MODIS/Terra Calibrated Radiances 5-Min L1B Swath 250m

The MODIS/Terra Calibrated Radiances 5Min L1B Swath 250m data set contains calibrated and geolocated at-aperture radiances for 2 discrete bands located in the 0.62 to 0.88 micron region of the electromagnetic spectrum. These data are generated from the MODIS Level 1A scans of raw radiance which have been processed to geophysical units of W / (m^2 um sr). Additional data are provided including quality flags, error estimates and calibration data.

Separate L1B products are available for the five 500m resolution channels (MOD02HKM) and the twenty-nine 1km resolution channels (MOD021KM). For the 500m product, there are actually seven channels available since the data from the two 250 m channels have been aggregated to 500m resolution. Similarly, for the 1km product, all 36 MODIS channels are available since the data from the two 250m and five 500m channels have been aggregated into equivalent 1km
pixel values.

Spatial resolution for pixels at nadir is 250 m, degrading to 1.2 km in the along-scan direction and 0.5 km in the along-track direction for pixels located at the scan extremes. A 55 degree scanning pattern at the EOS orbit of 705 km results in a 2330 km orbital swath width and provides global coverage every one to two days. A single MODIS Level 1B 250 m granule will contain a scene built from 203 scans sampled 5416 times in the cross-track direction, corresponding to approximately 5 minutes worth of data; thus 288 granules will be produced per day. Since an individual MODIS scan will contain 40 along-track spatial elements for the 250 m channels, the scene will be composed of (5416 x 8120) pixels, resulting in a spatial coverage of (2330 km x 2040 km). Due to the MODIS scan geometry, there will be increasing scan overlap beyond about 17 degrees scan angle.

The shortname for this product is MOD02QKM and is stored in the Earth Observing System Hierarchical
Data Format (HDF-EOS). A typical file size will be approximately 140 MB and the total daily volume is around 22GB.

Environmental information derived from MODIS L1B measurements will offer a comprehensive and unprecedented look at terrestrial, atmospheric, and ocean phenomenology for a wide and diverse community of users throughout the world.

See the MODIS Characterization Support Team webpage for more C6 product information at:

https://mcst.gsfc.nasa.gov/l1b/product-information

or visit the Science Team homepage at:
https://modis.gsfc.nasa.gov/data/dataprod/

MODIS/Terra校准辐射率5分钟L1B条带250米数据集，包含位于电磁波谱0.62~0.88微米区间的2个离散波段的孔径处校准且已地理定位的辐射率数据。该类数据源自MODIS一级A（Level 1A）扫描的原始辐射率，经处理为W/(m²·μm·sr)的地球物理单位。数据集额外提供质量标志、误差估计值与校准数据。

另有针对5个500米分辨率通道（MOD02HKM）与29个1公里分辨率通道（MOD021KM）的独立L1B产品。对于500米分辨率产品，实际包含7个可用通道，因为两个250米通道的数据已聚合至500米分辨率。同理，1公里分辨率产品可提供全部36个MODIS通道，因为两个250米与5个500米通道的数据已聚合为等效的1公里像元值。

星下点像元的空间分辨率为250米，处于扫描极端位置的像元，沿扫描方向分辨率降至1.2公里，沿轨道方向分辨率降至0.5公里。在705公里高度的EOS轨道上采用55度扫描模式，可形成2330公里的轨道条带宽度，每1至2天完成一次全球覆盖。单个MODIS一级B（Level 1B）250米数据粒（granule）包含由203次扫描构建的场景，每次扫描在跨轨方向采样5416次，对应约5分钟的数据量；因此每日可生成288个数据粒。由于单个MODIS扫描针对250米通道包含40个沿轨空间元素，该场景将由(5416 × 8120)个像元组成，空间覆盖范围为(2330公里 × 2040公里)。受MODIS扫描几何特性影响，当扫描角超过约17度时，扫描重叠度会逐渐升高。

该产品的短名称为MOD02QKM，采用地球观测系统分层数据格式（Earth Observing System Hierarchical Data Format, HDF-EOS）存储。单个文件的典型大小约为140 MB，每日总数据量约为22 GB。

基于MODIS L1B测量数据衍生的环境信息，可为全球范围内广泛多样的用户群体提供全面且前所未有的陆地、大气与海洋现象观测视角。

如需获取更多C6版产品信息，请访问MODIS表征支持团队网页：
https://mcst.gsfc.nasa.gov/l1b/product-information
或访问科学团队主页：
https://modis.gsfc.nasa.gov/data/dataprod/