On-orbit performance analyses of the ATL03 geolocated photon cloud product from ICESat-2

NASA's Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) mission measures the elevation of Earth's ice sheets, sea ice freeboard, water surfaces, and vegetation canopies with the Advanced Topographic Laser Altimeter System (ATLAS), a 6-beam photon-counting laser altimeter. The ICESat-2 ATL03 data product is the primary source of photon information required by higher level products, along with the Calibrated Backscatter Profiles and Atmospheric Layer Characteristics data product, ATL09. ATL03 provides time-tagged, geolocated ellipsoidal photon heights for events downlinked from ATLAS, as well as confidence levels categorizing each photon event as signal or background for land, ocean, sea ice, land ice, and inland water surface types. Presented here are analyses of on-orbit performance of the ATL03 product including ATLAS transmit and return pulse shapes and radiometric performance over various surface types, assessments of the signal finding algorithm representation of the return pulse shape and signal photon rates, and preliminary improvements to the signal finding algorithm to prevent misclassification of clouds as surface, for consideration in a future data release.