ICESat-2 Ground Tracks
A note for end users:
The KMLs provided below are estimates of locations and times of the ICESat-2 reference ground track and beams. Prior to April 1 2019, we were not pointing at our RGT and as such, data collected during that time was not along planned RGTs and these KMLs should not be used in an attempt to sync with data collected between October 2018 and April 1, 2019. The geolocation information provided in ICESat-2 data available for download at NSIDC reflects where data was actually collected.
Below are links to the kmz files for all of the laser tracks over each 91-day repeat period. Kmz Files for other areas upcoming or on request. Note that the locations and times are estimates, but should be correct to within a few minutes in time and better than 100m in the predicted locations.
Overall Mission Orbits
These files contain the nominal mission orbits and beam locations, the files have seven tracks per orbit: one for each of the six beams of ICESat-2, and the seventh for the Reference Ground Track (RGT). The RGT is an imaginary line through the six-beam pattern that is handy for getting a sense of where the orbits fall on Earth, and which the mission uses to point the observatory. However, the six tracks for the six beams are our best estimate of where the beams will actually fall on Earth’s surface.
Western Hemisphere Ground Tracks
Eastern Hemisphere Ground Tracks
Time Specific Orbits
These files contain the reference ground track time (UTC) and locations for specific date ranges. Updated KML files have been posted to this website containing individual files for each RGT with a date and time stamp posted every 420 kilometers along-track (roughly 1 minute of flight time in between each point). Our first RGT is #234; this is where the time series begins. The date of each RGT is in the file name, so the user can easily ascertain where and when ICESat-2 will be on a particular day.
Cycle 1: October 13 - December 28, 2018
Cycle 2: December 28 (2018) - March 29, 2019
Cycle 3: March 29 - June 28, 2019
Cycle 4: July 9 - September 26, 2019 -- ICESat-2 was in safe-hold from June 26 through July 9, 2019. ATLAS was off during this time, so we were not collecting data or pointing at our reference ground track. We resumed RGT pointing shortly after the laser was turned back on, and on August 1 2019, we began vegetation off-pointing at RGT 518.
Cycle 5: September 26 - December 26, 2019
Cycle 6: December 26, 2019 - March 26, 2020
Cycle 7: March 26, 2020 - June 25, 2020
Cycle 8: June 25, 2020 - September 24, 2020
Cycle 9: September 24, 2020 - December 23, 2020
Cycle 10: December 24, 2020 - March 24, 2021
Cycle 11: March 24, 2021 - June 23, 2021
Cycle 12: June 23, 2021 - September 22, 2021
Cycle 13: September 22, 2021 - December 22, 2021
Cycle 14: December 22, 2021 - March 23, 2022
Cycle 15: March 23, 2022 - June 21, 2022 -- ICESat-2 was in safe-hold from April 4 through April 12, 2022. Data were not collected during this time. We resumed RGT pointing on April 12, and vegetation off-pointing resumed on April 21 at RGT 444.
Cycle 16: June 21, 2022 - September 20, 2022
Cycle 17: September 20, 2022 - December 20, 2022
Cycle 18: December 20, 2022 - March 21, 2023*
Cycle 19: March 21, 2023 - June 20, 2023
Cycle 20: June 20, 2023 - September 19, 2023
Cycle 21: September 19, 2023 - December 18, 2023
* indicates that there is more RGT pointing in these cycles over the northern hemisphere land to observe seasonal snow.
The files below are provisional pointing plans and will have timestamp errors. These should be used for polar planning only. Final plans will differ at mid-latitudes.
Cycle 22: December 18, 2023 - March 18, 2024
These files are posted at a fairly low resolution in order to make the file size manageable, with one point approximately every 7 kilometers.
Over the polar areas and oceans, ICESat-2 will repeat its ground tracks every 91 days as it orbits; over land the satellite will point slightly off the RGT to measure more of Earth’s forests. The transitions between repeat-track pointing and off-pointing are included in these ground tracks. Near the poles, the difference between the two is subtle, but it becomes more pronounced near the equator.
- Remember that while these represent the nominal location of the sub-satellite point with associated date/time of the ICESat-2 overpass, the mission requirements are for 45 meter pointing control which currently appears to be met.
Check out the ICESat-2 App to track when and where ICESat-2 will pass over an area on the Earth.
Key ICESat-2/ATLAS Performance Specifications
For detailed information about ICESat-2 and ATLAS specifications, please see Neumann et al., 2019.
|Nominal duration of mission||3 Years|
|Number of beams||6 organized in 3 pairs|
|Footprint size||13 m|
|Field of view||45 m|
|Pulse repetition frequency||10kHz (~0.7m on the ground)|
|Laser wavelength||532 nm|
|Pointing control||45 m|
|Pointing knowledge||6.5 m|
|Single-photon time-of-flight precision||800 ps|
ATLAS expected performance in range using the current best estimates for winter and
Lambertian surface reflectance
N signal photons per shot
N signal photons per shot
|100-shot std dev (weak beam)||100-shot std dev (strong beam)|
|Ice sheet (interior)||0.9 -0.98||0.4 - 3.0||1.6 - 12.0||4 - 9||2 - 4|
|Ice sheet (glaciers)||0.6 - 0.9||0.6 - 1.0||0.6 - 3.9||12 - 29||6 - 14|
|Sea Ice||0.8 - 0.9||0.6 - 2.1||2.3 - 8.5||5 - 8||3 - 4|
* - 0.2
(much higher when specular)
|0.05 - 0.2||0.2 - 1.0||2 - 5||2 - 5|
Orbit and coverage