The datasets are derived from existing ICESat-2 Level 3 standard datasets and designated with the QL suffix. The datasets are sea ice height (ATL07QL), land and vegetation height (ATL08QL), atmospheric layer characteristics (ATL09QL), sea ice freeboard (ATL10QL), and inland surface water (ATL13QL). The new datasets are available through NASA’s National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC, which archives and distributes ICESat-2 data), discoverable through LANCE, and supported by the SNWG Stakeholder Engagement Program (SEP).
The ICESat-2 QL datasets were created to fill a need for low latency data for mapping sea ice, surface water extent, and vegetation height. This need was identified through the SNWG’s 2018 biennial assessment survey. The purpose of the SNWG biennial assessments is to document and communicate satellite Earth-observing needs to NASA and other space-based Earth observation providers regarding the data each agency needs to accomplish its objectives. The assessments also help identify potential data gaps in the current NASA program of record along with possible gaps in datasets that meet agency needs.
The SNWG MO is part of NASA’s Interagency Implementation and Advanced Concepts Team (IMPACT), which is a component of NASA’s Earth Science Data Systems (ESDS) Program. The SNWG MO works in coordination with the larger SNWG initiative of the U.S. Group on Earth Observations (USGEO) and serves as a data liaison between NASA’s Earth Science Data and Information System (ESDIS) Project and external federal agencies. The SNWG SEP brings together capabilities from across NASA and other partner organizations to assist with SNWG product training and outreach.
The QL datasets are available much faster than the typical 45-day processing period required for ICESat-2 standard datasets. This reduction in latency is achieved by using rapid orbit determinations that result in larger geolocation uncertainties (up to 100 m) on the ground and increase position uncertainties related to the retrieval of surface height. While not intended for scientific research, these rapidly available datasets are an excellent resource for a quick look at an ongoing event or for decision making.
Standard ICESat-2 data, on the other hand, are research-quality datasets that are based on the best possible solutions for the position of the observatory and have a geolocation uncertainty of less than 5 m. Since the QL and standard datasets are equivalent except for their assumptions about the observatory position and resulting differences in uncertainties, tools developed for use with standard ICESat-2 products also will support ICESat-2 QL datasets.
Explore ICESat-2 QL datasets:
