GHRSST NOAA/STAR Metop-A AVHRR FRAC ACSPO v2.80 0.02 L3U Dataset (GDS version 2)

This L3U (Level 3 Uncollated) dataset contains global daily Sea Surface Temperature (SST) on a 0.02 degree grid resolution. It is produced by the National Oceanic and Atmospheric Administration (NOAA) Advanced Clear Sky Processor for Ocean (ACSPO) using L2P (Level 2 Preprocessed) product acquired from the Meteorological Operational satellite A (Metop-A) Advanced Very High Resolution Radiometer 3 (AVHRR/3) in Full Resolution Area Coverage (FRAC) mode as input. It is distributed as 10-minute granules in netCDF-4 format, compliant with the Group for High Resolution Sea Surface Temperature (GHRSST) Data Specification version 2 (GDS2). There are 144 granules per 24-hour interval. Fill values are reported in all invalid pixels, including land pixels with >5 km inland. For each valid water pixel (defined as ocean, sea, lake or river), and up to 5 km inland, the following major layers are reported: SSTs and ACSPO clear-sky mask (ACSM; provided in each grid as part of l2p_flags, which also includes day/night, land, ice, twilight, and glint flags). Only input L2P SSTs with QL=5 were gridded, so all valid SSTs are recommended for the users. Per GDS2 specifications, two additional Sensor-Specific Error Statistics layers (SSES bias and standard deviation) are reported in each pixel with valid SST. Ancillary layers include wind speed and ACSPO minus reference Canadian Meteorological Centre (CMC) Level 4 (L4) SST. The ACSPO Metop-A AVHRR FRAC L3U product is monitored and validated against iQuam in situ data (Xu and Ignatov, 2014) in the NOAA SST Quality Monitor (SQUAM) system (Dash et al, 2010). SST imagery and clear-sky mask are evaluated, and checked for consistency with L2P and other satellites/sensors SST products, in the NOAA ACSPO Regional Monitor for SST (ARMS) system. More information about the dataset is found at AVHRRF_MA-STAR-L2P-v2.80 and in Pryamitsyn et al. (2021).

L3U（Level 3 Uncollated，未整理三级）数据集包含0.02度网格分辨率下的全球逐日海表温度（Sea Surface Temperature, SST）。该数据集由美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration, NOAA）的海洋先进晴空处理器（Advanced Clear Sky Processor for Ocean, ACSPO）生成，其输入数据为取自气象业务卫星A（Meteorological Operational satellite A, Metop-A）的甚高分辨率辐射计3（Advanced Very High Resolution Radiometer 3, AVHRR/3）在全分辨率区域覆盖（Full Resolution Area Coverage, FRAC）模式下获取的L2P（Level 2 Preprocessed，二级预处理）产品。数据集以netCDF-4格式的10分钟间隔数据粒分发，每24小时时段内包含144个数据粒，且符合高精度海表温度小组（Group for High Resolution Sea Surface Temperature, GHRSST）制定的数据规范2.0版本（GDS2）。所有无效像元（包括距内陆超过5千米的陆地区域像元）均会填充缺失值。对于每个有效水体像元（定义为海洋、海域、湖泊或河流，且距内陆不超过5千米），将输出以下主要图层：海表温度（SST）以及ACSPO晴空掩码（ACSPO Clear-sky Mask, ACSM）——该掩码作为l2p_flags的一部分存储于每个网格中，同时包含昼夜、陆地、海冰、暮光以及太阳耀斑标识。仅将质量等级QL=5的二级预处理SST数据进行网格化处理，因此所有有效SST数据均可供用户使用。根据GDS2规范，每个包含有效SST的像元还将输出两个额外的传感器特定误差统计（Sensor-Specific Error Statistics, SSES）图层，即偏差值与标准差值。辅助图层包括风速以及ACSPO反演SST与加拿大气象中心（Canadian Meteorological Centre, CMC）四级（Level 4, L4）参考SST的差值。ACSPO Metop-A AVHRR FRAC L3U产品通过NOAA SST质量监测（SST Quality Monitor, SQUAM）系统（Dash et al, 2010），以iQuam原位观测数据（Xu and Ignatov, 2014）作为参考进行监测与验证。SST影像与晴空掩码将在NOAA ACSPO海表温度区域监测（ACSPO Regional Monitor for SST, ARMS）系统中进行评估，并与二级预处理产品及其他卫星/传感器的SST产品进行一致性校验。有关该数据集的更多信息可查阅AVHRRF_MA-STAR-L2P-v2.80以及Pryamitsyn等人（2021）的研究文献。