NPP/VIIRS Moderate-Resolution Dual Gain Bands Calibrated Radiance 6 Min L1B Swath 750m NRT

The NPP/VIIRS Moderate-Resolution Dual Gain Bands Calibrated Radiance 6-Min L1B Swath 750m Near Real Time (NRT) product, short-name VNP02GDC, contains unaggregated, calibrated TOA radiances for those VIIRS sub-pixel samples that are aggregated along-scan during post-calibration ground processing. In other words, this file contains the calibrated M1- M5, M7 and M13 dual gain band data from the nadir and near-nadir zones that would otherwise be discarded following post-calibration aggregation/Earth View Radiometric Calibration Unit.

The VIIRS Level-1 and Level-2 swath products are generated from the processing of 6 minutes of VIIRS data acquired during the NPP satellite overpass. The VIIRS sensor has 5 high-resolution imagery channels (I-bands) that have 32 detectors (32 rows of pixels per scan), with twice the resolution of the M-bands and the DNB, that span the wavelengths from 0.640 micron to 11.45 micron. There are also 7 dual-gain VIIRS bands. The dual gain moderate resolution bands (M1 to M5, M7 and M13) have 6304 samples and the other moderate resolution bands have 3200.

For additional information, see the Algorithm Theoretical Basis Document (ATBD) for the L1B product (https://ladsweb.modaps.eosdis.nasa.gov/missions-and-measurements/viirs/…). The document describes how VIIRS operates in space and provides the equations implemented by the L1B software to generate the MODIS Level-1 intermediate products. It is a summary document the presents the formulae and error budges used to transform VIIRS digital counts to radiance and reflectance.

NPP/VIIRS 中分辨率双增益波段校准辐射率 6 分钟 L1B 带状数据产品，简称 VNP02GDC，包含在地面后校准处理过程中沿扫描方向进行聚合的 VIIRS 子像素样本的未经聚合的校准 Top-of-Atmosphere (TOA) 辐射率。换言之，该文件包含了来自正下方和近正下方区域的校准 M1-M5、M7 和 M13 双增益波段数据，这些数据在经过后校准聚合/地球视角辐射校准单元处理后本应被废弃。

VIIRS 的 Level-1 和 Level-2 带状产品是通过处理 NPP 卫星过境期间获得的 6 分钟 VIIRS 数据生成的。VIIRS 传感器具有 5 个高分辨率成像通道（I 波段），每个通道包含 32 个探测器（每扫描线 32 行像素），其分辨率是 M 波段和 DNB 的两倍，波长范围从 0.640 微米到 11.45 微米。此外，还有 7 个双增益波段。双增益中分辨率波段（M1 至 M5、M7 和 M13）包含 6304 个样本，而其他中分辨率波段包含 3200 个样本。

有关更多信息，请参阅 L1B 产品算法理论基础文档 (Algorithm Theoretical Basis Document, ATBD)（https://ladsweb.modaps.eosdis.nasa.gov/missions-and-measurements/viirs/…）。该文档描述了 VIIRS 在太空中的工作原理，并提供了 L1B 软件实现的将 VIIRS 数字计数转换为辐射率和反射率的方程式。这是一份总结性文档，展示了用于将 VIIRS 数字计数转换为辐射率和反射率的公式及误差预算。