Submarine groundwater discharge revealed by aerial thermal infrared imagery: a case study on Jeju Island, Korea

Abstract

Submarine groundwater discharge (SGD) is a global phenomenon that carries large volumes of groundwater and dissolved chemical species such as nutrient, metals, and organic compounds to coastal zones. We report the influence of SGD on the coastal waters of Jeju Island, Korea, using high‐resolution aerial thermal infrared (TIR) mapping techniques and field investigations. An aircraft‐based system was implemented using a cost‐effective TIR camera for aerial TIR mapping. Ground‐based calibrations and system integration with GPS/IMU (global positioning system/inertial measurement unit) were performed for the aerial systems. The aerial surveys showed distinct low‐temperature signatures of SGD along the coasts of Jeju Island, revealing large groundwater inputs from the coastal aquifers to the ocean. Multiple aerial surveys over a range of seasons and tidal stages revealed that SGD rates dynamically affect the sea surface temperature (SST) of the coastal zone. The in‐situ measurements supported that SGD has a substantial influence on the coastal water chemistry as well as SST. Our observations highlight the extent to which aerial‐based TIR mapping can serve as a powerful tool for studying SGD and other coastal processes. Copyright © 2016 John Wiley & Sons, Ltd.

Integration of aerial infrared thermography and in situ radon‐222 to investigate submarine groundwater discharge to Pearl Harbor, Hawaii, USA

“…The SST maps also illustrate that, ideally, radon models for time‐series stations should incorporate a new area and volume estimate for each analysis cycle because the plumes are dynamic. Although challenging, one could conceivably determine areas and volumes for each analysis cycle by using distributed temperature sensors or through continuous TIR data collection by a perched camera from a high vantage point, manned flights, or drones (e.g., Lee et al ; Kennedy ). Our TIR data also generally had a much higher resolution (3.2 m) than our radon survey data (1 to 100 m).…”

Quantitative estimation of submarine groundwater discharge using airborne thermal infrared data acquired at two different tidal heights

“…The reason that the amount of SGD in Bangdu Bay is greater than in other typical continental margins is the inclusion of recirculated SGD across the sediment–seawater interface. The SGD in Gongcheonpo Beach is known to mainly consist of SFGD (E. Lee, Kang, et al, ). Lastly, Kimnyung Bay is made of a harbour that is relatively deeper than other typical beach or bay.…”

“…Airborne TIR remote sensing has been used in an attempt to show the spatial variability of SGD at higher spatial resolutions than space‐borne TIR imagery is capable of demonstrating (Bejannin, van Beek, Stieglitz, Souhaut, & Tamborski, ; Kelly, Glenn, & Lucey, ; Mejías et al, ; Mulligan & Charette, ; Tamborski et al, ). Our research team has previously presented the possibility of detecting SGD around Jeju Island using airborne TIR imagery (E. Lee, Kang, et al, ).…”

Investigation of submarine groundwater discharge to tidal rivers: Evidence for regional and local scale seepage

“…Previous studies have utilized a variety of remote sensing platforms to investigate groundwater discharge patterns and rates under different hydrogeologic regimes, including point‐source (Kelly et al ., ) and diffuse SGD (Lee et al ., ) in a volcanic environment (Hawaii and Jeju Island, Korea, respectively), diffuse SGD from a permeable unconfined coastal aquifer (Long Island Sound, NY; Tamborski et al ., ), and from freshwater springs (Prince Edward Island, Canada; Danielescu et al ., ). To utilize TIR remote sensing techniques for hydrologic investigations, it is necessary that a wide variety of hydrologic environments under a range of environmental conditions be thoroughly studied.…”

“…Lee et al . () found that coastal sea‐surface temperatures (measured by airborne TIR remote sensing) changed with temporally variable fresh SGD rates, in response to a tidally modulated hydraulic gradient. Ground‐based TIR imagery can be used to detect small‐scale groundwater discharge springs that are not readily apparent to the naked eye, even in porous systems where groundwater seepage is expected to be primarily diffuse (Röper, Greskowiak, & Massmann, ).…”