Identification

Title

Large wind shears and stabilities in the mesopause region observed by Na lidar at midlatitude

Abstract

Unexpected large horizontal winds and wind shears in the lower thermosphere have been observed by rocket soundings and lidars for decades. From 4 years of the Colorado State University sodium wind-temperature lidar data set (2002-2005, total of ~1600 nocturnal hours), we observed an altitude distribution of large wind velocity and wind shears between 80 and 105 km, similar to the results of chemical release experiments. Our lidar data show conclusively that when the observed wind shears are plotted as a function of squared Brunt-Vaisala frequency, N2, they are below the value corresponding to the Richardson number of 1/4, which is a necessary condition of the onset of dynamic instability. This suggests that large wind shears can be sustained in the region of high static stability, e.g., in the lower thermosphere, where large wind shears are often observed by the rocket sounding. The full-diurnal-cycle lidar data enables the extraction of tidal wave components with periods of 24 h, 12 h, 8 h and 6 h, therefore allowing us to reveal the strong correlation of 60%, between large wind shears (>50 m/s/km) and tidal waves. The lidar measured seasonal variation of N2 and tidal amplitudes in the mesosphere and lower thermosphere (MLT) are found to be consistent with the difference in altitude distribution of strong wind shears between winter and summer.

Resource type

document

Resource locator

Unique resource identifier

code

https://n2t.org/ark:/85065/d7j104fx

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

North bounding latitude

South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2010-10-09T00:00:00Z

Frequency of update

Quality and validity

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Conformity

Data format

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version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact