication and Navigation systems can be severely disrupted by these plasma density irregularities. A measure of scintillation activity is given by the "S4 Index" and a network of Air Force, ground-based UHF and L-band receivers measuring the S4 Index is called the SCIntillation Network Decision Aid (SCINDA) network. This paper describes a technique for automatically forecasting, in real-time, the occurrence or non-occurrence of scintillation activity that relies on real-time data from a ground-based ionospheric sounder at or near the geomagnetic equator. After sunset, the height-rise with time of the bottom-side of the F-layer reflects the magnitude of the upward ExB drift velocity. The value of the ionospheric parameter, h'f (the virtual height of the bottom-side F-layer) at 1930 LT reflects the integrated ExB drift effect on lifting the F-layer to an altitude where the Rayleigh-Taylor instability mechanism becomes important. Incorporating observed h'f values from the Jicamarca, Peru digital sounder at 1930 LT and relating these values to the Total Hourly S4 Index (THS4) observed by the UHF receiver at the Ancon, Peru SCINDA site, it is found that a "threshold" in h'f exists below which, THS4 < 1 (no scintillation activity) and above which THS4 > 1 (scintillation activity). Examples of Jicamarca sounder observations and h'f values prior to the onset of scintillation activity are given. We present results that describe how the threshold value of h'f changes with solar cycle activity and how these results have been incorporated into a real-time capability for automatically forecasting scintillation activity that is available on Google Earth to all interested parties.

Affiliated with

Also associated with

No associations

Rating

Forecasting Equatorial Scintillation Activity in Real-time does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Forecasting Equatorial Scintillation Activity in Real-time, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Forecasting Equatorial Scintillation Activity in Real-time will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1246012