| Abstrakt: |
Abstract. The latitudinal effect in the variations observed values profile of Bo, hmF2 and NmF2 for the F2 layer of the equatorial region during the quiet period at low solar activity was studied. Digisonde data for year 2010, a year of low solar activity from three equatorial stations in the African and Southern American sectors namely; Ilorin, Nigeria (8.5 ° N, 4.5 ° E, −2.96 dip) Fortaleza, Brazil (3 ° S, 38 ° W, −7.03 dip) and Jicamarca, Peru (12 ° S, 76.8 ° W, 0.74 dip) were used for the study. During the March equinox; it was observed that the Bo peaks at 1200 hour LT time and the bite-out and the pre-noon peak of NmF2 were also observed at this same time at Ilorin station. A similar feature was also observed at Fortaleza and at Jicamarca the NmF2 peaks at 1000 hour LT and Bo peaks at 1500 hour LT. September equinox shows a general deviation from what was observed during the March equinox, at Ilorin and at Fortaleza Bo peaks at 1100 hour LT and at Jicamarca it was observed at 1500 hour LT. During the June solstice at Ilorin, Bo peaks at 1500 hour LT with the bite-out of the NmF2, and at Fortaleza it was observed at 1200 hour LT with the peak of NmF2 at 1500 hour LT. There was a shift at Jicamarca, in which two peaks were observed at 1100 and 1500 hour LT respectively. December solstice shows distinct double peaks of Bo at Ilorin and Fortaleza and a different feature was observed at Jicamarca. It was observed that the results from Ilorin and Fortaleza are similar and that of Jicamarca are different from those of other two stations. The peculiarity at Jicamarca is attributed to its closeness to the crest of the equatorial anomaly than these other two stations in the geomagnetic latitude as compared the geographic latitude. This is the second time in our studies that two stations from different latitude will be presented is being having similar profile. These variations observed may be due to effect of the latitudinal differences and the features observed find their explanation in the dynamics of the equatorial ionosphere of the stratospheric-ionospheric couplings. [ABSTRACT FROM AUTHOR] |
