Institut für Meteorologie und Klimaforschung, Bereich Atmosphärische Umweltforschung (IMK-IFU), Garmisch-Partenkirchen

Lidar Sounding of Free-tropospheric Water Vapour at a High-altitude Station

Thomas Trickl, Hannes Vogelmann

Features:

High-power differential-absorption lidar

Range: 3 - 12 km (SFH outside the PBL)

Vertical resolution: 50-250 m

Accuracy: 5 % under average conditions

Wide spectral tuning range

Good overlap with Zugspitze FTIR (2962 m)

Other instrumentation:

2 high-spectral-resolution FTIRs (Garmisch, Zugspitze), GPS, research aeroplane, in-situ instrumentation

NDSC (NDACC) primary site

2675 m a.s.l.

Vertical range of ground-based DIAL measurements

History of the narrow-band tunable pulsed lasers

Dye lasers:

1975: Wallenstein, Hänsch: E = 0.5 mJ, Δt = 10 ns, Δ = 85 MHz (460 nm)

1976: Blit, Ganiel, Treves: E = 50 mJ, Δt = 0.5 ms, Δ = 30 MHz (585 nm)

1987: Cromwell, Trickl, Kung, Lee: E = 130 mJ, Δt = 10 ns, Δ = 52 MHz (563 nm)

1997: Eikema, Ubachs, Vassen, Hogervorst: E = 220 mJ, Δt = 6.5 ns, Δ = 90 MHz (585 nm)

Solid-state lasers:

1996: Grützmacher, Steiger: 265 mJ at 729 nm

Trickl, Vogelmann: E = 700 mJ, Δ = 100 MHz (800 nm) ???

Durch Minimum an

June 2004: Start of lidar measurements

Noon!

ETH Zürich

Intrusion November 11, 2004ETH Zürich

Zugspitze

Validation, October 2005

Radiosonde:

Meteorological Institute, University of Munich,

launched in the valley

Conclusions:

1. An order-of-magnitude increase in S/N is possible.

2. The planned range up to at least 12 km looks realistic.