edu.ucar.opensky::articles:19600 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-26T02:37:07.590159 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7pg1th6 Relative contributions of momentum forcing and heating to high-latitude lower thermospheric winds 2017-01-01T00:00:00Z publication https://n2t.org/ark:/85065/d7pg1th6 https://doi.org/10.1002/2016JA023124 Kwak, Y. author Richmond, Arthur D. author UCAR/NCAR - Library publisher We discuss the significance of potential vorticity in the thermosphere and quantify the relative contributions of momentum forcing and heating to its total time derivative in the high-latitude lower thermosphere during the southern hemisphere summertime for negative interplanetary magnetic field (IMF) B-z conditions on the basis of numerical simulations. A term analysis of the potential vorticity equation for weak or strong southward IMF (B-z=-2.0nT or -10.0nT) gives the following results: the ratios of the momentum forcing term to the heating term at 142, 123, and 111km altitudes for IMF B-z=-2.0nT are roughly 6:1, 4:1, and 2:1, respectively, indicating that the momentum forcing term makes the larger contribution to the total time derivative of the potential vorticity, although the relative contribution of the momentum forcing weakens with descending altitude. The ratios of the momentum forcing term to the heating term at 142, 123, and 111km altitudes for IMF B-z=-10.0nT are roughly 3:1, 2:1, and 1:1, indicating that, at higher altitudes, the momentum forcing term makes the larger contribution to the total time derivative of the potential vorticity, but the relative contributions of momentum forcing and heating are comparable at lower altitudes. A comparison of the heating term and the momentum forcing term for IMF B-z=-2.0nT and IMF B-z=-10.0nT conditions indicates that the heating term increases more significantly than the momentum forcing term as IMF B-z becomes more negative. 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 2017 American Geophysical Union. None eng geoscientificInformation