Geoscience Reference
In-Depth Information
Figure 4.
Cloud top height probability density functions (Figure 4a) and cumulative PDF (CPDF)
(Figure 4b) for the highest cloud structure established from: LITE (local method applied on September,
1994), GLAS (operational algorithm, applied on last week of September and first 2 week of October,
2003), and CALIOP (operational algorithm, applied on September, 2006. The CPDF previously
retrieved by Winker et al. (1998) with LITE data and the CDPF for ISCCP on the footprint of the LITE
orbits on September, 1994 are also given.
Cloud Top CPDF
Figure 4a and 4b shows respectively the top of cloud PDF, and cumulative PDF
(CPDF) as obtained from the datasets of LITE (local method), GLAS (operational
algorithm) and CALIOP (operational algorithm). These CPDF indicate good agree-
ment for low-level clouds up to an altitude of approximately 3 km. There are very few
differences between GLAS and CALIOP for all CTH, whereas the LITE CPDF shows
a stronger sensitivity to high clouds. Since LITE has a higher value of the SNR, it is
better able to detect high altitude semitransparent cloud structures. Note that for the
low level clouds (CTH <~3 km), the results in Figure 4b are in good agreement with
