VIIRS/NPP Day/Night Band 6-Min L1B Swath 750m NRT

The VIIRS/NPP Day/Night Band 6-Min L1B Swath SDR 750m Near Real Time (NRT) product, short-name VNP02DNB_NRT is among the VIIRS Level 1 and Level 2 swath products that are generated from the processing of 6 minutes of VIIRS data acquired during the S-NPP satellite overpass. The Day/Night band (DNB) is a panchromatic channel covering the wavelengths from 500 nm to 900 nm, and sensitive to visible and near-infrared from daylight down to the low-level radiation observed at night.

The VIIRS DNB is much improved from previous products due in large part to its complicated continuous on-board calibration. In addition, new-moon Earth observations are used to estimate and remove stray light. These corrections are a first of its kind to provide on-orbit radiometric calibration. The corrections made to the DNB data are provided by the NASA VIIRS Characterization Support Team and are likely to continue to evolve given this new methodology.

The spatial resolution of the instrument at viewing nadir is approximately 750 m for the DNB and the Moderate-resolution Bands and and 375m for the Imagery bands. The DNB is aggregated to maintain nearly constant horizontal spatial resolution across the swath.

As the DNB is sensitive to nighttime radiation over the full lunar cycle, the incoming solar and lunar radiation must be properly modeled to calculate the reflectance. However, the DNB is sensitive to more sources of radiation than just the sun and moon.

VIIRS/NPP 日夜波段 6 分钟 L1B 波段 SDR 750 米近实时（NRT）产品，简称 VNP02DNB_NRT，属于由过境 S-NPP 卫星采集的 VIIRS 数据处理生成的 VIIRS 第一级和第二级波段产品之列。日夜波段（DNB）是一个涵盖 500 纳米至 900 纳米波长的全色通道，对从白昼至夜晚观测到的低强度辐射的可见光和近红外均具有敏感性。

VIIRS DNB 相较于以往产品有显著提升，这主要得益于其复杂的连续在轨校准。此外，利用新月地球观测数据来估算并去除杂散光。这些校正首次实现了在轨辐射校准。对 DNB 数据进行的校正由 NASA VIIRS 特征支持团队提供，并可能随着这一新方法的采用而不断演进。

该仪器在视场天顶的分辨率对于 DNB 和中分辨率波段约为 750 米，对于图像波段约为 375 米。DNB 通过聚合以保持整个波段的近恒定水平空间分辨率。

由于 DNB 对整个月球的夜间辐射敏感，因此必须正确模拟太阳和月球辐射来计算反射率。然而，DNB 对辐射的敏感性远不止太阳和月球。