IceBridge Preliminary ATM L1B Elevation and Return Strength, Version 1

This data set contained preliminary spot elevation measurements of Arctic sea ice and Greenland ice surface for four days in April 2019, acquired using the NASA Airborne Topographic Mapper (ATM) instrumentation. The data were collected as part of Operation IceBridge funded aircraft survey campaigns. Note: These data were released solely to assess and validate the performance of the ATLAS/ICESat-2 instrument and algorithm. They were not subjected to the same refinement and quality control measures as the IceBridge ATM L1B Elevation and Return Strength (ILATM1B) product and may have contained errors. Once NSIDC released the final ILATM1B data in March 2021, these preliminary data were retired and are no longer available for download.本数据集包含2019年4月为期四天的北极海冰与格陵兰冰盖表面点位初步高程测量数据，采用美国国家航空航天局（NASA）机载地形测绘仪（Airborne Topographic Mapper，ATM）设备采集。该数据为“冰桥行动”（Operation IceBridge）资助的航空勘测任务的一部分。 注意：本数据集仅用于评估与验证ATLAS/ICESat-2仪器及算法的性能，未经过与冰桥行动ATM L1B高程与回波强度（ILATM1B）数据集产品相同的精细化处理与质量控制流程，可能存在误差。2021年3月国家冰雪数据中心（National Snow and Ice Data Center，NSIDC）发布最终版ILATM1B数据集后，本初步数据集即被退役，不再提供下载。