Identification

Title

Seasonal variations of the mesospheric Fe layer at Rothera, Antarctica (67.5°S, 68.0°W)

Abstract

Lidar observations of Fe densities between 75 and 105 km above Rothera, Antarctica, are used to characterize the seasonal variations of the mesospheric Fe layer near the Antarctic Circle and the differences are compared to the South Pole. The maximum Fe abundance occurs in late autumn (early May) at Rothera, rather than in midwinter. A secondary Fe enhancement occurs 6 months later in late spring (October–November) prior to the formation of polar mesospheric cloud (PMC) layers in summer. The midsummer Fe layer is 3 km lower at Rothera because Fe depletion by PMC layers near the mesopause is not as extensive or as complete as at the South Pole. These observations are modeled satisfactorily using a mesospheric one-dimensional Fe chemistry model driven by a general circulation model and including a detailed micrometeoroid flux and ablation model. Our study shows that the autumnal maximum in the Fe abundance is caused primarily by the seasonal temperature maximum in the mesopause region, reinforced by the seasonal peak in the meteor input function (MIF). The Fe abundance at Rothera declines throughout the winter in response to the decrease in the MIF and the slowly falling temperatures. The modeled Fe injection rate is ~5 times smaller while the eddy diffusivity values between 80 and 90 km are 4.1 times smaller than the corresponding values used in the South Pole model. This comparison demonstrates the sensitivity of the metal atom densities to the balance between injection by meteoric ablation and removal by downward transport.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d7h70g91

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

2011-01-22T00:00:00Z

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