State of Environment

Indicator 5 - Monthly mean mid-tropospheric temperatures above Australian Antarctic Stations

Index - Description | Data | Custodian evaluation | Related resources | Parameters

Releasing and tracking of Met. balloon at Law Dome (AAD Photo 1673/ D2) by Rowan Butler, 1985

Indicator Definition

Monthly means of daily temperatures at the 500hPa level (mid-troposphere),
from radiosonde soundings above Australian Antarctic stations Casey, Davis,
Mawson and Macquarie Island.

Responsible
Organisation

Bureau of Meteorology, Department of the Environment and Heritage (details)

Custodians

IAN BARNES-KEOGAHN I.Barnes-Keogahn@bom.gov.au	INVESTIGATOR	Climate and Consultancy Section GPO Box 727 Bureau of Meteorology Tasmania and Antarctica Regional Office Hobart Tasmania 7001 Australia Ph +61 3 6221 2043
CLIMATE SERVICES climate.tas@bom.gov.au	TECHNICAL CONTACT	Climate and Consultancy Section GPO Box 727 Bureau of Meteorology Tasmania and Antarctica Regional Office Hobart Tasmania 7001 Australia Ph +61 3 6221 2043
REGIONAL OBSERVATIONS SECTION climate.tas@bom.gov.au	TECHNICAL CONTACT	Regional Observations Section GPO Box 727 Bureau of Meteorology Tasmania and Antarctica Regional Office Hobart Tasmania 7001 Australia Ph +61 3 6221 2071

Theme Area

Atmosphere

Indicator Type

Condition

Criteria the
Indicator Satisfies

The following 11 out of 15 criteria

1.	Serve as a robust indicator of environmental change
2.	Reflect a fundamental or highly-valued aspect of the environment or an important environmental issue
3.	Be either national in scope or applicable to regional environmental issues of national significance
4.	Provide an early warning of potential problems
5.	Be capable of being monitored to provide statistically verifiable and reproducible data that shows trends over time and, preferably, apply to a broad range of environmental regions
6.	Be scientifically credible
7.	Be easy to understand
9.	Be cost-effective
11.	Contribute to monitoring of progress towards implementing commitments in nationally important environmental policies
13.	Contribute to the fulfillment of reporting obligations under international agreements
15.	Where possible and appropriate, be consistent and comparable with other countries’ and state and territory indicators

For details of indicators, see the State of Environment Bibliography entries 16336 and 16337

Date Input

Monthly measurements

Monitoring Location

Mawson (details) Davis (details) Casey (details) Macquarie Island (details)

Geographic Coverage is

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 660 16' 54.5" S,
long 1100 31' 39.4" E), Davis (lat 680 34' 35.8" S, long 770 58' 02.6" E),
Mawson (lat 670 36' 09.7" S, long 620 52' 25.7" E) and Macquarie Island
(lat 540 37' 59.9" S, long 1580 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.

Data

Timespan: February-1959 to October-2009.
Number of data points: 2682.

To view or download any of the data, you must be logged into the Data Centre Portal. If you return to this indicator, you will find a Search Data link that will allow you to view or extract the data for this indicator.

Casey: Air Temperature

Casey: Air Temperature Anomaly

Davis: Air Temperature

Davis: Air Temperature Anomaly

Macquarie Island: Air Temperature

Macquarie Island: Air Temperature Anomaly

Mawson: Air Temperature

Mawson: Air Temperature Anomaly

Data Quality, Interpretation and
Analysis of Indicator Data

Monthly means are calculated from daily observations of temperature at the 500hPa level. Observations are restricted to within a few hours of 0000UTC to avoid biases and to allow comparison with limited historical data. If less than 25 daily observations are available for a given month, the monthly data are flagged and removed from the State of Environment dataset.

The monthly mid-tropospheric air temperature anomaly is calculated as the difference between the mean mid-tropospheric air temperature for a given month and the long-term mean mid-tropospheric air temperature for that calendar month between 1971 and 2000, so that:

Anomaly (for given month) = Value (for given month) - Long-term Mean (for relevant calendar month)

Although the Bureau of Meteorology uses the period from 1961 to 1990 as the standard period for calculation of long-term means, it was decided that for Antarctic stations, the 1971-2000 dataset was in most cases more complete, and would therefore provide a more accurate long-term mean.

