|  |
Program |
 |
| |
 |
General Session 1: Physical oceanic processes: Dynamics and physical-biological-biogeochemical interactions |
| |
|
|
Dissolved oxygen: A powerful tracer for changes in physical dynamics, a case for the East Sea (Japan Sea)
Tuesday 10th @ 1200-1215
Multi-function Hall
K-R Kim* , GIST College, GIST, Gwangju, Korea
D-J Kang, KIOST, Gyeonggi-do, Korea
S Park, Kyungpook National University, Daegu, Korea
D Hahm, Pusan National University, Busan, Korea
T Roh, KIOST, Gyeonggi-do, Korea
T Lee, Pusan National University, Busan, Korea
S-T Yoon, Seoul National University, Seoul, Korea
S-H Nam, Seoul National University, Seoul, Korea
K-I Chang, Seoul National University, Seoul, Korea
Presenter Email: krkim@snu.ac.kr
|
| The East Sea has been in dramatic changes for the last 60 some years possibly in association with recent global climate changes, clearly manifested by increases in temperature over whole water column. Most conspicuous changes are observed in Dissolved Oxygen (DO) profiles, showing unusual rapid decreases in concentration (~7μM per decade) in deep and bottom waters. Changes in vertical profiles also suggest that DO minimum depth has been continuously deepening from shallower than 1000 meters in 1970s to deeper than 2000 meters in 1990s. The vertical profiles also show dramatic changes, especially the appearance of distinct subsurface minimum at ~ 1500 meters during 1990s. There are coherent historical data showing that these changes are accompanied with changes of deep water structure. We developed a simple box-model called MBBM (Moving Boundary Box Model) to decipher and obtain insights on all these changes. The model is based on 4 vertical-layer ocean model, which can accommodate the changes in volume of each layer observed in historical data. The model, calibrated by tritium and CFCs data, clearly demonstrates that most of chemical changes, especially the one observed in DO, can be explained by simple readjustment of ocean dynamics of deep water formation; chimney formation mode vs. brine formation mode. The change of deep water formation, probably associated with recent global warming, clearly indicates that physical dynamics and biogeochemistry are closely connected. Recent observation shows another type of changes in DO structures, slowdown of decreases in DO concentrations in deep waters and volume changes in bottom waters. Implications of MBBM in this newly discovered aspect will be further discussed at the meeting. Will the East/Japan Sea become an anoxic sea in the next century? (2004). Kang, D.-J., J.-Y. Kim, T. Lee and K.-R. Kim, Marine Chemistry. 91, 77-84. A Moving-Boundary Box Model (MBBM) for oceans in change: An application to the East/Japan Sea (2003). Kang, D.-J., S. Park, Y.-G. Kim, K. Kim and K.-R. Kim, Geophysical Research Letters, 30(6), 1229, doi:10.1029/2002GL016486. Warming and Structural Changes in the East (Japan) Sea: A Clue to Future Changes in Global Oceans? (2001). Kim, K., K.-R. Kim, D.-H. Min, Y. Volkov, J.-H. Yoon and M. Takematsu, Geophysical Research Letters, 28(17), 3293-3296. |
|
|
|
|