Ceilometer Backscatter Profiles

Ceilometer CL51 (Photo: Alfred Wegener Institut)

In October 2010 the Ceilometer CL51 ( VAISALA , Finnland) was mounted  on the monkey deck of Polarstern. It is able to measure cloud heights and vertical backscatter profiles. Short, powerful laser pulses are sent out in a vertical direction every 15 seconds. The reflection of light, backscatter - caused for example by fog, precipitation and clouds - is measured and results in a backscatter profile up to 13.000 m. The raw data of each cruise leg are available at www.pangaea.de.

Before October 2010 the ceilometer LD-WHX 05 (Impulsphysik, Germany) was in use. It offered cloud ceilings up to 3.600m height but no backscatter profiles.

Since ceilometers only offer information from above the instrument the near real time cloud heights are not used automatically for the synoptic observations but used as help for the observers.