MODIS/Aqua Level 1B Subsampled Calibrated Radiance 5Km - NRT

This Near Real Time (NRT) data type (MYD02SSH) is a subsample from the MODIS Level 1B 1-km data. Every fifth pixel is taken from the MYD021KM product and written out to MYD02SSH. The subsampling starts at the third frame, and at the third line. Here, "frame" and "line" are naming conventions for pixels along and across the scan, respectively. Since MYD02SSH is a subsampled Level 1B , many things from the Level 1B documentation apply as well. That is, the MYD02SSH data productcontains calibrated and geolocated at-aperture radiances for 36 bands generated from MODIS Level 1A scans of raw radiance (MOD 01). The radiance units are in W/(m ^2 um sr). Additional data are provided including quality flags, error estimates and calibration data. Visible, shortwave infrared (SWIR), and Near Infrared (NIR) measurements are made during daytime only, while radiances for Thermal Infrared (TIR) are measured continuously.As it's parent, the MYD02SSH is in HDF-EOS format, and all metadata structures and names are preserved for better convenience. However, some relevant changes are made where appropriate, e.g. the dimension mappings are updated to reflect the new one-to-one correspondance between the data and geolocations. The latter is one of the most important differences: in the MYD02SSH, there is no offset between data and geolocation pixels. The spatial coverage is almost similar to that from MYD021KM (nominally it is 2330 by 2030 km, cross-track by along-track, respectively). The MYD02SSH is produced continuously, and thus the processing provides 2-day repeat observations of the Earth with a repeat orbitpattern every 16 days.The shortname for this product is MYD02SSH

近实时（Near Real Time, NRT）数据类型MYD02SSH是从中分辨率成像光谱仪（Moderate Resolution Imaging Spectroradiometer, MODIS）1级B型1千米分辨率数据中提取的子采样数据集。从MYD021KM产品中每5个像素选取1个，生成MYD02SSH数据集。子采样起始于第3帧与第3行，此处“帧”与“行”分别为扫描方向与跨扫描方向像素的命名约定。由于MYD02SSH属于子采样后的1级B型数据集，因此1级B型数据集文档中的多数内容同样适用于本产品。具体而言，MYD02SSH数据集包含从MODIS 1级A型原始辐射扫描数据（MOD 01）生成的36个波段的定标后孔径辐射亮度与地理定位信息，辐射亮度单位为W/(m²·μm·sr)。数据集还附带质量标志、误差估计值与定标数据。可见光、短波红外（Shortwave Infrared, SWIR）与近红外（Near Infrared, NIR）仅在日间进行观测，而热红外（Thermal Infrared, TIR）辐射亮度则持续采集。与母产品一致，MYD02SSH采用HDF-EOS格式存储，为便于使用，所有元数据结构与命名均予以保留。但针对实际需求进行了必要调整，例如更新了维度映射关系，以反映数据与地理定位像素间全新的一一对应关系。后者为该产品最显著的差异之一：MYD02SSH中数据像素与地理定位像素之间不存在偏移。其空间覆盖范围与MYD021KM基本一致，名义上的跨轨与沿轨尺寸分别为2330千米与2030千米。MYD02SSH为持续生产产品，因此其处理流程可实现每2天对地球的重复观测，并以16天为一个重复轨道周期。本产品的短名称为MYD02SSH。