Research-past

More of Dong-Ha Min’s Research Interests

Background:

Research Associate – I have worked with Prof. Klaus Keller at the Pennsylvania State University. My research focused on how to detect and understand changes in the ocean’s geochemical and physical processes caused by global warming, and how this can be used to better predict the global change and impacts. Specific projects include (i) the analysis of temporal trend of dissolved oxygen in the Southern Ocean during the past decades to detect the ocean’s response to climate change, (ii) the development of integrated global carbon cycle model with improved parameterization of uncertainties, and (iii) the interpretation of general circulation model results of the future climate changes patterns due to a North Atlantic thermohaline circulation collapse.

Postdoctoral Research Associate – I worked with Dr. Mark Warner at the University of Washington on integration and interpretation of WOCE CFC data for the Southern Ocean to better understand the recent ventilation patterns and rates. I also carried out the basin-wide measurement of CFCs in the East Sea (Sea of Japan) in 1999 with Mark Warner and identified the counter-intuitive higher-oxygen and lowest-CFC content bottom water produced by dramatic changes in deep water ventilation rates and oxygen concentrations during the past several decades. A widely distributed CFC-maximum in intermediate water, and unexpectedly high-CFCs in bottom water in the Yamato Basin were the additional new findings. The first CCl4 (carbon tetrachloride) measurements carried out in the East Sea showed substantial removal in the warmer upper waters while insignificant loss in the cold deep waters. During this period, I collaborated with Dr. John Bullister at NOAA/PMEL and Prof. Ray Weiss at Scripps Institution of Oceanography to elucidate the anomalous bottom-intensified CFCs in the Southern California Borderland Basin, and to carry out a pilot groundwater tracer study in the Vashion Island, WA.

Ph.D. – I worked with Prof. Ray Weiss at SIO and, I studied large-scale ocean circulation and ventilation using CFC tracers, and participated in several oceanographic expeditions including WOCE. My dissertation research included the first application of the recent decreasing trend of CFC-11/CFC-12 ratio to estimate CFC ages of ocean upper waters. Based on the CFC observation from the WOCE/ACCE A24 expedition in the subpolar North Atlantic in 1997, I suggested that the rapid surge of Labrador Sea Water (LSW) into the Irminger Basin might occur only during active winter convection years and this short route is disconnected from the main circulation path during the remaining period. In a recent collaborative study with M. Rhein (U.Bremen) and others, we have shown the LSW distributions and calculated the formation rates (4.4-5.6 Sv) during the late 1990s. In 1996, I measured CFCs in the East Sea during the Circulation Research of East  Asian Marginal Seas (CREAMS) program in collaborations with my Korean colleagues. It was an exciting experience to lead the CFC program from overseeing the logistics to its successful  completion of a solo shipboard measurements. A large-scale tracer and tracer age field was obtained in this region for the first time. I am currently developing a model to understand the dramatic changes in deep-water ventilation rates and water properties in the East Sea during the  past several decades in context of recent climate change such as global warming and the Pacific Decadal Oscillation. During the WOCE I3 expedition in the Indian Ocean in 1995, I have located the first CFC trace of northward spreading Antarctic-origin bottom water in the Mascarene Basin at 20ºS. Time-series CFC measurements of the thermocline waters off California showed that the CFC ages have been constant over a 12-yr period even though there was a significant impact of El Niño on the tracer burden.

Last Update: 5/3/2005