Title: Ocean's Slow Burn Process and the Ocean Modeling for Climate Research

Speaker: David Dietrich (President, AcuSea, Inc.) & C. Aaron Lai (Los Alamos National Laboratory)

Date/Time: Thursday, January 13, 2005, 1:00-2:00 pm

Location: Building 980, Room 95 (Sandia NM)

Brief Abstract: Dr. Dietrich will present a detailed numerical model of the North Atlantic Ocean that once required supercomputing power and that can now be done using a personal computer. This is because of advances both in hardware and ocean modeling. This permits reliable and efficient studies addressing a variety of ocean-related climate change theories, including abrupt climate change. Low numerical dispersion and dissipation are needed to maintain the narrow, thin deep current water properties (temperature, salinity and kinetic energy) with sufficient intensity during their 5-10 year flow from their source regions (northern seas and Arctic Ocean) to realistically affect the Gulf Stream separation and path, which is crucial in climate change studies. Results will be shown from a robust 4th-order-accurate ocean model based on collocated (non-staggered) control volumes, which achieves this numerically demanding task using a 2 GHz P4 PC.

Dr. Lai will present the finding of "ocean's slow burn process" and its impacts on climate research. The importance of the deep currents is amplified by their effects on the dissociation of big methane hydrate deposits on the continental shelf/slopes. Methane hydrates can dissociate into methane bubbles and water. Bacteria metabolize the methane, starting a food chain that results in CO2, water and heat as final products. This kind of heat remains trapped by the overlying warm water as it spreads laterally. Eventually, it enters the Arctic Ocean, where rapid deep warming has been detected recently. A detailed analysis of the ocean biogeochemical data collected during the World Ocean Circulation Experiment (WOCE) 1987 - 1998 had revealed the evidences of ocean's slow process. The "Slow burn process", as described above, depletes dissolved oxygen in seawater. The observation data match the predicted amount of oxygen depletion very well. Therefore, we can estimate the amount of heat generated in the slow burn process. This finding shows that there is an internal heat generator in ocean that can significantly alter the physical/dynamical process of ocean circulation. It also offers an explanation for the observed warming of intermediate depth seawater since 1955. The impacts of this ocean's slow burn process on climate change will be discussed in the context of the interactions among the atmosphere, sea ice and the oceans.