Maximum angle method for determining mixed layer depth from seaglider data
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Authors
Fan, Chenwu
Chu, Peter C.
Subjects
Advisors
Date of Issue
2011
Date
2011
Publisher
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Abstract
A new maximum angle method has been developed to determine surface mixed-layer (a 19 general name
for isothermal/constant-density layer) depth from profile data. It has three steps 20 (1) fitting the profile
data with a first vector (pointing downward) from a depth to an upper level 21 and a second vector
(pointing downward) from that depth to a deeper level, (2) identifying the 22 angle (varying with depth)
between the two vectors, (3) finding the depth (i.e., the mixed layer 23 depth) with maximum angle between
the two vectors. Temperature and potential density profiles 24 collected from two seagliders in the Gulf
Stream near Florida coast during 14 November ? 5 25 December 2007 were used to demonstrate its
capability. The quality index (1.0 for perfect 26 identification) of the maximum angle method is about 0.96.
The isothermal layer depth is 27 generally larger than the constant-density layer depth, i.e., the barrier
layer occurs during the 28 study period. Comparison with the existing difference, gradient, and curvature
criteria shows the 29 advantage of using the maximum angle method. Uncertainty due to varying threshold
using the 30 difference method is also presented.
Type
Article
Description
Journal of Oceanography, Oceanographic Society of Japan, 67
Series/Report No
Department
Oceanography
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Citation
Chu, P.C., and C.W. Fan, 2011: Maximum angle method for determining mixed layer depth from seaglider data. Journal of Oceanography, Oceanographic Society of Japan, 67, 219-230 (paper download).
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This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.