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NASA Calibration Plots

Monthly NPOL Calibration Plots 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Calibration of NPOL is critical for validation of the GPM satellite. By monitoring the radar reflectivity bias found in Zh and Zdr products, the GPM team is able to adjust accordingly and provide an accurate means of ground validation of GPM instrument sensors.

Various methods are used to determine the current state of the bias including self-consistency checks (Ryzhkov et al., 2005), relative calibration adjustments (Wolff et al. 2015), and birdbath scan analysis (Gorgucci et al., 1999). The historical and real-time plots available here allow an individual to track the progression of NPOL bias throughout the course of the mission.

NPOL Site Instrument Comparisons

Latest NPOL & MRRpro Reflectivities Every ~12 minutes NPOL conducts a birdbath scan (BB) in which the antenna scans at 90° elevation through 2 revolutions. The following plot is a comparison between NPOL & MRRpro scans during BB scan times.

Latest NPOL vs. MRRpro The NPOL range gate at 744m & reflectivity values between 20 - 30 dBZ were selected to account for side lobe interference of NPOL near the surface, and attenuation experienced by the MRRpro respectively. 735m is the closest MRRpro range gate to 744m.	Latest Parsivel vs. MRRpro For ground validation purposes the Parsivel is compared alongside the MRRpro at 70m. The 70m range gate is to account for interference experienced in gates closest to the surface.