GHRSST v2 Level 3U Global Skin Sea Surface Temperature from the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite created by the NOAA Advanced Clear-Sky Processor for Ocean (ACSPO) for 2017-06-20 (NCEI Accession 0163568)

The ACSPO VIIRS L3U (Level 3 Uncollated) product is a gridded version of the ACSPO VIIRS L2P product available here http://podaac.jpl.nasa.gov/dataset/VIIRS_NPP-OSPO-L2P-v2.4. Data files are 10min granules in netcdf4 format compliant with the GHRSST Data Specification version 2 (GDS2). There are 144 granules per 24hr interval, with a total data volume of 1GB/day. Fill values are reported at all invalid pixels, including pixels at >5 km inland. For each valid water pixel (defined as ocean, sea, lake or river, and up to 5 km inland), the following layers are reported: SSTs, 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), NCEP wind speed, and ACSPO SST minus reference (Canadian Met Centre 0.2deg L4 SST; available at http://podaac.jpl.nasa.gov/dataset/CMC0.2deg-CMC-L4-GLOB-v2.0). Only 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. The ACSPO VIIRS L3U product is monitored and validated against in situ data (Xu and Ignatov, 2014) in SQUAM (Dash et al, 2010).ACSPO VIIRS L3U（三级未整理，Level 3 Uncollated）产品是ACSPO VIIRS L2P产品的网格化版本，其原始L2P产品可访问于http://podaac.jpl.nasa.gov/dataset/VIIRS_NPP-OSPO-L2P-v2.4。该产品的数据文件为10分钟数据粒，采用符合全球高分辨率海表温度研究组（Group for High Resolution Sea Surface Temperature, GHRSST）数据规范第2版（GDS2）标准的netCDF4格式存储。每24小时时段内包含144个数据粒，单日总数据量约为1GB。所有无效像元均会填充缺失值，其中包括距离内陆5千米以上的区域像元。针对每个有效水体像元（定义为海洋、近海、湖泊或河流，且距内陆不超过5千米），数据集提供以下数据层：海表温度（Sea Surface Temperature, SST）、ACSPO晴空掩码（ACSM，作为l2p_flags的一部分存储于每个网格中，该标志位同时涵盖昼夜标识、陆地标识、海冰标识、暮光标识及太阳耀斑标识）、美国国家环境预报中心（National Centers for Environmental Prediction, NCEP）风速数据，以及ACSPO反演海表温度与参考海表温度的差值（参考海表温度为加拿大气象中心发布的0.2°分辨率四级海表温度产品，可访问于http://podaac.jpl.nasa.gov/dataset/CMC0.2deg-CMC-L4-GLOB-v2.0）。仅将质量等级（QL）为5的L2P海表温度数据进行网格化处理，因此所有有效海表温度数据均可供用户使用。根据GDS2规范，每个包含有效海表温度的像元还会额外提供两个传感器特定误差统计（Sensor-Specific Error Statistics, SSES）数据层，分别为偏差值与标准差。ACSPO VIIRS L3U产品已通过原位观测数据（Xu与Ignatov，2014）并采用SQUAM工具（Dash等，2010）完成监测与验证。