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 2017-07-08 (NCEI Accession 0164101)

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（Level 3 未整合，Level 3 Uncollated）产品是ACSPO VIIRS L2P产品的网格化版本，该L2P产品可于以下地址获取：http://podaac.jpl.nasa.gov/dataset/VIIRS_NPP-OSPO-L2P-v2.4。数据文件为10分钟粒度的netCDF4格式文件，符合GHRSST数据规范2.0版本（GHRSST Data Specification version 2，简称GDS2）。每24小时时段内包含144个数据粒度，单日总数据量约1GB。所有无效像元（包括距内陆超过5公里的像元）均会填充无效值。针对被定义为海洋、近海、湖泊或河流，且距内陆不超过5公里的有效水像元，将提供以下数据层：海表温度（Sea Surface Temperature，简称SST）、ACSPO晴空掩码（ACSPO clear-sky mask，简称ACSM，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、暮光及太阳耀斑标识）、NCEP风速，以及ACSPO海表温度与参考值的差值（参考值为加拿大气象中心0.2°分辨率L4海表温度产品，可于以下地址获取：http://podaac.jpl.nasa.gov/dataset/CMC0.2deg-CMC-L4-GLOB-v2.0）。仅将质量等级（Quality Level，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。依据GDS2规范，每个包含有效海表温度的像元还将额外提供两个传感器特定误差统计（Sensor-Specific Error Statistics，简称SSES）层：偏差与标准差。ACSPO VIIRS L3U产品会通过原位观测数据进行监测与验证（Xu与Ignatov, 2014），验证框架采用SQUAM（Dash et al, 2010）。