English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Determination of horizontal velocity fields on the solar surface is crucialfor understanding the dynamics of structures like mesogranulation orsupergranulation or simply the distribution of magnetic fields.  We pursue here the development of a method called CST for coherent structuretracking, which determines the horizontal motion of granules in the field ofview.  We first devise a generalization of Strous method for the segmentation ofimages and show that when segmentation follows the shape of granules moreclosely, granule tracking is less effective for large granules because ofincreased sensitivity to granule fragmentation. We then introduce themulti-resolution analysis on the velocity field, based on Daubechies wavelets,which provides a view of this field on different scales. An algorithm forcomputing the field derivatives, like the horizontal divergence and thevertical vorticity, is also devised. The effects from the lack of data or fromterrestrial atmospheric distortion of the images are also briefly discussed.

Tracking granules on the Sun's surface and reconstructing horizontal velocity fields: I. the CST algorithm