The Significant Roles of COSMIC2 GNSS RO in NOAA Integrated Calibration/Validation System for NWP
Presenter:
Changyong Cao
NOAA
(1)NOAA; (2)NOAA affiliates
Talk
GNSS radio occultation (RO) has been recognized as a key observable for Numerical Weather Prediction (NWP) and climate change detection. Based on decades of studies with research missions such as COSMIC, GNSS RO has matured to become an important, sustained component of NOAA satellite observations and contributor to NWP, complementing microwave and infrared sounding measurements. The successful launch of FORMOSAT-7/COSMIC-2 denotes a major milestone achieved for transitioning GNSS RO to a routine core NOAA satellite observation with operational 24/7 support for weather forecasting. With state-of-the art technology and advanced capabilities, the TriG GNSS receiver on COSMIC-2 is expected to significantly outperform previous instruments, which is likely to make the measurements a new reference standard for GNSS RO in the next decade. Given the proliferation of GNSS RO missions including the emerging GNSS RO sensors on constellations of current and future satellites from many countries, as well as the heterogeneity of data provided by vendors under the Commercial Weather Data Pilot (CWDP) project in the US, it is imperative to ensure the consistency, accuracy, precision of the measurements with well understood uncertainties.
Recognizing the significance of GNSS RO and the emerging challenges, the NOAA Center for Satellite Applications and Research (STAR) has extended the well-established Integrated Calibration/Validation System (ICVS) to incorporate GNSS RO as a major component of the system, preparing to use COSMIC-2 as a reference for all GNSS RO measurements and atmospheric soundings. The ICVS monitors NOAA satellite measurements from all operational satellite radiometers in both polar-orbiting and geostationary orbits including the Joint Polar Satellite System (JPSS), Geostationary Operational Environmental Satellite (GOES-R) series, and MetOp by EUMETSAT, with thousands of parameters updated daily. This paper introduces the ICVS system in relation to GNSS RO and its extension to support GNSS RO missions including COSMIC-2, KOMPSAT-5, PAZ, CWDP and other missions. The functionality of the system using COSMIC-2, KOMPSAT-5, and PAZ data is exemplified. The significant roles of GNSS RO in bias monitoring relative to microwave and infrared hyperspectral sounders such as ATMS, CrIS, and radiosonde measurements, as well as monitoring of GNSS RO instrument performance and anomaly investigation are discussed. The goal is to enhance the ICVS to incorporate GNSS RO to monitor, improve, and harmonize the quality of satellite observations from operational weather and environmental satellites, ensuring consistent accuracy among space-based observations for weather forecasting, climate monitoring, and environmental applications, in support of the WMO Global Space-based Inter-Calibration System (GSICS) initiatives.
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