Monthly means of daily temperatures at the 500hPa level (mid-troposphere), 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.
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.
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 4 - Monthly mean lower-stratospheric 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
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 500hPa Temperature