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Title: Mid‐Latitude Thermosphere‐Ionosphere Na (TINa) Layers Observed With High‐Sensitivity Na Doppler Lidar Over Boulder (40.13°N, 105.24°W)
Abstract

We report the first lidar observations of regular occurrence of mid‐latitude thermosphere‐ionosphere Na (TINa) layers over Boulder (40.13°N, 105.24°W), Colorado. Detection of tenuous Na layers (∼0.1–1 cm−3from 150 to 130 km) was enabled by high‐sensitivity Na Doppler lidar. TINa layers occur regularly in various months and years, descending from ∼125 km after dusk and from ∼150 km before dawn. The downward‐progression phase speeds are ∼3 m/s above 120 km and ∼1 m/s below 115 km, consistent with semidiurnal tidal phase speeds. One or more layers sometimes occur across local midnight. Elevated volume mixing ratios above the turning point (∼105–110 km) of Na density slope suggest in situ production of the dawn/dusk layers via neutralization of converged Na+layers. Vertical drift velocity of TINa+calculated with the Ionospheric Connection Explorer Hough Mode Extension tidal winds shows convergent ion flow phases aligned well with TINa, supporting this formation hypothesis.

 
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Award ID(s):
1744828 2033787 1443726 1452351 2029162
NSF-PAR ID:
10446116
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  ;  ;  ;  ;  
Publisher / Repository:
DOI PREFIX: 10.1029
Date Published:
Journal Name:
Geophysical Research Letters
Volume:
48
Issue:
11
ISSN:
0094-8276
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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