Monthly mean lower stratospheric temperatures above Australian Antarctic stations.

INDICATOR DEFINITION
Monthly means of daily temperatures at the 100hPa level (lower stratosphere), from radiosonde soundings above Australian Antarctic stations Casey, Davis, Mawson and Macquarie Island.

TYPE OF INDICATOR
There are three types of indicators used in this report:
1.Describes the CONDITION of important elements of a system;
2.Show the extent of the major PRESSURES exerted on a system;
3.Determine RESPONSES to either condition or changes in the condition of a system.

This indicator is one of: CONDITION

RATIONALE FOR INDICATOR SELECTION
Global climate models show warming in response to increased greenhouse gas (carbon dioxide, methane etc) concentrations in the atmosphere; this is called the 'enhanced greenhouse effect'. There is interest in climate variability and change not just at the surface, but extending up into the atmosphere. There is evidence of warming in the lower troposphere, but cooling in the lower stratosphere. Ozone depletion processes are also closely linked to stratospheric temperatures.

DESIGN AND STRATEGY FOR INDICATOR MONITORING PROGRAM
Spatial Scale: Australian Antarctic stations: Casey (lat 66 degrees 16' 54.5" S, long 110 degrees 31' 39.4" E), Davis (lat 68 degrees 34' 35.8" S, long 77 degrees 58' 02.6" E), Mawson (lat 67 degrees 36' 09.7" S, long 62 degrees 52' 25.7" E) and Macquarie Island (lat 54 degrees 37' 59.9" S, long 158 degrees 52' 59.9" E).

Temporal scale: Monthly.

Measurement technique: Radiosonde.

RESEARCH ISSUES

There is need to develop a high-quality data set from the available data, correcting erroneous data and estimating missing data. Adjustment may be necessary for changes in instrumentation or observing practices.

Some of these changes are documented in the station history files held by the Regional Observations Section. These history files are currently held as paper records, although more recent information is held electronically and there is an effort to digitise the older records.

Before the data can be used for the detection of change, a concerted effort will need to be made to identify deficiencies in the data, and then make compensations where possible. This is made more difficult by the lack of suitable comparison sites.

Over recent years satellite data exist, which could be used in conjunction with radiosonde data. Satellite data and radiosonde data from other nations should lead to a greater coverage.

LINKS TO OTHER INDICATORS
SOE Indicators 1 - Monthly mean air temperatures for Australian Antarctic Stations
SOE Indicators 2 - Monthly highest air temperatures for Australian Antarctic Stations
SOE Indicators 3 - Monthly lowest air temperatures for Australian Antarctic Stations
SOE Indicators 5 - Monthly mean mid-tropospheric temperature above Australian Antarctic stations
SOE Indicators 6 - Daily mean 10m Firn Temperatures at AWS sites in the AAT (deg C)
SOE Indicators 8 - Monthly mean of three-hourly mean sea level pressures (hPa)
SOE Indicators 11 - Atmospheric concentrations of greenhouse gas species
SOE Indicators 12 - Noctilucent cloud observations at Davis
SOE Indicators 13 - Polar stratospheric cloud observations at Davis
SOE Indicators 14 - Midwinter atmospheric temperature at altitude 87km
SOE Indicators 16 - Extent of summer surface glacial melt (sq km)
SOE Indicators 42 - Antarctic sea ice extent and concentration
SOE Indicators 43 - Fast ice thickness at Davis and Mawson
SOE Indicators 56 - Monthly fuel usage of the generator sets and boilers
SOE Indicators 59 - Monthly electricity usage

Note - Station codes in the data are as follows:
300000 - Davis
300001 - Mawson
300004 - Macquarie Island
300017 - Casey

The fields in this dataset are:
Mean 100hPa Temperature
Year
Month
Station
Station Code
Value
Enough Observations
Number Observations