Analysis of Riverine Skin Temperature Response to Surface and Subsurface Processes
Abstract
Analysis of Riverine Skin Temperature Response to Surface and Subsurface Processes Christopher J. Zappa Lamont-Doherty Earth Observatory Columbia University Ocean and Climate Physics Division 61 Route 9W, Palisades, NY 10964 Phone: 845-365-8547; zappa@ldeo.columbia.edu PROJECT SUMMARY The over-arching goal of this proposed study is to use infrared imaging of water surface patterns to deliver remote measurements of flow rate and turbulence intensity, and information on surface- and subsurface-generated turbulent structures in rivers. A prototype field campaign was performed in the Hudson River in November 2010 that included the high sensitivity, high resolution, longwave infrared measurements of SST. The subsurface mean and turbulent velocity was monitored using a frame of acoustic Doppler velocimeters, three pulse-coherent sonars (1- cm resolution), and three temperature and conductivity sensors to profile the river with depth. An important component of this study is the direct measurement of heat, mass and momentum fluxes across the air-water interface, as well as the radiative forcing. At the core of this proposal is the continued analysis for three publications from our collaboration with Areté Associates on our Hudson River data sets from November 2010. 1) Prediction of water depth from surface integral length scales of turbulence derived from autocorrelation functions of skin temperature from infrared imagery. (What do the scales of boils tell us!) We will relate the scales of turbulence quantified from IR imagery of the river s water surface directly to the subsurface scales of turbulence in order to determine remotely the flow rate, subsurface turbulence, and bed stress. 2) Variability and modeling of skin temperature as a function of environmental forcing in riverine and estuarine systems. (When are boils observed and not!) We will determine the dependence of SST variability and coherent structures on the net heat flux and freesurface turbulence from environmental forcing including wind and tides using IR imagery. We will also determine the limits of using SST variability to remotely measure the flow rate, subsurface turbulence, and bed stress. 3) Observations of wind gustiness in infrared imagery. (Changes in surface roughness can disrupt the surface thermal boundary layer. Changes in surface roughness can also change the emissivity at high incidence angles. Gustiness can also increase the local heat flux and the change the temperature gradient across surface thermal boundary layer. All impact the IR signature due to gustiness.) The study will reveal the effects of wind gustiness on the SST variability and on the ability to remotely measure the flow rate, subsurface turbulence, and bed stress.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2016
- Source ID
- N000141512153
Entities
People
- Christopher J Zappa
Organizations
- Office of Naval Research
- Trustees of Columbia University in the City of New York
- United States Navy