GHRSST Level 2P Regional 1m Sea Surface Temperature from the Advanced Very High Resolution Radiometer (AVHRR) on the NOAA-19 satellite produced by NAVO for 2017-04-02 (NCEI Accession 0163137)

A regional 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 NOAA-19 platform (launched 6 Feb 2009) produced and used operationally in oceanographic analyses and forecasts by the US Naval Oceanographic Office (NAVO). The AVHRR is a space-borne scanning sensor on the National Oceanic and Atmospheric Administration (NOAA) family of Polar Orbiting Environmental Satellites (POES) having a operational legacy that traces back to the Television Infrared Observation Satellite-N (TIROS-N) launched in 1978. 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 NOAA platforms are 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. AVHRR data are acquired in three formats: High Resolution Picture Transmission (HRPT), Local Area Coverage (LAC), and Global Area Coverage (GAC). HRPT data are full resolution image data transmitted to a ground stations as they are collected. LAC are also full resolution data, but the acquisition is prescheduled and recorded with an on-board tape recorder for subsequent transmission during a station overpass. GAC data provide daily subsampled global coverage recorded on tape recorders and then transmitted to a ground station. This particular dataset is derived from LAC data. Further binning and averaging of the 1.1 km LAC pixels results in a final dataset resolution of 2.2 km. The coverage of the LAC data can vary but generally contains scenes over the oceans adjacent to Australia and the North Indian Ocean.本数据集为基于多通道海表温度（sea surface temperature, SST）反演结果生成的区域级高分辨率海表温度工作组（Group for High Resolution Sea Surface Temperature, GHRSST）2P级数据集，其数据源自2009年2月6日发射的NOAA-19卫星平台上搭载的先进甚高分辨率辐射计（Advanced Very High Resolution Radiometer, AVHRR）的实时反演结果，由美国海军海洋学办公室（US Naval Oceanographic Office, NAVO）生成并业务化应用于海洋学分析与预报工作。先进甚高分辨率辐射计是美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration, NOAA）极轨环境卫星（Polar Orbiting Environmental Satellites, POES）系列搭载的星载扫描传感器，其业务化发展历史可追溯至1978年发射的泰罗斯-N系列卫星（Television Infrared Observation Satellite-N, TIROS-N）。AVHRR仪器可测量地球在5（或6）个相对较宽光谱波段的辐射亮度，其中前两个波段分别以红光（0.6微米）和近红外（0.9微米）波段为中心，第三个波段中心位于3.5微米附近，最后两个波段则分别采样11微米和12微米附近的热辐射。传统的5波段仪器被称为AVHRR/2，而最新的AVHRR/3（首次搭载于NOAA-15卫星平台）新增了1.6微米的第6通道以获取观测数据。通常可利用11微米与12微米波段反演海表温度，有时也会结合3.5微米波段提升反演精度。NOAA卫星平台采用太阳同步轨道，由于AVHRR的刈幅宽度约为2400千米，因此一般可每日两次观测同一地球位置（具体观测频次取决于纬度）。当前AVHRR仪器可获得的最高地面分辨率为星下点处1.1千米。AVHRR数据共有三种传输格式：高分辨率图像传输（High Resolution Picture Transmission, HRPT）、局地区域覆盖（Local Area Coverage, LAC）以及全球区域覆盖（Global Area Coverage, GAC）。其中HRPT数据为全分辨率图像数据，在采集完成后直接传输至地面站；LAC同样为全分辨率数据，但需预先规划采集计划，并通过星载磁带记录仪录制，待地面站过境时再行传输；GAC数据可提供每日降采样后的全球覆盖数据，录制于磁带记录仪后再传输至地面站。本数据集的原始数据源自LAC格式数据，通过对1.1千米分辨率的LAC像素进行进一步分箱与平均处理后，最终得到的数据集分辨率为2.2千米。LAC数据的覆盖范围存在一定波动，但通常包含澳大利亚周边海域以及北印度洋的观测场景。