These records require analysis for variability and trends. However, there are likely to be significant errors in the data, and these need to be addressed first (see Research Issues).

The data are subject to a number of quality checks, although these will not prevent errors:

- The radiosonde checks the reasonableness of raw values from the probes whilst converting to temperature.

- The receiving station applies reasonableness checks, generally with the involvement of a human observer.

Data Usage Constraints

The copyright for any data are held by the Commonwealth of Australia.
The user shall give acknowledgement of the source in reference to the data.
Apart from dealings under the copyright Act, 1968, the user shall not reproduce, modify or supply (by sale or otherwise) these data without written permission.

While every effort is made to supply the best data available this may not be possible in all cases. No warranty is given, nor any liability accepted in relation to the information given, except that liability (if any), that is required by law.

Data Distribution

DATA OFFICER AADC metadata@aad.gov.au	Australian Antarctic Division 203 Channel Highway Kingston Tasmania 7050 Australia Ph +61 3 6232 3244
CLIMATE SERVICES climate.tas@bom.gov.au	Climate and Consultancy Section GPO Box 727 Bureau of Meteorology Tasmania and Antarctica Regional Office Hobart Tasmania 7001 Australia Ph +61 3 6221 2043

Data Access Constraints

Data arising from this project are available from the state of the environment indicator URL given below.

Custodian Evaluation

Date entered

Evaluation

9-May-2002

The annual cycle evident in the plots of monthly mean mid-tropospheric temperature makes it hard to see long-term trends but can be removed by using monthly anomalies, which show the difference between the value for a given month and the long-term mean value for that month.

The anomaly data indicate significant warming at Macquarie Island and, to a lesser extent, at Mawson and Casey.

It should be noted that the data have not been corrected for any changes in instrumentation or observing practices.

7-Nov-2002

Condition scale - 5

1 - the environment degraded to the point where rehabilitation is impossible

0	1	2	3	4	5	6	7

7 - the environment is pristine, in perfect condition, no anthropogenic influences

State of Knowledge scale - 4 - Fair

1 - Poor

0	1	2	3	4	5	6	7

7 - Excellent

5-Aug-2004

Despite a recent decrease at Casey, the anomaly data now indicate significant long-term warming at all sites. The warming is more pronounced at Macquarie Island and Casey than at Mawson and Davis.

Condition scale - 4 - fair condition

1 - the environment degraded to the point where rehabilitation is impossible

0	1	2	3	4	5	6	7

7 - the environment is pristine, in perfect condition, no anthropogenic influences

State of Knowledge scale - 4 - Fair

1 - Poor

0	1	2	3	4	5	6	7

7 - Excellent

For definitions of the Scale categories, consult the Explanation of the Status Categories

Related resources

Metadata SOE_mid_tropo - Monthly mean mid-tropospheric temperatures above Australian Antarctic stations.

Project 805 - Meteorology Observations

Scientific Bibliography 17309 - French, J., Burns, G., Greet, P. & French, K. (2000) Antarctic Noctilucent Clouds: The Upper atmosphere Exposed to View. The Physicist, volume 37, Number 3

SOE Indicator 1 - Monthly mean air temperatures at Australian Antarctic Stations

SOE Indicator 2 - Highest monthly air temperatures at Australian Antarctic Stations

SOE Indicator 3 - Lowest monthly air temperatures at Australian Antarctic Stations

SOE Indicator 4 - Monthly mean lower stratospheric temperatures above Australian Antarctic Stations

SOE Indicator 8 - Monthly mean atmospheric pressure at Australian Antarctic Stations

SOE Indicator 12 - Noctilucent cloud observations at Davis

SOE Indicator 13 - Polar stratospheric cloud observations at Davis

SOE Indicator 14 - Midwinter atmospheric temperature at altitude 87km

Parameters

The properties link can be used to view details of the parameters measured for this indicator.

Parameter Name	Unit of measure	Properties
Air Temperature	deg C	(properties)
Air Temperature Anomaly	deg C	(properties)

The following parameters and/or sensor notes are from the metadata record.

Parameters -
EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC TEMPERATURE > AIR TEMPERATURE

Related URL's

http://data.aad.gov.au/aadc/portal/download_file.cfm?file_id=1161
Download page for Australian Antarctic Data Centre

Username:
Password:

SIMR - (State of Environment)

State of Environment

Indicator 5 - Monthly mean mid-tropospheric temperatures above Australian Antarctic Stations