Identification

Title

The semiannual oscillation of the tropical zonal wind in the middle atmosphere derived from satellite geopotential height retrievals

Abstract

The dominantmode of seasonal variability in the global tropical upper-stratosphere and mesosphere zonalwind is the semiannual oscillation (SAO). However, it is notoriously difficult to measure winds at these heights from satellite or ground-based remote sensing. Here, the balance wind relationship is used to derive monthly and zonally averaged zonal winds in the tropics from satellite retrievals of geopotential height. Data from the Aura Microwave Limb Sounder (MLS) cover about 12.5 yr, and those from the Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics (TIMED) Sounding of the Atmosphere Using Broadband Emission Radiometry (SABER) cover almost 15 yr. The derived winds agree with direct wind observations below 10 hPa and above 80 km; there are no directwind observations for validation in the intervening layers of the middle atmosphere. The derived winds show the following prominent peaks associated with the SAO: easterlymaxima near the solstices at 1.0 hPa, westerlymaxima near the equinoxes at 0.1 hPa, and easterlymaxima near the equinoxes at 0.01 hPa. The magnitudes of these three wind maxima are stronger during the first cycle (January at 1.0 hPa andMarch at 0.1 and 0.01 hPa). The month and pressure level of the wind maxima shift depending on the phase of the quasi-biennial oscillation (QBO) at 10 hPa. During easterly QBO, the westerly maxima are shifted upward, are about 10m s(-1) stronger, and occur approximately 1 month later than those during the westerly QBO phase.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d74t6mw1

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

2017-08-01T00:00:00Z

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