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John Dellomo

Publications and source records attributed to John Dellomo.

4 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2020

SEASONAL VARIATION IN THE MEASUREMENT OF GOES-16 ABI CHANNEL-TO-CHANNEL REGISTRATION

An Image Navigation and Registration (INR) Performance Assessment Tool Set (IPATS) was developed to assess the US Geostationary Operational Environmental Satellite R-series (GOES-R) Advanced Baseline Imager (ABI) and Geostationary Lighting Mapper (GLM) INR performance.Channel-to-channel registration (CCR) is one of the five INR performance metricsproduced by IPATS. A seasonal variationis observed in the CCR assessment in north-south direction when one or both channels are reflective. However, indirect CCR, calculated as the difference of NAV measurements between two channels, does not presentthe similar seasonal variation. The phenomenon of the seasonal variationcoincides with the annual change of the subsolar point location. The amplitude of the seasonal variation is related tothe length and the direction of the shadow. DirectCCR, measured by IPATSdirectly,performs better than indirect CCR when both channels are visible wavelengthsor emissivechannels. For all other channel paircombinations, the assessment of indirect CCR is more accurate.

Bin Tan↗
NASA NTRS2020

SNPP and NOAA-20 VIIRS On-Orbit Geolocation Trending and Improvements

Two Visible Infrared Imaging Radiometer Suite (VIIRS) sensors have been in operations for more than 8.5 and 2.5 years since they were launched in October 2011 on SNPP satellite and in November 2017 on NOAA-20 satellite, respectively. These are two satellites in the Join Polar Satellite System (JPSS) constellation, of which Suomi National Polar-orbiting Partnership (SNPP) is a risk reduction satellite and NOAA-20 is the first of four JPSS satellites(JPSS-1 became NOAA-20 after launch). Accurate geolocation is a critical element in data calibration for accurate retrieval of global biogeophysical parameters. In this paper, we describe the latest trends in the continuously improved geolocation accuracy in VIIRS Collection-1 (C1) and C2 re-processing. We implemented a VIIRS instrument geometric model update (VIGMU)for both sensors that correct for geolocation error oscilations in the scan direction. We borrowed code from Moderate Resolution Imaging Spectroradiometer (MODIS) geolocation software to correct for time-dependent pointing variations, that are particularly acute in NOAA-20 VIIRS, and some pointing anomalies in SNPP VIIRS. We developed a Kalman Filter using gyrodata to correct for attitude errors due to the degradation of the star trackers performance from the SNPP satellite. We also present an improved ground control point matching (CPM) tool, in which the ground control point (GCP) chips library is refreshed using recently launched Landsat-8 images.

SNPP↗
NASA NTRSDate not supplied

Terra Orbit Drift and its Impacts on MODIS Geometric Performance

NASA Terra satellite has provided earth observations from its 5 onboard instruments for 25 years since its launch in December 1999. All these instruments are still mostly healthy, and observations are expected to extend 2 more years of life into late 2026. The onboard fuel is preserved by ceasing inclination adjust maneuvers (IAMs, stopped 2020) and drag make-up maneuvers (DMUs, stopped 2022). Without IAMs, the orbital plane is drifting, changing the sunlight conditions by late 2026 from nominal 10:30 AM to 8:30 AM local time at descending node (LTDN). The ceasing of DMUs combined with a constellation exit maneuver in October 2022 result in orbit altitude drifting down. Altitude will drift from a nominal mean of 715 km to 702 km by late 2026. A companion earth observing satellite, Aqua, is going through a similar orbit drift process. This presentation shows the details of the drifts, that have potentials to impact data products, especially those products from the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on Terra and Aqua satellites.

Guoqing (Gary) Lin↗