OLCI/Sentinel-3A L1 Reduced Resolution Top of Atmosphere Reflectance

The OLCI/Sentinel-3A L1 Reduced Resolution Top of Atmosphere Reflectance, S3A_OL_1_ERR is generated from the data aquired by the Ocean and Land Colour Instrument (OLCI) on board European Earth Observation satellite mission, SENTINEL-3. The OLCI is a push-broom imaging spectrometer that measures solar radiation reflected by the Earth at a ground spatial resolution of around 300m, over all surfaces, in 21 spectral bands. OLCI is based on the imaging design of ENVISAT's Medium Resolution Imaging Spectrometer (MERIS). It has a 1270km wide swath.

For more information about the instrument and the mission, visit "Sentinel Online" at https://sentinel.esa.int/web/sentinel/home.

The S3A_OL_1_ERR is a Level-1B product. This is composed of an information package map, called a manifest, 22 measurement data files, and seven annotation data files. The 21 measurement data files (one for each band) consist of Top Of Atmosphere (TOA) radiances, calibrated to geophysical units (W.m-2. sr-1 Micro meter-1), georeferenced onto the Earth's surface, and spatially resampled onto an evenly spaced grid. Seven annotation files provide information on illumination and observation geometry, environment data (meteorological data) and quality and classification flags. Both measurement data files and annotation data files are written in netCDF 4 format. The manifest file is in XML format and contains metadata associated with the instrument and the processing. The S3A_OL_1_EFR is generated in Earth Observation (EO) processing mode and all parameters in this product are provided for each re-gridded pixel on the product image and for each removed pixel.

The OL_1_EFR product package is described below:

Element name Description
Manifest.safe SENTINEL-SAFE product manifest
Oa##_radiance.nc Radiance for OLCI acquisition bands 01 to 21
Time_coordinates.nc Time stamp annotations
Geo_coordinates.nc High resolution georeferencing data
Quality_flags.nc Classification and quality flags
Tie_geo_coordinates.nc Low resolution georeferencing data
Tie_geometries.nc Sun and view angles
Tie_meteo.nc ECMWF meteorology data
Instrument_data.nc Instrument data

note: Oa## represents all the OLCI channels (Oa1 to Oa21).

For more information about the product, read the SENTINEL-3 OLCI User Guide at https://sentinel.esa.int/web/sentinel/user-guides/sentinel-3-olci

欧洲地球观测卫星任务 SENTINEL-3 载有海洋与陆地颜色仪（OLCI）所获取的数据生成的 OLCI/Sentinel-3A L1 减少分辨率大气顶面反射率数据集 S3A_OL_1_ERR。OLCI 是一种推帚式成像光谱仪，能够测量地球表面在约 300m 的地面空间分辨率下，21 个光谱带内反射的太阳辐射。OLCI 的成像设计基于 ENVISAT 的中分辨率成像光谱仪（MERIS）。其扫描宽度达到 1270km。有关仪器和任务更详细的信息，请访问“Sentinel Online”网站，链接为 https://sentinel.esa.int/web/sentinel/home。S3A_OL_1_ERR 是一级 B 级产品，由一个信息包地图，即清单，22 个测量数据文件和 7 个注释数据文件组成。21 个测量数据文件（每个光谱带一个）包含大气顶面（TOA）辐射度，校准至地球物理单位（W·m^-2·sr^-1·μm^-1），并地理编码至地球表面，并在均匀间隔的网格上进行空间重采样。7 个注释文件提供了关于照明和观测几何形状、环境数据（气象数据）以及质量和分类标记的信息。测量数据文件和注释数据文件均以 netCDF 4 格式编写。清单文件为 XML 格式，包含与仪器和数据处理相关的元数据。S3A_OL_1_EFR 在地球观测（EO）处理模式下生成，此产品中的所有参数均提供于产品图像上的每个重采样的像素和每个移除的像素。以下是 OL_1_EFR 产品包的描述：

元素名称 描述
Manifest.safe SENTINEL-SAFE 产品清单
Oa##_辐射度.nc OLCI 获取波段 01 至 21 的辐射度
时间坐标.nc 时间戳注释
地理坐标.nc 高分辨率地理编码数据
质量标记.nc 分类和质量标记
连接地理坐标.nc 低分辨率地理编码数据
连接几何形状.nc 太阳和视角度
连接气象数据.nc ECMWF 气象数据
仪器数据.nc 仪器数据

注：Oa## 代表所有 OLCI 通道（Oa1 至 Oa21）。有关产品更详细的信息，请参阅 SENTINEL-3 OLCI 用户指南，链接为 https://sentinel.esa.int/web/sentinel/user-guides/sentinel-3-olci。