heinemann lidar weddell sea - polar...
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A study of the atmospheric boundary layer in the Weddell Sea using a wind lidar
Günther Heinemann, Rolf ZentekEnvironmental Meteorology, University of Trier,
Germany
SPP 1158Antarktisforschung
Grants:DFG HE 2740/19 Polarstern AWI_PS96_03
Verification data for atmospheric models‐ radiosondes and observations from Polarstern‐ boundary layer measurements using a wind lidar
AWI (2016)
Heinemann 2016
Polarstern cruise PS96: 6 Dec. 2015 – 14 Feb. 2016
LIDAR
Scanning Doppler wind lidar
“Halo-Photonics Streamline“ scanning wind lidar- wavelength 1.5 μm- pulse rate of 15 kHz- eye-safe (class 1m)- resolution 0.038 m/s- accuracy 0.1 m/s
(depending on SNR)- band width 19.4 m/s- 18m gates (6x3), overl.
High-resolution boundary layer measurements: Profiles, stares and RHI scans (range up to 10km) of wind, turbulence, aerosols
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Scanning patternsDual stare, triple stare
windVR
VR
VRV
V
North or reference direction (ship heading)VR = radial (line of sight LOS) wind)
Scanning patterns: Dual stare
windVR
VR
V
α1
r V r cos β r α1Horizontal windWind speed V, direction
tan r α2 α1α1 r α2
r V r cos β r α2
α2r
V r cos β r α1ship heading
Moving ship dual stare
windV
Equivalent to a two‐lidar system observing the same volumewithin a few minutes
Scanning patterns: RHIDual RHI
windVR
V
r
z VR r,θ VH,R r,z cos θ
θ
VH,R r,z V r,z cos β r,z α1
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Scanning patterns: VAD
windV
z
8 beams with constant zenith angle θ (15°)
Wind data processing
VR = radial (line of sight LOS) wind)
Correction for ship heading and velocity
Ship roll and pitch angles (1Hz)
Ship time server (1Hz)
LIDAR INS/GPS (10Hz (‐400Hz))
Roll, pitch
LIDAR beams VR(1Hz)
Roll/pitch‐corrected LIDAR
beams VR
Wind vector relative to the ship’s heading
radial wind 28 Dec. 1500 UTC
triple staretriple RHI280, 255, 23510 repeats
0‐403 repeats
6s averages
Turbulence Ronne polynya
dual stare 280, 255, 30 repeats
radial wind 13 Jan. 2016, 0800 UTC
2s averages60 seconds 60 seconds
Fast ice edge Lee of the ship
13 Jan. 2016, 0930 UTC
‐17°C5‐6m/s
0, 35 deg
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A23A 17 Jan20160910 UTC
© Umweltmeteorologie Universität Trier
50 km
Iceberg A23A Lidar
Station 1
Station 2
Station 3
Start
Iceberg A23A
10 m/s
LLJLLJ
VAD 17 Jan. 2016
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Station 2 RHI
SummaryBetween 23 December 2015 and 30 January 2016: Vertical wind profiles (VAD) scans every 10‐15min, at lot of RHI scans and stares 2‐3 radiosondes per day
First time of wind lidar measurements on a ship in the Antarctic
Atmospheric model: COSMO‐CLMCCLM‐15km simulations for 2002‐2015 (ERA‐I)
In progress:CCLM‐15km Jan.2016
CCLM‐5km2002‐2016
Planned:CCLM‐1kmDec. 2015 –Jan.2016
Ebner et al. (2014)
Sea ice / oceanmodel FESOM (down to 3km)
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Heinemann 2016
Melt ponds Weddell Sea
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