Identification

Title

Austral summer foehn winds over the McMurdo dry valleys of Antarctica from Polar WRF

Abstract

Foehn winds are a prominent feature of the McMurdo Dry Valleys (MDVs) climate, and are responsible for periods of strong winds and warming. The foehn mechanism determined from a case study presented in earlier work is shown here to be robust for a set of the MDVs summer foehn events over the 1994–2009 period using output from the Polar Weather Research and Forecasting Model (Polar WRF). Gap flow south of the MDVs is evidenced by the positive relationship between the pressure gradient and near-surface wind speed along the gap. Subsequently, mountain waves are generated and result in adiabatic warming and the downward transport of warm air into the MDVs, and differences in mountain wave characteristics depend on the ambient wind direction and the degree of flow nonlinearity. Pressure-driven channelling then brings warm foehn air downvalley. Although a large range of synoptic-scale circulation patterns can drive foehn events, the warmest foehn events are typically associated with blocking highs over the Australian sector of the Southern Ocean, leading to warm air advection over continental Antarctica. The episodic nature of foehn events, and the tenuous connections between such events and interannual modes of climate variability, suggests that intraseasonal variability may be more important for determining their frequency and magnitude. The extraordinarily warm austral summer of 2001/2002 across Antarctica shows that advection of warm maritime air into the continental interior and strong flow aloft result in warm foehn conditions and significant melt for the MDVs.

Resource type

document

Resource locator

Unique resource identifier

code

https://n2t.org/ark:/85065/d7q241t1

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

2014-07-01T00:00:00Z

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