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

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

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

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

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)

Heinemann 2016

Melt ponds Weddell Sea