temperature within a mid-latitude nlc - a lidar case study · 2017. 9. 25. · coral lidar...

Temperature within a mid-latitude NLC -

A lidar case study

N. Kaifler, B. Kaifler, H. Wilms, M. Rapp G. Stober, C. Jacobi LPMR Workshop, Kühlungsborn 18 – 22 Sep 2017

CORAL lidar

• Compact, autonomous

Rayleigh lidar

• Nd:YAG, 12 W, 532 nm

• 61 cm receiving telescope

History:

1) Sodankylä, Finland

2) Sulzberg, Germany

48.8°N, 13.7°E

May – Sep 2016

634 h

3) Rio Grande,

Argentina

• Rayleigh

temperature and

NLC backscatter in

darkness

• Bright NLC at low altitudes with thin layers

• Modulations in altitude and brightness

Only NLC observation of 2016 season at 48.8°N

CORAL

Only NLC observation of 2016 season at 48.8°N

> Lecture > Author • Document > Date DLR.de • Chart 4

Motivation

NLC as a tracer for

(1) temperature? measure temperature

(2) climate change? where does it come from?

CORAL

NLC and temperature: polar and mid-latitudes

69°N

Lübken et al., JGR, 1996

NLC and temperature: polar and mid-latitudes

Lübken et al., JGR, 1996

69°N

nucleation

growth

sublimation

NLC and temperature: polar and mid-latitudes

69°N 48°N

± 20 K

nucleation

growth

sublimation

18/19 Jul 2016 Lübken et al., JGR, 1996

MSIS

CORAL

SABER

NLC backscatter

NLC and temperature: polar and mid-latitudes

69°N 48°N

± 20 K

nucleation

growth

sublimation

nucleation?

growth?

sublimation?

18/19 Jul 2016 Lübken et al., JGR, 1996

MSIS

CORAL

SABER

NLC backscatter

NLC and temperature: polar and mid-latitudes

69°N 48°N

± 20 K

nucleation

growth

sublimation

nucleation?

growth?

sublimation?

18/19 Jul 2016

(1) Not a local process

Lübken et al., JGR, 1996

MSIS

CORAL

SABER

NLC backscatter

Temperature in vicinity of NLC layer (black contour)

• Density interpolation inside NLC layer

• NLC top boundary follows 155 K isoline

CORAL updated

CARMA

• Drive CARMA

with lidar T

• Vertical wind from

NLC centroid

altitude

• Init at 22 UT

• Constant water

vapour profile

• No diffusion

CARMA

CARMA

• Drive CARMA

with lidar T

• Vertical wind from

NLC centroid

altitude

• Init at 22 UT

• Constant water

vapour profile

• No diffusion

• Evolution of NLC

brightness

CARMA

CORAL

CORAL

CARMA

CARMA

• Drive CARMA

with lidar T

• Vertical wind from

NLC centroid

altitude

• Init at 22 UT

• Constant water

vapour profile

• No diffusion

• Evolution of NLC

brightness

CARMA

CORAL

CORAL

(2) Local conditions determine brightness evolution

Graphic summary

20-2 UT

• Several

observations from

Germany, Latvia,

Estonia and Finland

in this night

(evening, morning)

Visual observations

Heiko Ulbricht, spaceweather.com

19 Sep, 4 UT

20-2 UT

• Meteor radar from Collm

and Kühlungsborn

• Strong 2-day planetary

wave

• Strong southward wind on

18/19 July 2016 at 82 km

• 22 m/s or 80 km/h

Transport of cold air from

polar to mid-latitudes

Mesopause winds

Kühlungsborn, 82 km

20-2 UT

-12 h

- 6 h

80 km/h

NLC transport

20-2 UT

Mesospheric summer echoes

• MSE above

Kühlungsborn likely

precursor for NLC

• Similar layer

morphology

• Higher altitude

consistent with

sedimentation

• Time lag consistent

with transportation

Mesospheric summer echoes

• MSE above

Kühlungsborn likely

precursor for NLC

• Similar layer

morphology

• Higher altitude

consistent with

sedimentation

• Time lag consistent

with transportation

20-2 UT

-12 h

- 6 h

80 km/h

MSE transport

20-2 UT

+12 h

9-19 UT

• Extended field of NLC

52 – 62°N above North

Sea

• Max 18 . 10-10 / sr

CIPS/AIM

16 UT

20-2 UT

• Extended field of NLC

52 – 62°N above North

Sea

• Max 18 . 10-10 / sr

• Aligned wave crests

• 80, 300 and 380 km

CIPS/AIM

16 UT

80 km

1 h

300 km

4 h

380 km

5 h

20-2 UT

-12 h

9-19 UT

16 UT

20 UT, 3 UT

20-2 UT

- 6 h

80 km/h

80 km

1 h

300 km

4 h

Graphic summary

380 km

5 h

Conclusions

• Single NLC observation in 2016 at 48.8°N

• Rayleigh temperature measurements above NLC layer

• Large temperature above NLC, T < 150 K inside and below

• CARMA driven with lidar temperatures give realistic brightness

evolution

• No local nucleation, but determination of brightness variations locally

• NLC widespread in central Europe

• Consistent with visual, wind, MSE and CIPS observations