Research Statement

 

Sung-ho Hong, Ph.D.

 

My current research focuses on hydrology remote sensing and GIS, specifically on estimation of the spatio-temporal distribution of energy balance components and soil moisture from various satellite images. I am deeply interested in fundamental questions of how all the energy balance components and soil moisture can be accurately estimated from satellite imagery at different spatial and temporal scales. This includes scaling transfer between images of different resolutions for accurate characterization of the regional distributions of surface characteristics. To validate remote sensing ET estimates as well as scaling transfer products, I have intercompared remote sensing products with ground truth measurements. The systems I work on are so temporally and spatially variable that repeated field visits are essential to understand system behavior; therefore it requires field monitoring, sample collection, as well as numerical modeling.

 

 

Ongoing research I: Remote sensing algorithms and up- and down-scaling

 

The main objective of my doctoral research was to determine the spatio-temporal distributions of evaporation and soil moisture over heterogeneous landscapes in arid and semi-arid regions. My specific objectives were:

 

1.            Confirm and improve the performance of SEBAL for remote quantification of evapotranspiration rates from riparian areas in the southwestern United States.

2.            Conduct a sensitivity study of SEBAL for determination of the relative importance of each empirical relationship and assumption employed for quantification of the fluxes of the energy balance.

3.            Develop up- and downscaling approaches between Landsat7 and MODIS derived evapotranspiration and soil moisture maps for accurate characterization of spatio-temporal distributions of these variables.

 

My dissertation shows that SEBAL yields reasonable estimates for energy balance components in riparian areas in the southwestern United States and up- and down-scaled ET maps over the Middle Rio Grande Basin are in good agreement with ET maps directly derived from Landsat 7 and MODIS images. I like to expand my current SEBAL work to the environmental conditions of Kentucky with emphasis on drought monitoring using

optical remote sensing images acquired by the Landsat and MODIS systems. Both Landsat and MODIS images are now available free of charge. It is my goal to combine Landsat images with a high spatial resolution (30x30 m) together with MODIS images with a high temporal resolution (twice a day) for the accurate monitoring of drought in Kentucky.  

 

As a postdoctoral researcher at New Mexico Tech, I am in charge of the campaign to validate surface soil moisture maps of RADARSAT 2 with field soil moisture measurements. I will seek research funding to explore the use of RADARSAT 2 images for Kentucky conditions.

 

 Ongoing research II: Spatial Variability of Root Zone Soil Moisture across Scales

 

SEBAL estimated root zone soil moisture data were spatially aggregated and checked for power law behavior over a range of scales from 30 m to 15 km for Landsat and from 1 km to 28 km for MODIS images. Results of this study suggest that power law scaling of soil moisture in the middle Rio Grande area holds up to 106 m2 pixel size, but is no longer valid beyond that scale. Semi-variograms show an isotropic correlation structure and their sill and range are dependent upon the rootzone soil moisture conditions.

 

Ongoing research III: Detection of artifacts using thermal camera and GPR

 

As research assistant at New Mexico Tech, one of my main research topics other than thesis and dissertation subjects, was to determine the effect of environmental conditions on detection of buried land mines using ground penetrating radar (GPR) and thermal infrared camera.

 

At Murray State University I want to explore how the same techniques can be used for detection of archeological artifacts and features.

 

New research on hydrology remote sensing

 

I have a number of future research questions that I like to pursue at Murray State University:

-       How can SEBAL be employed for evapotranspiration predictions in humid climates under cloudy conditions combining optical and radar imagery?

-       How can scintillometer ground measurements of the sensible heat flux be used for validation of SEBAL using MODIS images?

-       How can RADARSAT 2 images be used under Kentucky conditions for measuring surface soil moisture?

 

Last updated August 2009
Sung-ho Hong