ICESat-2 Atmospheric Channel Description, Data Processing and First Results
Journal Article
Overview
abstract
The Advanced Topographic Laser Altimeter System (ATLAS) was launched; aboard the Ice Cloud and land-Elevation Satellite-2 (ICESat-2) satellite; in September 2018. ATLAS is a single wavelength (532 nm) lidar system; designed to acquire high resolution measurements of the earth’s surface; while also obtaining atmospheric backscatter from molecules, clouds, and; aerosols. Because ATLAS is optimized for altimetry, the atmospheric data; acquired is unique in many respects and requires non-standard analysis; techniques. For example, the high repetition rate laser limits the; vertical extent of the profiles to just 14 km and causes atmospheric; scattering from above 15 km to be added to the scattering in the lower 0; -14 km profile. In addition, the limited vertical range of the acquired; profiles renders it difficult to compute the magnitude of the solar; background and hinders the application of standard calibration; techniques. Despite these limitations, techniques have been developed to; successfully produce data products that have value to the atmospheric; community for cloud and aerosol research and are currently available at; the National Snow and Ice Data Center (NSIDC). In this paper we describe; the ICESat-2 atmospheric channel and the methods used to process the; ATLAS raw photon count data to obtain calibrated backscatter and higher; level products such as layer heights and type, blowing snow, column; optical depth and apparent surface reflectance.
