[Location: Location_Category='VERTICAL LOCATION', Location_Type='TROPOSPHERE']
Monthly mean mid-tropospheric temperatures above Australian Antarctic stations.Entry ID: SOE_mid_tropo
Abstract: 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.
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
Data Set Citation
Dataset Originator/Creator: Barnes-Keoghan, I.
Dataset Title: Monthly mean mid-tropospheric temperatures above Australian Antarctic stations.
Dataset Series Name: CAASM Metadata
Dataset Release Date: 2001-04-23
Dataset Publisher: Australian Antarctic Data Centre
Version: 1Online Resource: https://data.aad.gov.au/metadata/records/SOE_mid_tropo
Start Date: 1948-04-01
Temporal Resolution: 30 Day(s)
Quality 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.
Access Constraints Data arising from this project are available from the state of the environment indicator at the provided URL.
Use Constraints This data set conforms to the CCBY Attribution License (http://creativecommons.org/licenses/by/4.0/).
Please follow instructions listed in the citation reference provided at http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=SOE_mid_... when using these data.
Data Set Progress
Distribution Media: HTTP
Role: DIF AUTHOR
Phone: +61 3 6221 2043
Fax: +61 3 6221 2045
Email: I.Barnes-Keogahn at bom.gov.au
Climate and Consultancy Section GPO Box 727 Bureau of Meteorology Tasmania and Antarctica Regional Office
Province or State: Tasmania
Postal Code: 7001
French, J., Burns, G., Greet, P. and French, K. (2000), Antarctic Noctilucent Clouds: The Upper Atmosphere Exposed to View., The Physicist, 37, 3, 85-90
Extended Metadata Properties
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Creation and Review Dates
DIF Creation Date: 2001-04-24
Last DIF Revision Date: 2019-04-11