Latitudinal extension of equatorial scintillations measured with a network of GPS receivers
Abstract
A latitudinally-spaced network of GPS receivers extending within Colombia, Peru and Chile has served to provide a measurement of the latitudinal extension of scintillations and TEC depletions associated with equatorial plasma bubbles. These observations were obtained with five Leica GPS receivers managed by Boston College and five additional receivers that are operated by other institutions. The BC receivers are controlled by specially-designed software that performs real-time calculations of the scintillation S4 index using the L1 signal. First, we present case-study events in which we correlate the GPS-determined largest magnetic latitude of scintillations, the maximum latitude where TEC depletions are observed and the altitude extension of radar plumes measured concurrently with the JULIA radar. We also show the statistics of scintillations and latitudinal profiles of TEC gathered during the first 6 months of operations of the GPS receiver at Bogota. We observe an almost perfect correlation between scintillations and TEC depletions. We confirm that the maximum latitude of scintillations (and TEC depletions) map quite well to the apex altitude of the radar plumes measured by JULIA. We also compare the location of the northern crest of the equatorial anomaly and the latitude of scintillations, and demonstrate that for 90% of the days between August 2001 and February 2002 scintillations are bounded by the limits of the anomaly crests. The anomaly peaks are the regions where the more intense GPS scintillations and the deepest depletions are seen. We have also correlated the value of the S4 index with the density profiles detected at the magnetic equator by the digisonde operating at Jicamarca. We conclude that the intense S4 values at an anomaly location such as Bogota are attributed to a higher altitude of the equatorial F-region instead of the depth of the local value of the TEC depletion.
- Publication:
-
EGS - AGU - EUG Joint Assembly
- Pub Date:
- April 2003
- Bibcode:
- 2003EAEJA....13464V