VJ202DNB - VIIRS/JPSS2 Day/Night Band Moderate Resolution 6-Min L1B Swath 750m

VJ202DNB is the short-name of the Joint Polar Satellite System-2 (JPSS-2/NOAA-21; referred to hereafter as J2) platform-derived single NASA VIIRS panchromatic Day-Night band (DNB) calibrated radiance product. The DNB is one of the M-bands with an at-nadir spatial resolution of 750 meters (across the entire scan). The panchromatic DNB’s spectral wavelength ranges from 0.5 µm to 0.9 µm. It facilitates measuring night lights, reflected solar/lunar lights with a large dynamic range between a low of a quarter moon illumination to the brightest daylight. The DNB attempts to maintain a nearly constant 750-m resolution over the entire 3060 km orbital swath by resorting to an on-board aggregation method, which also renders the calibration of the DNB a challenge. Stray-light and other sources of noise (lunar illuminance, twilight, clouds, noisy scan-edges, etc.) affect the DNB quality, and warrant correction. Considered a major advance in low-light imaging, the VIIRS DNB owes its heritage to the Operational Linescan System (OLS) visible sensors that were part of the Defense Meteorological Satellite Program (DMSP) platforms since the 1970s. The image dimensions of the 750-m DNB product measure 3232 lines by 4064 pixels. The data product described in this landing page is a v2.1 collection and its data record starts from February 10, 2023.

Radiometric Calibration-specific changes
The following updates define the changes implemented in the v2.1 collections:

1. Applied the Total and Spectral Solar Irradiance Sensor-1 (TSIS-1) solar spectral irradiance.
2. Improved screen functions derived from yaw maneuvers combined with regular on-orbit solar diffuser calibration data.
3. Addressed the time-dependent striping mitigation for Visible Near Infrared bands M1-M3.
4. Updated the Delta-C look-up table (LUT) to correct the M4 low-gain error in the pre-launch LUT.
5. The recently available Day-Night Band (DNB) Mid-Gain State (MGS) Relative Spectral Response (RSR) is applied to High-Gain State (HGS) and MGS calibration, which previously only used the Low-Gain State (LGS) RSR in the earlier version v3.2.3.x.

Radiometric accuracy
Radiometric accuracy forms a key requirement that enables us to derive good quality L2 retrievals and provide the basis for higher-level products. In the case of the v2.1 J2 VIIRS L1 product, the DNB’s defined radiometric calibration uncertainty for the effective in-band radiance over a uniform scene is gain-state dependent.