Folie 1

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Noctilucent Cloud (NLC)
( J. Fiedler )
Photo taken at Skagen / Denmark on 1 July 1996,
2230 UT.
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Project TitleSimultaneous NLC Observation and
Temperature Determination in the Polar Summer
Mesopause Region by Lidar.

• Jens Fiedler
• and
• Gerd Baumgarten
• Leibniz-Institute of Atmospheric
• Physics,
• Kühlungsborn, Germany

Activity Duration 31 May 17 June 2002 29
July 13 August 2002
Main Instruments RMR Lidar Weber Lidar
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Spitzbergen, 78 N NLC remote measurement (K
lidar) Temperature in-situ measurement
(falling spheres) Water vapor model calculations
Höffner et al., Atmos. Chem. Phys., 3, 2003
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ALOMAR, 69 N remote measurements Na layer
Weber lidar NLC RMR lidar PMSE ALWIN
radar
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Results during project duration ( 31 May 17
June 29 July 13 August 2002 )

• Measurement times
• RMR lidar
• total 151 hours
• NLC 17 hours
• Weber lidar (technical problems)
• total 6 hours
• temperature 0 hours

Scientific results NLC occurrence frequency
11 NLC layer parameters altitude,
brightness, vertical extension
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RMR Lidar Measurements within NLC Periods 1997
2003 1882 hours
Operators K. Bekkelund, G. Baumgarten, G.
Birkeli, G. von Cossart, J. Fiedler, K.H. Fricke,
A. Jensen, M. Langteigen, S. Loßow, R. Lyngra, R.
Eixmann, C. Fricke-Begemann, T. Köpnick, A.
Schöch, U. von Zahn,
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Analysis Method

• time period
• 1 Jun 15 Aug
• resolution
• 14 min (time)
• 150 m (altitude)

• NLC properties
• brightness ßmax
• altitude (centroid) zc
• thickness (FWHM) dz

NLC time total time
occurrence frequency
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Interannual Variations NLC Occurrence

• brightness classes
• ß 4 7 weak
• ß 7 13 medium
• ß gt 13 strong

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Solar Forcing of NLC Occurrence

• ß-threshold 4
• r 0.52, 0.59

• ß-threshold 13
• r 0.81, 0.88

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Interannual Variations NLC Properties
ß-threshold 4, mean values and 95 confidence
intervals
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Diurnal Variations 1997 - 2003 NLC Occurrence

• harmonic fit for 24-h and 12-h
• r 0.96

• harmonic fit for 24-h and 12-h
• r 0.81 (weak NLC)
• r 0.97 (strong NLC)

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Diurnal Variations Composed Time Series
harmonic fits (24-, 12-h)
altitude
hourly mean values
ß-threshold 4
brightness
harmonic fits (24-, 12-h)
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Diurnal Variations Wavelet Analysis of Composed
Time Series
altitude
brightness
power spectrum (relative), whitenoise
significance levels
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Distributions of NLC Parameters 1997 2003

• mean values and 99 confidence
• zc ð normal distribution
• ßmax, dz ð asymmetric distributions

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Outlook
ALOMAR combines different remote sensing
instruments with the capability to perform
simultaneous and common-volume measurements
within the summer mesopause region.
J
The Weber lidar can provide important information
about the environmental conditions of the NLC
region (i.e. temperature, wave activity using Na
as tracer).
Þ

Re-application for the project Simultaneous NLC
Observation and Temperature Determination in the
Polar Summer Mesopause Region by Lidar.