edu.ucar.opensky::articles:25197 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-25T15:21:33.614979 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7cr5xzr HL-TWiM empirical model of high-latitude upper thermospheric winds 2019-12-01T00:00:00Z publication https://n2t.org/ark:/85065/d7cr5xzr https://doi.org/10.1029/2019JA027188 Dhadly, M. S. author Emmert, J. T. author Drob, D. P. author Conde, M. G. author Aruliah, A. author Doornbos, E. author Shepherd, G. G. author Wu, Qian author Makela, J. J. author Niciejewski, R. J. author Lee, C. author Jee, G. author Ridley, A. J. author UCAR/NCAR - Library publisher We present an empirical model of thermospheric winds (High-latitude Thermospheric Wind Model [HL-TWiM]) that specifies F region high-latitude horizontal neutral winds as a function of day of year, latitude, longitude, local time, and geomagnetic activity. HL-TWiM represents the large-scale neutral wind circulation, in geomagnetic coordinates, for the given input conditions. The model synthesizes the most extensive collection to date of historical high-latitude wind measurements; it is based on statistical analyses of several decades of F region thermospheric wind measurements from 21 ground-based stations (Fabry-Perot Interferometers and Scanning Doppler Imaging Fabry-Perot Interferometers) located at various northern and southern high latitudes and two space-based instruments (UARS WINDII and GOCE). The geomagnetic latitude and local time dependences in HL-TWiM are represented using vector spherical harmonics, day of year and longitude variations are represented using simple harmonic functions, and the geomagnetic activity dependence is represented using quadratic B splines. In this paper, we describe the HL-TWiM formulation and fitting procedures, and we verify the model against the neutral wind databases used in its formulation. HL-TWiM provides a necessary benchmark for validating new wind observations and tuning our physical understanding of complex wind behaviors. Results show stronger Universal Time variation in winds at southern than northern high latitudes. Model-data intra-annual comparisons in this study show semiannual oscillation-like behavior of GOCE winds, rarely observed before in wind data. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright 2019 American Geophysical Union. None eng geoscientificInformation