GHRSST Level 2P Global 1m Sea Surface Temperature from the Advanced Very High Resolution Radiometer (AVHRR) on the MetOp-B satellite produced by NAVO for 2017-05-20 (NCEI Accession 0164117)

A global Group for High Resolution Sea Surface Temperature (GHRSST) Level 2P dataset based on multi-channel sea surface temperature (SST) retrievals generated in real-time from the Advanced Very High Resolution Radiometer (AVHRR) on the European Meteorological Operational-A (MetOp-A; launched 19 Oct 2006) ) satellite produced and used operationally in oceanographic analyses and forecasts by the US Naval Oceanographic Office (NAVO). The MetOp satellite program is a European undertaking providing weather data services for monitoring climate and improving weather forecasts. It was jointly established by the European Space Agency (ESA) and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) with a contribution by the US National Oceanic and Atmospheric Administration (NOAA) of an AVHRR sensor identical to those flying on the family of Polar Orbiting Environmental Satellites (POES). AVHRR instruments measure the radiance of the Earth in 5 (or 6) relatively wide spectral bands. The first two are centered around the red (0.6 micrometer) and near-infrared (0.9 micrometer) regions, the third one is located around 3.5 micrometer, and the last two sample the emitted thermal radiation, around 11 and 12 micrometers, respectively. The legacy 5 band instrument is known as AVHRR/2 while the more recent version, the AVHRR/3 (first carried on the NOAA-15 platform), acquires data in a 6th channel located at 1.6 micrometer. Typically the 11 and 12 micron channels are used to derive SST sometimes in combination with the 3.5 micron channel. The MetOp-A platform is sun synchronous generally viewing the same earth location twice a day (latitude dependent) due to the relatively large AVHRR swath of approximately 2400 km. The highest ground resolution that can be obtained from the current AVHRR instruments is 1.1 km at nadir. This particular dataset is produced from Global Area Coverage (GAC) data that are derived from an on-board sample averaging of the full resolution global AVHRR data. Four out of every five samples along the scan line are used to compute on average value and the data from only every third scan line are processed, yielding an effective 4 km resolution at nadir. Further binning and averaging of these pixels results in a final dataset resolution of 8.8 km.

本数据集为全球高分辨率海表温度（Group for High Resolution Sea Surface Temperature, GHRSST）体系下的2P级数据集，基于多通道海表温度（sea surface temperature, SST）反演结果构建，该反演结果由搭载于欧洲气象业务-A卫星（European Meteorological Operational-A, MetOp-A；2006年10月19日发射）的先进甚高分辨率辐射计（Advanced Very High Resolution Radiometer, AVHRR）实时生成，并由美国海军海洋学办公室（US Naval Oceanographic Office, NAVO）开展业务化海洋学分析与预报工作时生产与使用。MetOp卫星计划是一项欧洲牵头的项目，旨在提供气象数据服务以监测气候并优化天气预报。该计划由欧洲空间局（European Space Agency, ESA）与欧洲气象卫星开发组织（European Organisation for the Exploitation of Meteorological Satellites, EUMETSAT）联合组建，美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration, NOAA）提供了与极轨环境卫星（Polar Orbiting Environmental Satellites, POES）系列搭载的同款AVHRR传感器。AVHRR仪器可测量地球在5（或6）个相对宽谱波段的辐射亮度，其中前两个波段的中心波长分别位于红光（0.6微米）与近红外（0.9微米）区域，第三个波段中心约为3.5微米，最后两个波段分别采样11微米和12微米附近的热辐射。传统5波段机型被称为AVHRR/2，而最新版本AVHRR/3（首次搭载于NOAA-15平台）新增了1.6微米的第6通道。实际海表温度反演通常利用11和12微米波段，有时也会结合3.5微米波段。MetOp-A卫星为太阳同步轨道，由于AVHRR的幅宽约为2400公里，其通常每日可两次观测同一地球位置（观测频次随纬度变化）。当前AVHRR仪器在星下点可获得的最高地面分辨率为1.1公里。本数据集源自全球区域覆盖（Global Area Coverage, GAC）数据，该数据通过对全分辨率全球AVHRR数据进行星上采样平均得到：扫描线上每5个采样点中选取4个计算平均值，且仅处理每第三条扫描线的数据，最终在星下点得到的有效分辨率为4公里。进一步对这些像素进行分箱与平均处理后，最终数据集的分辨率为8.8公里。