Document Type

Post-Print

Publication Date

2011

Subjects

Snohomish River (Wash.) -- Streamflow -- Measurement, Snohomish River (Wash.) -- Turbulence, Snohomish River (Wash.) -- Remote sensing

Abstract

Thermal infrared (IR) based particle image velocimetry (PIV) is used to measure the evolution of velocity, turbulent kinetic energy (TKE), and the TKE dissipation rate at the water surface in the tidally influenced Snohomish River. Patterns of temperature variability in the IR imagery arise from disruption of the cool skin layer and are used to estimate the 2D velocity field. Comparisons of IR based PIV mean velocity made against a collocated acoustic velocimeter demonstrate high correlation (r2 > 0.9). Over a tidal period, surface TKE computed from the IR velocity varies from 10-4 J·kg-1 to 3x10-3 J·kg-1, with an average difference from the in situ measurements of 8%. IR-derived TKE dissipation rates vary from approximately 3x10-6 W·kg-1 to 2x10-4 W·kg-1 at peak ebb, agreeing on average to within 7% of the in situ velocimeter results. Infrared-based PIV provides detailed measurements of previously inaccessible surface flow and turbulence statistics.

Description

This is an Author's Original Manuscript of an article whose final and definitive form, the Version of Record, has been published in Geoscience and Remote Sensing Letters, IEEE (Vol 8, Issue 5) 2011. The article is available online at: http://dx.doi.org/10.1109/LGRS.2011.2125942

DOI

10.1109/LGRS.2011.2125942

Persistent Identifier

http://archives.pdx.edu/ds/psu/11189

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