Latency Descriptions of ICESat-2 Products
ICESat-2 data collections consist of global altimetry products derived from the Advanced Topographic Laser Altimeter System (ATLAS) instrument aboard the Ice, Cloud and land Elevation Satellite-2 (ICESat-2). The ATLAS/ICESat-2 L1B Converted Telemetry Data (ATL02) becomes available ~3 days after collection, then is further processed into a wide range of products that have varied delivery times. The latencies noted below apply to the ATLAS/ICESat-2 L2A Global Geolocated Photon Data (ATL03) data set and beyond. The full list of ICESat-2 products can be seen here: https://nsidc.org/data/icesat-2/products
The processing time needed for many of these products is on the order of a month. To satisfy the need for data that are delivered with a lower lag time from data collection to data delivery, “Quick Looks” and “Low Latency” products have been developed.
ICESat-2 product latency, quality and archiving
Below is a chart comparing the latency, uncertainties, and archiving of standard products versus fast-tracked products. This table includes a general sense of uncertainties calculated from validation by external data sets that can vary widely based on surface types and the algorithms used to analyze them.
| Standard Product | Low Latency | Quick Looks | |
|---|---|---|---|
| Latency time | 2-3 months | 4-7 days | 3-5 days |
| Vertical uncertainty* | ~ 10-50 cm | ± ~ 5 cm (3 std dev) | ± 1.25 m plus 2.7 m bias |
| Geolocation uncertainty* | 3.5 m ± 2.1 m | ± ~ 150 cm | ± 100 m |
| Archive time | Until new version is available + 6 month overlap | 180 days | Until standard product is available |
Available fast-tracked products
Not all of the ICESat-2 data sets have associated fast-tracked products. Availability is shown in the following table as well as described in the graphic on the products overview page.
Standard Data Set | Quick Look (QL) | Low Latency (LL) |
|---|---|---|
ATLAS/ICESat-2 L2A Global Geolocated Photon Data (ATL03) | x | ✔️ |
ATLAS/ICESat-2 L2A Normalized Backscatter Profiles (ATL04) | x | x |
ATLAS/ICESat-2 L3A Land Ice Height (ATL06) | x | late 2026 / early 2027 |
ATLAS/ICESat-2 L3A Sea Ice Height (ATL07) | ✔️ | late 2026 / early 2027 |
ATLAS/ICESat-2 L3A Land and Vegetation Height (ATL08) | ✔️ | late 2026 / early 2027 |
ATLAS/ICESat-2 L3A Calibrated Backscatter Profiles and Atmospheric Layer Characteristics (ATL09) | ✔️ | late 2026 / early 2027 |
ATLAS/ICESat-2 L3A Sea Ice Freeboard (ATL10) | ✔️ | late 2026 / early 2027 |
ATLAS/ICESat-2 L3A Ocean Surface Height (ATL12) | x | x |
ATLAS/ICESat-2 L3A Along Track Inland Surface Water Data (ATL13) | ✔️ | late 2026 / early 2027 |
ATLAS/ICESat-2 L3B Daily and Monthly Gridded Sea Ice Freeboard (ATL20) | ✔️ | late 2026 / early 2027 |
References:
Magruder, L., Brunt, K., Neumann, T., Klotz, B., & Alonzo, M. (2021). Passive ground-based optical techniques for monitoring the on-orbit ICESat-2 altimeter geolocation and footprint diameter. Earth and Space Science, 8, e2020EA001414. https://doi.org/10.1029/2020EA001414
Magruder, L.A., Farrell, S.L., Neuenschwander, A. et al. Monitoring Earth’s climate variables with satellite laser altimetry. Nat Rev Earth Environ 5, 120–136 (2024). https://doi.org/10.1038/s43017-023-00508-8
Neuenschwander, A., Guenther, E., White, J. C., Duncanson, L. & Montesano, P. Validation of ICESat-2 terrain and canopy heights in boreal forests. Remote Sens. Environ. 251, 112110 (2020). https://doi.org/10.1016/j.rse.2020.112110