If the CALIOP data was obtained from the NASA Atmospheric Science Data Center (ASDC), then here is the webpage describing how to format the acknowledgement and create a citation:
Here is an example of a data availability/acknowledgement statement, reworded to explicitly state the CALIOP data.
“The CALIOP V4.10 data were obtained from the NASA Langley Research Center Atmospheric Science Data Center at https://asdc.larc.nasa.gov/project/CALIPSO."
The exact citation you use depends on the product (level 1, level 2, etc…). Each CALIOP product has a unique DOI. In order to determine the DOI, go to the ASDC webpage containing the product you used and copy the DOI. As an example, I highlighted the DOI for the level 1 product in the screen shot below. After copying the DOI, follow the link that says “Click here for instructions on citing ASDC data.” Use the DOI Citation Formatter linked on that page to format the DOI as needed. For example, here is the formatted citation for the level 1 dataset:
Winker, D. (2016). CALIPSO LID L1 Standard HDF File - Version 4.10 [Data set]. NASA Langley Atmospheric Science Data Center DAAC. https://doi.org/10.5067/CALIOP/CALIPSO/ ... DARD-V4-10