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Observations of Dramatic Enhancements to the Mesospheric K Layer
Author(s) -
Jiao J.,
Yang G.,
Wang J.,
Feng W.,
Plane J. M. C.
Publication year - 2017
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 - 10.1002/2017gl075857
Subject(s) - ionosonde , ion , dissociative recombination , sporadic e propagation , mesosphere , atomic physics , physics , meteor (satellite) , cluster (spacecraft) , ionosphere , electron , electron density , materials science , atmospheric sciences , chemistry , geophysics , meteorology , recombination , stratosphere , biochemistry , quantum mechanics , computer science , gene , programming language
Highly concentrated layers of atomic K have been observed in the mesosphere above Yanqing near Beijing (40°N, 116°E). The K density in these narrow layers exceeds 1,100 cm −3 (at least 4 times higher than reported elsewhere), and the K/Na ratio is superchondritic by a factor of 3–4. A model with detailed metal ion chemistry, supported by ancillary measurements from a nearby ionosonde and meteor radar, is used to show that these sporadic K layers can be produced from a strong sporadic E layer (critical frequency > 11 MHz) that descends from above 100 km at a velocity of 1–2 km h −1 . This allows most of the Na + ions to be neutralized before the remaining ions are dumped around 90 km, where the higher pressures and colder temperatures facilitate the formation of K + .N 2 and K + .CO 2 cluster ions. These cluster ions then undergo dissociative recombination with electrons to form K.