Observations of strong wind shears and temperature enhancements during several sporadic Na layer events above Haleakala

Chester S. Gardner; Xin Tao; George C. Papen

doi:10.1029/95GL02555

Observations of strong wind shears and temperature enhancements during several sporadic Na layer events above Haleakala

Chester S. Gardner, Xin Tao, George C. Papen

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Abstract

We describe two sporadic Na (Na_s) layer events observed on 26 September and 6 October 1993 by the Na Wind/Temperature (W/T) lidar above Haleakala, Maui (20.8°N, 156.2°W) during ALOHA‐93. Both events occurred between 90 and 95 km altitude and appeared to be associated with large amplitude gravity waves. Both were accompanied by temperature enhancements of more than 40 K. The temperature and Na density variations at the peak of the Na_s, as well as the vertical motions of the Na_s layers and regions of elevated temperature were highly correlated. The vertical wind structure exhibited no unusual characteristics in the vicinities of the Na_s. The zonal wind profile for the 6 October event exhibited a very strong vertical shear approximately 1 km below the Na_s layer that approached the dynamic instability limit of 42 m/s/km. However the polarity of the shear was opposite that predicted by the classical wind shear theory of sporadic E layers (E_s) formation.

Original language	English (US)
Pages (from-to)	2809-2812
Number of pages	4
Journal	Geophysical Research Letters
Volume	22
Issue number	20
DOIs	https://doi.org/10.1029/95GL02555
State	Published - Oct 15 1995
Externally published	Yes

ASJC Scopus subject areas

Geophysics
Earth and Planetary Sciences(all)

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10.1029/95GL02555

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title = "Observations of strong wind shears and temperature enhancements during several sporadic Na layer events above Haleakala",

abstract = "We describe two sporadic Na (Nas) layer events observed on 26 September and 6 October 1993 by the Na Wind/Temperature (W/T) lidar above Haleakala, Maui (20.8°N, 156.2°W) during ALOHA‐93. Both events occurred between 90 and 95 km altitude and appeared to be associated with large amplitude gravity waves. Both were accompanied by temperature enhancements of more than 40 K. The temperature and Na density variations at the peak of the Nas, as well as the vertical motions of the Nas layers and regions of elevated temperature were highly correlated. The vertical wind structure exhibited no unusual characteristics in the vicinities of the Nas. The zonal wind profile for the 6 October event exhibited a very strong vertical shear approximately 1 km below the Nas layer that approached the dynamic instability limit of 42 m/s/km. However the polarity of the shear was opposite that predicted by the classical wind shear theory of sporadic E layers (Es) formation.",

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T1 - Observations of strong wind shears and temperature enhancements during several sporadic Na layer events above Haleakala

AU - Gardner, Chester S.

AU - Tao, Xin

AU - Papen, George C.

PY - 1995/10/15

Y1 - 1995/10/15

N2 - We describe two sporadic Na (Nas) layer events observed on 26 September and 6 October 1993 by the Na Wind/Temperature (W/T) lidar above Haleakala, Maui (20.8°N, 156.2°W) during ALOHA‐93. Both events occurred between 90 and 95 km altitude and appeared to be associated with large amplitude gravity waves. Both were accompanied by temperature enhancements of more than 40 K. The temperature and Na density variations at the peak of the Nas, as well as the vertical motions of the Nas layers and regions of elevated temperature were highly correlated. The vertical wind structure exhibited no unusual characteristics in the vicinities of the Nas. The zonal wind profile for the 6 October event exhibited a very strong vertical shear approximately 1 km below the Nas layer that approached the dynamic instability limit of 42 m/s/km. However the polarity of the shear was opposite that predicted by the classical wind shear theory of sporadic E layers (Es) formation.

AB - We describe two sporadic Na (Nas) layer events observed on 26 September and 6 October 1993 by the Na Wind/Temperature (W/T) lidar above Haleakala, Maui (20.8°N, 156.2°W) during ALOHA‐93. Both events occurred between 90 and 95 km altitude and appeared to be associated with large amplitude gravity waves. Both were accompanied by temperature enhancements of more than 40 K. The temperature and Na density variations at the peak of the Nas, as well as the vertical motions of the Nas layers and regions of elevated temperature were highly correlated. The vertical wind structure exhibited no unusual characteristics in the vicinities of the Nas. The zonal wind profile for the 6 October event exhibited a very strong vertical shear approximately 1 km below the Nas layer that approached the dynamic instability limit of 42 m/s/km. However the polarity of the shear was opposite that predicted by the classical wind shear theory of sporadic E layers (Es) formation.

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Observations of strong wind shears and temperature enhancements during several sporadic Na layer events above Haleakala

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