Abstract
IT is well established1–3 that the spread-F phenomenon, which is observed as diffuse echoes on the ionograms is a common feature during night time between the dip latitudes 20°N and 20°S. Based on the study of ionograms and published monthly f0F2 bulletins, morphological features of spread F have been reported for several equatorial stations1,4–10. Equatorial spread F as seen on the ionograms generally starts around the time of reversal of the F-region vertical motion in the evening and continues to grow in intensity during the downward motion of the F region11. Usually spread F persists only for few hours and on some occasions continues throughout the night. Sometimes, after the disappearance in the pre-midnight period, spread F reappears in the post-midnight period.
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References
Wright, R. W. H., J. geophys. Res., 64, 2203 (1959).
Lyon, A. J., Skinner, N. J., and Wright, R. W. H., J. atmos. terr. Phys., 19, 145 (1960).
Singleton, D. G., J. geophys. Res., 65, 3615 (1960).
Chandra, H., and Rastogi, R. G., Annls Géophys., 28, 37 (1972).
Booker, H. G., and Wells, H. G., Terr. Mag. Atmos. Electr., 43, 249 (1938).
Bhargava, B. N., J. meteor. geophys., 9, 35 (1958).
Chandra, H., and Rastogi, R. G., Annls Géophys., 28, 709 (1972).
Marasigan, V., J. atmos. terr. Phys., 18, 43 (1960).
Huang, Y. N., and Yeh, C. Y., J. atmos. terr. Phys., 32, 1765 (1970).
Skinner, N. J., and Kelleher, R. F., Annls Géophys., 27, 181 (1971).
Farley, D. T., Balsley, B. B., Woodman, R. F., and McClure, J. P., J. geophys. Res., 75, 7199 (1970).
Mitra, A. P. The Chemistry of the Ionosphere (National Physical Laboratory, New Delhi, 1970).
Martyn, D. F., Proc. IRE, 47, 159 (1959).
Hanson, W. B., McClure, J. P., and Sterling, D. L., J. geophys. Res., 78, 2353 (1973).
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SOMAYAJULU, V., SEN GUPTA, K. & KRISHNA MURTHY, B. Duration of equatorial spread F. Nature 257, 112–113 (1975). https://doi.org/10.1038/257112a0
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DOI: https://doi.org/10.1038/257112a0
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