Secchi disk depth: A new theory and mechanistic model for underwater visibility
By Z. Lee, S. Shang, Chuanmin Hu, Keping Du, A. Weidemann, W. Hou, Junfang Lin, G. Lin. 2015
305 citations recorded by the source corpus.
Abstract Secchi disk depth ( Z SD ) is a measure of water transparency, whose interpretation has wide applications from diver visibility to studies of climate change. This transparency has been explained in the past 60 + years with the underwater visibility theory, the branch of the general visibility theory for visual ranging in water. However, through a thorough review of the physical processes involved in visual ranging in water, we show that this theory may not exactly represent the sighting of a Secchi disk by a human eye. Further, we update the Law of Contrast Reduction, a key concept in visibility theory, and develop a new theoretical model to interpret Z SD . Unlike the classical model that relies strongly on the beam attenuation coefficient, the new model relies only on the diffuse attenuation coefficient at a wavelength corresponding to the maximum transparency for such interpretations. This model is subsequently validated using a large (N = 338) dataset of independent measurements covering oceanic, coastal, and lake waters, with results showing excellent agreement (~ 18% average absolute difference, R 2 = 0.96) between measured and theoretically predicted Z SD ranging from 30 m without regional tuning of any model parameters. This study provides a more generalized view of visual ranging, and the mechanistic model is expected to significantly improve the current capacity in monitoring water transparency of the global aquatic environments via satellite remote sensing.
Subfields: Ecology, Oceanography
View Paper: https://www.semanticscholar.org/paper/c538c9afb705fdf1971866aa8bc2da488612bb96
How researchers see this paper
The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.
In Ecology
- John D. Hedley
- Peter J. Mumby
- Alastair R. Harborne
- William J. Skirving
- Assefa M. Melesse
- Scarla J. Weeks
- Iliana Chollett
- Sonia Bejarano
In Oceanography
- John D. Hedley
- William J. Skirving
- Peter J. Mumby
- Assefa M. Melesse
- Mohammad Haji Gholizadeh
- Scarla J. Weeks
- Lakshmi Reddi
- D. Burkepile
Citations in the corpus
- A Comprehensive Review on Water Quality Parameters Estimation Using Remote Sensing Techniques (2016, background): “[178] introduced a model to estimate the SDD, which unlike the classical model that relies strongly on the beam attenuation coefficient, the new model relies only on the diffuse attenuation coefficient at a wavelength corresponding to the maximum transparency for such interpretations.”
- A Revised Underwater Image Formation Model (2018, background): “Generally, is 2-5 times greater than Kd [23], and both contribute to the effective attenuation captured in a photograph, as we discuss in the next section.”
- Remote Sensing of Coral Reefs for Monitoring and Management: A Review (2016, background): “Whilst not a direct measurement of transparency and somewhat imprecise (Secchi depth can vary as much as 20% due to solar angle) Secchi depth benefits from a long historical record and millions of measurements worldwide, and recent work has improved the theoretical basis and alignment of Secchi dept”