Stratopause region parameters for DavisEntry ID: SOE_STRATOPAUSE
Abstract: 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.
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
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)
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.
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Start Date: 2001-02-07
Temporal Resolution: monthly
ISO Topic Category
Quality 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.
Access Constraints These data are publicly available for download from the URL given below.
Use Constraints This data set conforms to the PICCCBY Attribution License
Data Set Progress
Role: TECHNICAL CONTACT
Role: DIF AUTHOR
Phone: +61 3 6232 3382
Fax: +61 3 6232 3496
Email: andrew.klekociuk at aad.gov.au
Australian Antarctic Division 203 Channel Highway
Province or State: Tasmania
Postal Code: 7050
Klekociuk, A.R. (2001). Rayleigh LIDAR measurements of mean stratopause region temperatures above Kingston, Tasmania (43.0 degrees S, 147.3 degrees E) betweeen March 1997 and April 1999. ANARE Report 146, Australian solar terrestrial and space physics research Edited by R.J. Morris and P.J. Wilkinson. Available online at the url below.
Creation and Review Dates
DIF Creation Date: 2001-09-04
Last DIF Revision Date: 2008-04-10