Open AccessStratification of the F 2 layer observed in Southeast Asia
Author(s) -
Lynn K. J. W.,
Harris T. J.,
Sjarifudin M.
Publication year - 2000
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2000ja900056
Subject(s) - magnetic dip , ionosonde , geology , latitude , stratification (seeds) , equator , geophysics , sunrise , f region , geodesy , atmospheric sciences , electron density , ionosphere , physics , plasma , seed dormancy , germination , botany , quantum mechanics , dormancy , biology
This paper describes the latitudinal variation in F 2 stratification [ Balan and Bailey , 1995] as observed by a number of oblique and vertical ionosondes operating in Southeast Asia during 1997. Stratification of the F 2 layer was seen at dip latitudes from 4°S to 18°S on the southern side of the magnetic equator but did not occur at the closest reflection point to the magnetic equator (dip latitude = 2.3°N). The observed transient cusp (vertical ionosonde) or additional nose (oblique ionosonde) was defined as an F 3 layer or an F 1.5 layer depending on whether it occurred above or below the layer which maintained continuity with the normal F 2 layer peak. Within the zone of occurrence, the transient layer was commonly seen as an F 3 layer at reflection points closest to the magnetic equator but invariably as an F 1.5 layer at reflection points farther from the magnetic equator. These observations suggest that the distortion in the equatorial electron density profile associated with the phenomenon moved toward the base of the F 2 layer as magnetic field lines descended with increasing latitude. Stratification of the F 2 layer commenced at the same local time (e.g., 0845 LT in November 1997) throughout the longitudinal range of coverage and was associated with a rapid rise in F 2 layer height following sunrise. The stratification ended at times varying from 1300 LT to sunset and was associated with a fall in the height of F 2 peak electron density. The region of maximum F 2 layer stratification lay between the magnetic equator and the peak of the southern equatorial anomaly.