NASA’s Ice, Cloud, and land Elevation Satellite-2, ICESat-2, carries the Advanced Topographic Laser Altimeter System, ATLAS, which sends 10,000 laser pulses per second towards Earth and records individual photons reflected back to its telescope. The volume of data produced by the instrument, nearly a TB of data every day, presents a challenges for the user wishing to explore and do quick analysis on the data. Although NSIDC, the data center responsible for archiving and distributing ICESat-2 data, provides services such as browse and spatial, temporal and parameter subsetting on the data, these are not necessarily conducive to exploratory work. OpenAltimetry, a collaborative project between NSIDC and the San Diego Supercomputer Center at the University of California, San Diego, has created an online platform that allows users to quickly view photon clouds, or waveform energy profiles in the case of ICESat/GLAS, the predecessor mission to ICESat-2/ATLAS, for any time and location of interest to the user, as well as the surface-specific elevations from the higher level ATLAS products. OpenAltimetry emphasizes ease-of-use and rapid response times. NASA’s Ice, Cloud, and land Elevation Satellite-2, ICESat-2, carries the Advanced Topographic Laser Altimeter System, ATLAS, which sends 10,000 laser pulses per second towards Earth and records individual photons reflected back to its telescope. The volume of data produced by the instrument, nearly a TB of data every day, presents a challenges for the user wishing to explore and do quick analysis on the data. Although NSIDC, the data center responsible for archiving and distributing ICESat-2 data, provides services such as browse and spatial, temporal and parameter subsetting on the data, these are not necessarily conducive to exploratory work. OpenAltimetry, a collaborative project between NSIDC, Scripps Institution of Oceanography and the San Diego Supercomputer Center at the University of California San Diego, has created an online platform that allows users to quickly view photon clouds, or waveform energy profiles in the case of ICESat/GLAS, the predecessor mission to ICESat-2/ATLAS, for any time and location of interest to the user, as well as the surface-specific elevations from the higher level ATLAS products. OpenAltimetry emphasizes ease-of-use and rapid response times. A user can do more in depth data analysis on a Jupyter notebook invoked through OpenAltimetry’s map-based interface, thus providing a full data analysis stack that lives in the cloud and enables scientists to do their work without investing a lot of time thinking about dependencies and deployments.

We use ICESat-2 laser altimetry crossovers and repeat tracks collected over the North Slope of Alaska to estimate elevation changes due to the deformation of seasonally freezing and thawing permafrost. We compare these measurements with a time series of surface deformation from Sentinel-1 interferometric synthetic aperture radar (InSAR) and demonstrate agreement between these independent observations of surface deformation. Both methods resolve pronounced surface subsidence during the 2019 thaw season within the 2007 Anaktuvuk River fire scar. A temporal relationship between measured surface subsidence/uplift and changes in normalized annual degree days is observed, consistent with the thermodynamically driven seasonal freezing and thawing of the active layer. We discuss optimal strategies of post-processing ICESat-2 data for permafrost applications, as well as the future potential of joint ICESat-2 and InSAR investigations of permafrost surface dynamics.

We analyze 580 continuous GPS stations in California from 5 analysis centers to quantify the uncertainty in published velocities and develop a composite velocity for each station. The horizontal positions are similar but the reported velocity varies by time series algorithm. Vertical rates for individual stations differ up to 5 mm/yr, with systematic differences in some areas. The published uncertainties show variability between analysis centers and are underreported, suggesting these formal errors do not reflect the true velocity uncertainties. Differences by a factor of 4 are found in the vertical and is comparable to deformation rates. An interpolated ensemble vertical velocity field is developed and regions with the highest rates of uplift or subsidence correspond to the largest variance in velocities between analysis centers, but high station density can reduce these uncertainties. Applications that rely on sub-centimeter GPS accuracy should consider the inherent uncertainty in published vertical velocity rate estimates.