Identification

Title

Large wind shears and their implications for diffusion in regions with enhanced static stability: The mesopause and the tropopause

Abstract

The NCAR Whole Atmosphere Community Climate Model, with a quasi-uniform horizontal resolution of similar to 25 km and a vertical resolution of 0.1 scale height, produces large vertical shear of horizontal wind with peaks around the mesopause and the tropical and midlatitude tropopause. In these regions, the static stability also reaches peak values and therefore allows large vertical shears before the onset of dynamical instability. The wind shear peaks near the mesopause and the tropopause from the simulation compare well with those identified in observations, including the magnitude, latitudinal dependence, and large shear statistics. By analyzing the probability density functions of the wind shears and their dependence on the zonal scales, it is found that smaller scale processes, likely gravity waves, contribute significantly to the large shears and may play a dominant role in producing the largest shears. Climatological tidal waves have secondary contribution to the large winds and shears, but spectral analysis suggests that they can modulate wind shear perturbations by gravity waves in the mesosphere and lower thermosphere. Implications for tracer transport and mixing in these regions are explored by estimating diffusion coefficients based on the root-mean-square winds, shears, and corresponding spatial scales from model results.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d73f4s85

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

2017-09-19T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

Data format

name of format

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