Temporal Development of a Cirrus Cloud

This is an example of lidar measurements of the temporal development of a cirrus cloud. Measurements were made during a joint experiment with the IFU-lidar group on October 27, and 28, 1999, in Garmisch-Partenkirchen. Measurements over one hour between 9:20 and 10:20 GMT are shown. All measurements were made under a zenith angle of 0°. 100 shot were averaged, i.e. ten-second-averages are plotted in each segment (column). During the „white areas“ in Fig. 1, special measurements were made to characterize the signal offset.

In Fig. 1, range corrected signals (@ 1064 nm) are color-coded and plotted against height (above ground) between 0.25 km and 13 km. The color scale gives a good approximation of the aerosol and cloud layering. The different cirrus layer can be seen between approximately 9 and 12 km. Between 0.5 and 2.0 km an elevated aerosol layer is visible.

Figure 1
Fig. 1

In Fig. 2 the same situation as in the previous figure is shown, however, the wavelength is 532 nm. The cirrus structure is not as pronounced as before, because the attenuation of the underlying atmosphere is stronger (extinction increases with decreasing wavelength).

Figure 2
Fig. 2