October 17, 2018:
CALIPSO Lidar Level 2 STANDARD Version 4.20 Data Release
The CALIPSO mission team, in collaboration with the Atmospheric Science Data Center (ASDC) at NASA
Langley Research Center and HYGEOS/AERIS/ICARE Data Center and Services Center, announces the release of
an update to the standard Level 2 lidar data products.
Version 4.20 Lidar Level 2 Products
The V4.20 CALIOP Level 2 products contain new laser energy science data sets. These
science data sets provide information for filtering out low laser energy shots, a
phenomenon which has impacted CALIOP data quality in the South Atlantic Anomaly region since
mid-2017. A technical advisory of this phenomenon, and the recommended courses of action for mitigating its impace on science analyses,
was posted on the CALIPSO website in June of 2018. In that advisory, it was noted that the existing
V4.10 CALIOP Level 2 data set did not contain enough information to identify low laser energy shots
without having to access the corresponding V4.10 CALIOP Level ` files. In order to provide a simpler
method to exclude affected level 2 data, the new V4.20 CALIOP Level 2 files now includes science data sets for both
532 nm single shot energy (directly from the Level 1 product) and the minimum 532 nm laser energy for each 80 km chunk.
This avoids the necessity to download both the CALIOP Level 1 and Level 2 data products in order to exclude affected
profiles. All other science data sets within the V4.20 Level 2 prdoucts are identival to those
of the V4.10 Level 2 products.
The products are available beginning with data from January 1, 2017 and as of this announcement, through May 31, 2018.
Remaining data will be availabe as it is produced, starting with most recent and working backwards through the
Information about the data products including data availability, user documentation and quality statements, relevant links,
sample read software, and tools for working with the data, etc. can be found at the following ASDC link:
In-depth overviews for the products can be found at the following CALIPSO link to the data quality summaries: