State of Environment

Indicator 8 - Monthly mean atmospheric pressure at Australian Antarctic Stations

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

Southern Ocean at sunrise (AAD Photo 1375B3) by unknown

Indicator Definition

Monthly means of three-hourly pressures, reduced to mean sea level, for
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
8.	Be monitored with relative ease
9.	Be cost-effective
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) Atlas Cove (details) Davis (details) Casey (details) Macquarie Island (details) Spit Bay (details)

Geographic Coverage is

Rationale For Indicator Selection

Measurement of the pressure over Antarctica and the Southern Ocean is
considered important for monitoring behaviour of pressure systems on a local
and global scale, which will help to interpret global climate change.

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).

Frequency: Monthly.

Measurement technique: Barometry.

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 site location or exposure, and 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.

Data

Timespan: April-1948 to October-2009.
Number of data points: 4973.

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.

Atlas Cove, Heard Island: Air pressure

Casey: Air pressure

Casey: Air Pressure Anomaly

Davis: Air pressure

Davis: Air Pressure Anomaly

Macquarie Island: Air pressure

Macquarie Island: Air Pressure Anomaly

Mawson: Air pressure

Mawson: Air Pressure Anomaly

Data Quality, Interpretation and
Analysis of Indicator Data

Mean monthly atmospheric pressure is calculated from all the available 3-hourly observations made during a given month. Each three-hourly air pressure observation is 'reduced' to the equivalent value at mean sea level, using an algorithm embedded in the AWS. If less than 200 observations are present for that month, the monthly value is flagged and removed from the State of Environment dataset.

The monthly atmospheric pressure anomaly is calculated as the difference between the mean atmospheric pressure for a given month and the long-term mean atmospheric pressure 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).

With regard to Heard Island, unfortunately, the two AWS are not &normal& ones (they are actually ocean drifting buoys that have been strapped down). They do provide temperature and pressure, but not wind or daily maximum and minimum temps. Also, they do not report to a fixed, regular schedule, instead sending when they are within the satellite footprint. The system set up for the other sites assumes the regular 3-hourly schedule. The irregularity of the Heard data could cause curious biases, which have not been explored. Also, the criteria used to flag that there are &enough& data (>200 obs in the month) may not really work with these more frequent, and irregular, reporting schedules.

Heard Island (Atlas Cove)
WMO number: 95997
Elevation: 3 m
Barometer elevation: 3.5 m

Heard Island (The Spit)
WMO number: 94997
Elevation: 12 m
Barometer elevation: 12.5 m

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

8-May-2002

The data show that there has been a significant decrease in monthly mean atmospheric pressure at the Antarctic sites, but not at Macquarie Island. The anomaly data, which show the difference between the value for a given month and the long-term mean value for that month, support this observation.

It should be noted that the data have not been corrected for any changes in site location, site exposure, 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

The significant decrease in monthly mean atmospheric pressure at the Antarctic sites has continued. Pressure has also declined at Macquarie Island of late, but the long-term decrease there is not significant.

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 - 5

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_air_pressure - Monthly mean atmospheric pressure for Australian Antarctic Stations

Project 805 - Meteorology Observations

Scientific Bibliography 17261 - CSIRO Impacts and Adaptation Working Group (IAWG) (2001) Climate Change Impacts for Australia. CSIRO Sustainable Ecosystems, Aitkenvale, Queensland, pp 8

Scientific Bibliography 17262 - White, W.B. & Peterson, R.G. (1996) An Antarctic Circumpolar Wave in Surface Pressure, Wind, Temperature and Sea-Ice Extent. Nature, Volume 380, pp 699-702.

Scientific Bibliography 17264 - CSIRO (2001) Climate Change Projections for Australia. Climate Impact Group, CSIRO Atmospheric Research, Melbourne pp.8

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

SOE Indicator 7 - Monthly mean of three-hourly wind speeds (m/s)

SOE Indicator 38 - Mean sea level for the Antarctic region

SOE Indicator 62 - Water levels of Deep Lake, Vestfold Hills

Parameters

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

Parameter Name	Unit of measure	Properties
Air Pressure Anomaly	hPa	(properties)
Air pressure	hPa	(properties)

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

Parameters -
EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC PRESSURE > SEA LEVEL PRESSURE
EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC PRESSURE > SURFACE PRESSURE

Sensors -
AWS

Related URL's

http://data.aad.gov.au/aadc/portal/download_file.cfm?file_id=969
Download page for Australian Antarctic Data Centre

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SIMR - (State of Environment)

State of Environment

Indicator 8 - Monthly mean atmospheric pressure at Australian Antarctic Stations