1 Profiling the ABL using a Small Unmanned Meteorological Observer (SUMO) - Wind measurements - Stephanie Mayer PhD – Seminar October 23, 2007

2 Stephanie Mayer, GFI

3 Why remote-controlled aircrafts? repeated, fine-time-scale soundings to investigate meteorological parameters of the ABL economical, controllable and recoverable platform to carry meteorological sensors and instrumentation for in situ measurements of atmospheric parameters (Konrad, 1970) ability to capture a 3-D image of the state of the ABL extremely flexible limitations: fog/clouds, precipitation, storms Stephanie Mayer, GFI

4 Wind triangle Stephanie Mayer, GFI wind vector: wind speed wind direction heading vector: true air speed (TAS) azimuth angle (Ψ) course vector: ground speed (GS) flight-path azimuth (X) heading + wind = course

5 Coordinate systems (1) Stephanie Mayer, GFI

6 Coordinate systems (2) Stephanie Mayer, GFI

7 Coordinate systems (3) Stephanie Mayer, GFI

8 Required variables Stephanie Mayer, GFI nameabbreviationdevice ground speedGS Trimble GPS flight-path azimuthΧ true air speedTASMiniAir angle of sideslipβwind vane azimuth angle (yaw)Ψ inclination angle (pitch)θMicrostrain bank angle (roll)φ

9 Transformation of heading (1) Stephanie Mayer, GFI aerodynamic body geodetic M ba (α,β) M gb (ψ,θ,φ)

10 Transformation of heading (2) Stephanie Mayer, GFI

11 Transformation of heading (3) Stephanie Mayer, GFI Simplified wind equation:

12 Error estimations Stephanie Mayer, GFI applying Gaussian error propagation formular for the wind components: error in wind direction:

13 Assumption: u=v (SW-wind; magnitude: 20m/s) aircraft flies with 30m/s exactly against the wind Example Stephanie Mayer, GFI  GS [m/s] ± 0.1  Χ [°] ± 2  TAS [m/s] ± 0.9  [°] ± 2± 5 GS [m/s]10 TAS [m/s]30  vh [m/s] ± 2± 3 vh [m/s]20  dir ± 6°± 27° taking errors given by the manufacturers

14 Test with a motor-glider Stephanie Mayer, GFI

15 Windprofile Stephanie Mayer, GFI

16 SUMO – wind estimation Stephanie Mayer, GFI

17 SUMO – some technical details Stephanie Mayer, GFI specifications wing span80 cm length75 cm weight600 g performance horizontal (air) speed12-18 m/s 35 m/s climb rate 7-10 m/s 15 m/s altitude range above ground~ 3.5 km horizontal range / endurance~4 km / ~0.5 h

18 Wind estimation by flying in circles Stephanie Mayer, GFI

19 Wind estimation by flying in circles Stephanie Mayer, GFI down GS [m/s]

20 Windprofile – circling method Stephanie Mayer, GFI

21 Near future Stephanie Mayer, GFI comparison of both methods Twinstar II Funjet

22 Summary Stephanie Mayer, GFI two methods of retrieving airborne wind profiles have been shown 1. method: free flight pattern but many components have to be used 2. method: less equipment but limited to circling pattern both methods are quite promising

23 Outlook Stephanie Mayer, GFI comparison of both methods on two small aircrafts (Funjet, Twin Star II) comparison of measurements and model (WRF) data