Remotely Sensed Reflectance over the Heuksan Mud Belt, Korea

Catherine Evans

Supervisor: Dr. Paul Hill

AGS Colloquium 2019

Introduction to the Project

• Remote sensing can give surfacepatterns of ocean color.

• Sediment changes the ocean color.

• Can we infer subsurfacesedimentary processes with satellite images?

Image Source: Chardon (2008)

Suspended Particulate Matter Matters?• Visibility hazards

• Navigation

• Affects productivity

• Transports pollutants

How do we study Suspended Sediment?

• In Situ Measurements• Landsat 8 - Bands 4 and 5

Primary Study Site • Heuksan Mud Belt (HMB)

• Southeastern Yellow Sea.

• Mud and silt.

• Macrotidal environment.

• Peak flow speed of 1.5 m/s.

Lee, Yong (2001)

Field Results

• Stratified at peak flow

• Very high concentration

Sediment Concentration Vs. Depth

Project Goals• Determine reflectance patterns over channel

and ridge.

• Explore reasons for variability.

• Link to subsurface mechanisms.

Hypothesis

• Banded pattern matches bathymetry.

• Tidal current creates lutocline.

• Remote sensing can determine subsurface process with surface SPM.

Methods

Environmental Variables

Ridge and Channel Reflectance

Statistical Tests and

Interpretations

Results

Landsat Bands 4 and 5 (B4, B5)

Image source: https://earthexplorer.usgs.gov/

Heuksan Mud Belt (HMB)

Channel Reflectance Levels: Bathymetry• Bathymetry vs reflectance

demonstrates a negative trend.

• Due to tidal current, lutocline.

• Subsurface processes resolved from space.

Why do we see these patterns?

• Channel has a lower reflectance than ridge.

• What causes variability?• Environmental variables

Correlation Results: HMB

Sites

https://commons.wikimedia.org/wiki/Maps_of_the_world#/media/File:BlankMap-World-v2.png

Heuksan Mud Belt (HMB) Gyeonggi Bay (GB) Gulf of Khambhat (GOK)1 2 3

N = 15 N = 46N = 15

Gyeonggi Bay (GB)

Gulf of Khambhat (GOK)

Channel Reflectance Levels: Bathymetry

Conclusions

• Surface reflectance correlates with depth in all three sites.

• Supports hypothesis of suspended sediment stratification at depth.

• Subsurface process resolved with remote sensing of surface.

• Method for identifying other areas for suspended sediment stratification in tidal seas.

Acknowledgements

• Dr. Paul Hill

• Dalhousie University Faculties of Earth Sciences & Oceanography

• Department of The Navy Office of Naval Research

• Fisheries and Oceans Canada

• Coordinators and hosts of AGS

Sources

• Hill, P. (TBA).• Lee, H. J. (2001). Origin of Inner-Shelf Mud Deposit in the Southeastern

Yellow Sea: Huksan Mud Belt. Journal of Sedimentary Research, 144-154.• Lee, H. J. (2015). A Review on the Holocene evolution of an Inner-shelf

Mud Deposit in the Southeastern Yellow Sea: the Huksan Mud Belt. Ocean Science Journal, 615-621.

• Park S. C., L. H. (2000). Evolution of late Quaternary mud deposits and recent sediment budget in the southeastern Yellow Sea. Marine geology, 271-288.

• WorldMap. https://commons.wikimedia.org/wiki/Maps_of_the_world#/media/File:BlankMap-World-v2.png