Evaluation of the TAMDAR Turbulence Algorithm

1
Evaluation of the TAMDARTurbulence Algorithm

• Larry Cornman
• Research Applications Laboratory
• National Center for Atmospheric Research

2
Turbulence Calculations

• The TAMDAR turbulence algorithm is based on
• True airspeed (TAS) values.
• Sampled at 10.67Hz.
• Anti-aliasing filter applied.
• 32-point window 3 second interval.
• Maximum likelihood algorithm.

3
Evaluation Methodology

• Use NCAR algorithm (max. likelihood technique)
  applied to the TAMDAR TAS data
• Use 32-point window.
• Account for anti-aliasing filter.
• Look into other window lengths.

4
Evaluation Methodology, contd.

• Use NCAR algorithm applied to
• UND high-rate TAS (nose and wing ports).
• UND high-rate longitudinal wind.
• UND high-rate vertical wind.
• Simulated data.

5
Data Analysis First Test Flight
True Airspeed from UND and TAMDAR
6
Data Analysis First Test Flight
One-Lag Plot True Airspeed from TAMDAR
7
Data Analysis First Test Flight
Average Spectra True Airspeed from TAMDAR (109
256-pt windows, ½ overlap)
8
Data Analysis First Test Flight
Raw 32-pt Spectra True Airspeed from TAMDAR
9
Data Analysis First Test Flight
EDRs from UND and TAMDAR
10
Data Analysis First Test Flight
Histogram of EDRs from UND and TAMDAR