Abstract

NOAA Space Weather Prediction Center is the official provider of US space weather alerts, watches, and warnings. With the rise in GNSS users and the revitalized needs of the International Civil Aviation Organization (ICAO), SWPC is now required to provide total electron content across the globe (Glo-TEC), and regional estimates of ionospheric scintillation. GloTEC is a global-scale three-dimensional electron density data assimilation scheme used to optimally estimate three-dimensional ionospheric electron density. It uses ground and space-based (e.g., COSMIC-II and commercial providers) data to produce a tomographic reconstruction of the ionosphere using a Gauss-Markov Kalman Filter and uses International Reference Ionosphere 2016 (IRI-16) as the background model. An anomaly product is also provided. It reveals large scale trends in the vertical Total Electron Content (vTEC) by comparing the current output to the average vTEC over the prior 10 days. The anomaly map is used to identify abnormal ionospheric conditions, like large TEC enhancements or depletions that can be evidence of the presence of features that can adversely affect GNSS radio frequency signal propagation. Maps of Rate of TEC Index (ROTI) are also generated calculated by the standard deviation of the detrended rate of change of slant TEC as observed by a ground-based GNSS receiver. High ROTI values indicate the presence of ionospheric plasma irregularities like strong gradients and plasma bubbles that cause intense phase fluctuations (????????) and amplitude scintillation (S4). Efforts are underway to improve these GNSS targeted products, which includes applying Carrano et al. (2019) method to convert the ROTI estimates to S4 and ???????? and combining the space-based geolocated estimates of S4 from COSMIC-II with the ground-based estimates from ROTI. In this presentation, we will demonstrate how these new developments are improving our products and strengthening our capability to provide regional nowcast for ionospheric scintillation.