Water Age Classification using LaTTE 2005

What is LaTTE?

LaTTE or Lagrangian Transport and Transformation Experiment was conducted to quantify mixing and the rate at which biological and chemical processes transform material in a buoyant coastal current.

It studies the processes that control the fate and transport of nutrients and chemical contaminants in the Hudson River plume.

What does my project do?

It attempts to:

Figure out how much of the Hudson River plume contributes to the high chlorophyll signal along the coast.

To arrive at a chlorophyll budget for the coastal waters along the LaTTE domain.

Set thresholds to classify river plume, old river water and shelf water.

Overlay ship salinity tracks on the image so generated to prove that the algorithm used is right.

What do I need?

What is my approach going to be?

Take channel ratios of nLw’s to define high CDOM water in the Hudson and Delaware waters.
Use the low values of nLw-490:nLw-670 to indicate fresh river water.
Values in between 3 and 4.5 indicate old river water (about 14 days old).
Overlay the salinity data over the ratio-ed and threshold-ed image.

How would I validate my algorithm?

Validation involves mapping salinity tracks from ship data.
At each boundary of changing chlorophyll values we see a corresponding change in salinity values.
This validates the algorithm used and proves conclusively that the technique used is correct.

Sample Results

What have I concluded from my project?

Band ratio-ing is a very effective technique for classifying blooms and older waters in the LaTTE region.
Plume material is transported offshore by hydrographic super highways.
It then onverges over the 25 m isobath and then dissipates possibly due to export flux and grazing.

References:

East Coast Plumes and Blooms: building a chlorophyll budget for the Mid- Atlantic Bight : Jennifer Bosch, Oscar Schofield, Scott Glenn, Josh Kohut
Dynamics and Optics of the Hudson River Outflow Plume : Donald R Johnson, Jerry Miller, Oscar Schofield
Methods of Satellite Oceanography, Stewart
Satellite Meteorology, Kidder and Vonder Haar
http://oceancolor.gsfc.nasa.gov/SeaWiFS/
http://oceancolor.gsfc.nasa.gov/
http://marine.rutgers.edu/cool/latte/

Special Thanks to:

Water Age Classification for LaTTE 2005