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