Anticyclonic precession of a plume in a rotating environment
Published version
Peer-reviewed
Repository URI
Repository DOI
Change log
Authors
Abstract
jats:titleAbstract</jats:title>jats:pMotivated by potential effects of the Earth's rotation on the Deepwater Horizon oil plume, we conducted laboratory experiments on saltwater point plumes in a homogeneous rotating environment across a wide range of Rossby numbers 0.02≤jats:italicR</jats:italic>jats:italico</jats:italic>≤1.3. We report a striking physical instability in the plume dynamics near the source: after approximately one rotation period, the plume tilts laterally and starts to precess anticyclonically. The mean precession frequency <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/grl56325-math-0001.png" xlink:title="urn:x-wiley:grl:media:grl56325:grl56325-math-0001" /> scales linearly with the rotation rate Ω as <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/grl56325-math-0002.png" xlink:title="urn:x-wiley:grl:media:grl56325:grl56325-math-0002" />. We find no evidence of a critical Rossby number above which precession ceases. We infer that a conventionally defined Rossby number is not an appropriate parameter when the plume is maintained over a long time: provided Ω ≠ 0, rotation is always important to the dynamics. This indicates that precession may occur in persistent oceanic or atmospheric plumes even at low latitudes.</jats:p>
Description
Keywords
Journal Title
Conference Name
Journal ISSN
1944-8007