Measurements of Cloud Base Height (CBH) at the Thule High Arctic Atmospheric Observatory (THAAO) are carried out by means of a LUFFT Nimbus CHM15k ceilometer. The ceilometer is a laser remote sensing device with embedded algorithm for determining layers of particles and droplets in the atmosphere. The CHM15k Algorithm provides the Cloud Base Height (CBH) together with the Cloud Penetration Depth (CPD), and it is able to discriminate up to 3 different layers of clouds...