edu.ucar.opensky::articles:7165 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-26T15:39:07.432921 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7mp53kc Sun-as-a-star observations: Evidence for degree dependence of changes in damping of low- ℓ p modes along the solar cycle 2007-03-01T00:00:00Z publication https://n2t.org/ark:/85065/d7mp53kc https://doi.org/10.1051/0004-6361:20066419 Salabert, David R. author Chaplin, W. author Elsworth, Y. author New, R. author Verner, G. author UCAR/NCAR - Library publisher Aims.We use 9.5-yr of BiSON Sun-as-a-star data to search for dependence of solar-cycle parameter changes on the angular degree, ℓ of the data. The nature of the Sun-as-a-star observations is such that for changes measured at fixed frequency, or for changes averaged across the same range in frequency, any ℓ dependence present carries information on the latitudinal distribution of the agent (i.e., the activity) responsible for those changes. Methods.We split the 9.5-yr timeseries into contiguous 108-d pieces, and determine mean changes in the damping of, power in, and energy supplied to the modes through the solar cycle. We also apply a careful correction to account for the deleterious effects of the ground-based BiSON window function on the results. Results.From our full analysis we obtain a marginally significant result for the damping parameter, where the mean change is found to be weakest at ℓ=0. The other parameters show hints of some dependence in ℓ. Conclusions. Our main conclusion is that the mean fractional solar-cycle change in the ℓ=0 damping rates is approximately 50% smaller than was previously assumed. It had been common practice to use an average over all low-ℓ modes; our downward revision of the radial-mode value has implications for comparisons with models of the global solar cycle changes, which are usually based on a spherically symmetric geometry. 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 2007 European Southern Observatory. None eng geoscientificInformation