The CALIPSO mission team, in collaboration with the Atmospheric Science Data Center (ASDC) at NASA Langley Research Center and AERIS/ICARE Data and Services Center, announces the release of an update to the standard Level 2 lidar data 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 impact 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 dataset did not contain enough information to identify low laser energy shots without having to access the corresponding V4.10 CALIOP Level 1 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 products are identical to those of the V4.10 Level 2 products.
The product is available beginning with data from January 1, 2017 and as of this announcement, through May 31, 2018. Remaining data will be available as it is produced, starting with most recent and working backwards through the mission.