Deutsches Zentrum für Luft- und Raumfahrt e.V. Institut für Physik der Atmosphäre http://www.dlr.de/ipa 14.08.2015

Temperature Lidar for Middle Atmosphere Research (TELMA)

Compact Rayleigh Autonomous Lidar (CORAL)

New Lidar Systems at the German Aerospace Center B. Kaifler, N. Kaifler, C. Büdenbender, B. Witschas, P. Gomez, M. Rapp Institute of Atmospheric Physics

Airborne Lidar for Studying the Middle Atmosphere (ALIMA)

10 km

50 km

100 km T, T’, w, w’ <T’w’>, nFe

T, T’, n

T, T’, w, w’ <T’w’>, n

Introduction A new middle atmosphere group was started 2.5 years ago at the DLR Institute of Atmospheric Physics in Oberpfaffenhofen. Our main objective is to study dynamical coupling processes by gravity waves from the troposphere into the stratosphere and mesosphere by characterizing the complete life cycle of gravity waves employing observational and modelling tools. As LIDAR is currently the only available technique which allows continuous atmospheric observations from ground level to 100 km, we focus on development and installation of a new set of LIDAR systems.

Fig. 1: TELMA operating during DEEPWAVE at Lauder, New Zealand, 2014

Motivation: Gravity wave parameters from ground to 100 km, Technology test bed

• Temperature soundings 2-100 km, 10 min resolution • Combined Rayleigh-/Raman-/Brillouin-/Sodium lidar • Novel OPO-based laser system: 9 W at 532 nm,

0.8 W at 589 nm • Mobile system integrated into 8 foot container • Designed for remote operation

Motivation: Daily soundings, statistical analysis of gravity waves

Fig. 6: CORAL container Autonomous operation

• Client-/server software (C++) controls lidar operation & container systems

• Multi-threaded real-time system running on Linux computers

• Message-based data distribution system

• Uniform command language for hardware configuration & system parameter settings

• Self-monitoring and fault protection algorithms

Motivation: Very high-resolution gravity wave measurements

Fig. 8: ALIMA onboard the research aircraft HALO

Fig. 9: Prototype of linear Nd:YAG oscillator operating at 1116 nm wavelength

Fig. 11: Conversion efficiencies (preliminary results)

• Temperature and vertical wind 15-100 km, 30 seconds resolution

• Doppler iron lidar (372 nm) • High-power laser: 9 W at

372 nm, 6 W at 558 nm • 18 inch telescope • Narrow-band daylight filters • Momentum flux

measurements in ground-based configuration (two co-planar beams)

• First airborne measurement in 2018

Fig. 10: Time traces of seeded (blue) and unseeded laser pulses (red)

P. Mahnke, D. Sauder, G. Geyer, J. Speiser Institute of Technical Physics

Fig. 3: Example: 13 hours of temperature measurements

844.748 844.750 844.752 844.754 844.756 844.758 844.7600

1

2

3

4

5

6

7 layer 19 (15 atmospheric range gate) layer 20 (16 atmospheric range gate) layer 21 (17 atmospheric range gate) layer 22 (18 atmospheric range gate) layer 23 (19 atmospheric range gate)

inte

nstiy

/(104 L

SB

)

absolute frequency/(THz)

Remarkable influence due to Mie scattering

from a cirrus cloud

Fig. 5: Measured Rayleigh–Brillouin line shapes for different distances from the A2D lidar. Witschas et al., Opt. Lett. (2014).

Fig. 7: All-sky image and automatic cloud detection

cloud stars

• Temperature soundings 30-85 km, 10 min resolution

• Enhanced version of the TELMA Rayleigh lidar

• Improved container design • Redundant sensors, electric

systems, computers

PMT array (32 pixels)

Fizeau (8 GHz FSR)

Interference filter (1 nm)

CCD camera records beam position

Fig. 4: Sketch of the Rayleigh-Brillouin receiver for TELMA

14 inch telescope

Test signal for alignment of Fizeau

Fig. 2: Container with laser and receiver system (left) and telescope (right)

150 µm pinhole