Indicator 15 - Stratopause region parameters for DavisIndex - Description | Data | Custodian evaluation | Related resources | Parameters |
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| Indicator Definition | Lidar observations at Davis Station, Antarctica, are used to obtain monthly average values of the temperature at the stratopause, the altitude of the stratopause, and the temperature and altitude of the 0.5hPa pressure level. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Responsible Organisation |
 Australian Antarctic Division (details) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Custodians |
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| Theme Area | Atmosphere | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Indicator Type | Condition | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Criteria the Indicator Satisfies |
The following 9 out of 15 criteria
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| Date Input | Monthly measurements | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Monitoring Location |
Davis (details)
Geographic Coverage is
Longitude (78.0 to 78.0)
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| Rationale For Indicator Selection | A general cooling of the stratosphere is predicted to accompany anthropogenically enhanced greenhouse-gas warming of the lower atmosphere. This should lead to changes in the altitude and temperature of the stratopause region, and a decrease in the height of standard pressure surfaces in the stratosphere and mesosphere. However, perturbations to the thermodynamics of the stratopause region may be caused by inter-annual variability in the lower atmosphere, volcanic events, and solar-cycle changes. Long-term quantification of stratopause region parameters will aid in understanding and predicting natural and anthropogenic variability. The 0.5hPa pressure altitude has been chosen as this lies near the stratopause at Davis, and temperatures for this pressure level are routinely obtained by satellite remote sensing instruments. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Design and Strategy For Indicator Monitoring Program | Spatial scale: Davis Station, Antarctica Temporal scale: Monthly Measurement technique: Lidar (532nm wavelength) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Research Issues | Changes in the thermodynamics of the stratoapuse region has implications for the atmosphere at lower altitudes. To obtain a more comprehensive picture of the spatial extent of these changes, the underlying physics, and future implications, the Davis observations should be assimilated into research incorporating a diverse body of observations and model predictions. Important additional data will come the remote sensing of temperatures and winds in the mesopause region, from instruments at Davis including the MF radar and the proposed VHF radar, and other Antarctic measurements. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Data |
Timespan: February-2001 to August-2002. Number of data points: 76. 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. Davis: Stratopause height  Davis: Stratopause temperature  Davis: 0.5 hPa height  Davis: 0.5 hPa Temperature  Davis: Time spent on observations  | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Data Quality, Interpretation and Analysis of Indicator Data |
The raw data used in the analysis of this indicator are obtained from observations by the Davis Lidar in Rayleigh and Doppler modes. In Rayleigh mode, the raw data consist of profiles of the intensity of 532nm laser backscatter versus altitude. The backscatter profiles are converted to profiles of absolute total molecular density using in-situ or extrapolated density measurements for the altitude range 27-28km obtained from contemporary balloon-borne radiosonde measurements. In producing the density profiles, account is made for molecular extinction, including ozone, and background signals due to sky light and instrument noise. The hydrostatically-constrained perfect gas law is used to retrieve the temperature profile from the density profile by integrating down in altitude from a reference altitude. Initiation of the temperature retrieval process uses the estimated temperature from the MSISE-90 climatological model at the altitude where the one-sigma relative uncertainty in absolute density is 20% (typically 60km). Convergence of the temperature retrieval typically is typically achieved 8km below the reference altitude. In Doppler mode, spectral scans of 532nm laser backscatter versus altitude are obtained with a high-resolution Fabry-Perot spectrometer. These measurements are used to infer the temperature profile from analysis of the Doppler broadening of the laser spectrum. In general, Doppler measurements are restricted to altitudes below about 70km based on signal detection considerations. Temperatures are averaged in a 4km altitude range centred on the altitude of the temperature inversion at the stratopause. A 95% confidence interval is provided for each temperature average and estimate of the stratopause altitude. The average altitude (and associated 95% confidence interval) of the 0.5hPa level is obtained from air pressure profiles calculated from lidar-derived density and temperature profiles. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Data Distribution |
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| Data Access Constraints | These data are publicly available for download from the URL given below. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Custodian Evaluation |
For definitions of the Scale categories, consult the Explanation of the Status Categories | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Related resources |
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| Parameters |
The properties link can be used to view details of the parameters measured for this indicator.
Parameters - | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Related URL's |
http://data.aad.gov.au/aadc/portal/download_file.cfm?file_id=2271 Download point for the data - pdf copy of chapter 26 of ANARE Report 146 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
