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Oscillations in polar mesospheric summer echoes and bifurcation of noctilucent cloud formation
Author(s) -
Sugiyama Takuya,
Muraoka Yoshikazu,
Sogawa Hisato,
Fukao Shoichiro
Publication year - 1996
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/96gl00383
Subject(s) - polar , atmospheric sciences , radar , geology , geophysics , meteorology , physics , astronomy , computer science , telecommunications
Oscillations having periods of 5.5 days are found in polar mesospheric summer echoes (PMSEs) observed during 1980 to 1984 with the MST radar at Poker Flat, Alaska. Simulations of noctilucent cloud (NLC) formation are made in the case that embryos for cloud ice particles are proton‐hydrates H + (H 2 O) n (PHs). Results show that cloud formation bifurcates from a stably steady structure into a quasi‐steady and a stably oscillatory structure in accordance with an increase of humidity. By capturing electrons, descending crowds of ice particles may cause PMSEs. The cyclic behavior of PMSEs is considered to be an indication of the in situ origin of NLCs.