MODIS/Terra Calibrated Radiances 5-Min L1B Swath 1km

The MODIS/Terra Calibrated Radiances 5Min L1B Swath 1km data set contains calibrated and geolocated at-aperture radiances for 36 discrete bands located in the 0.4 to 14.4 micron region of the electromagnetic spectrum. These data are generated from the MODIS Level 1A scans of raw radiance which during processing are converted to geophysical units of W/(m^2 um sr). Additional data are provided including quality flags, error estimates and calibration data.

Visible, shortwave infrared, and near infrared measurements are only made during the daytime (except band 26), while radiances for the thermal infrared region (bands 20-25, 27-36) are measured continuously.

The shortname for this product is MOD021KM and is stored in the Earth Observing System Hierarchical Data Format (HDF-EOS). A typical file size is approximately 110 MB (a day granule around 150MB and a night granule around 70 MB).

In this new version (Collection 6.1) of MOD021KM, an advanced technique is introduced to mitigate the crosstalk contamination issue among the LWIR PV bands
using data from lunar calibration events.

The electronic crosstalk contamination issue in the Terra long-wave infrared photovoltaic (LWIR PV) bands (27 -30), has existed since the beginning of the mission but become more noticeable during later half of the mission. The electronic crosstalk is where signal from each of the detectors among the LWIR PV bands can leak to the other detectors, producing a false signal contribution. This contamination has had a noticeable effect on the MODIS science products since 2010 for band 27, and since 2012 for bands 28 and 29.

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 定标辐射率5分钟L1B条带1km数据集（MODIS/Terra Calibrated Radiances 5Min L1B Swath 1km）包含覆盖电磁波谱0.4至14.4微米区间的36个离散波段的经定标与地理定位的孔径内辐射率。此类数据源自MODIS一级A（Level 1A）原始辐射率扫描数据，经处理后转换为物理单位W/(m²·μm·sr)。此外还附带质量标志、误差估计值与定标数据等附加信息。

可见光、短波红外与近红外波段仅在日间进行测量（26波段除外），而热红外区域（波段20-25、27-36）的辐射率则可连续获取。

该产品的短名称为MOD021KM，以地球观测系统分层数据格式（Earth Observing System Hierarchical Data Format，HDF-EOS）存储。典型文件大小约为110MB（单日数据块约150MB，夜间数据块约70MB）。

在MOD021KM的此次更新版本（第六版修订版1，Collection 6.1）中，引入了一项先进技术，利用月球定标事件的数据缓解长波红外光伏（LWIR PV）波段间的串扰污染问题。

Terra卫星长波红外光伏（LWIR PV）波段（27-30）的电子串扰污染问题自任务启动以来便已存在，但在任务后期愈发显著。电子串扰指长波红外光伏波段中各探测器的信号会相互泄露，从而产生虚假信号贡献。自2010年起，该污染对27波段的MODIS科学产品产生显著影响；2012年起则波及28与29波段。

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关于陆地、大气与海洋现象的全面且前所未有的观测视角。

如需了解更多第六版产品信息，请访问MODIS定标支持团队网页：
https://mcst.gsfc.nasa.gov/l1b/product-information
或访问科学团队主页：
https://modis.gsfc.nasa.gov/data/dataprod/