Alpine Summer School 2010 - Course XVIII

"Buoyancy Driven Flows"

to be held in Valsavarenche, Valle d'Aosta (Italy), 21-30 June, 2010

Deadline for applications: April 26th, 2010:

http://to.isac.cnr.it/aosta/

Buoyancy is one of the main forces driving flows on our planet, especially in the ocean and atmosphere. Buoyancy driven flows encompass a wide spectrum of geophysical flows that range from buoyant coastal currents to dense overflows in the ocean, and from avalanches to volcanic pyroclastic flows on the Earth's surface.

The ocean displays an exceptionally wide range of buoyancy-driven flows. Globally, buoyancy-driven currents are primarily responsible for the redistribution of fresh water throughout the world's oceans and play a key role in the global ocean circulation and climate change through their impact on deep-water formation. Formation of dense water usually occurs in marginal seas which are either cooler (at high latitude) or saltier (due to a greater rate of evaporation). The dense water enters the ocean as an entraining gravity-driven current (i.e. an overflow), descending the continental slope (e.g. the Mediterranean outflow into the North Atlantic) and entrains ocean water as it descends. The final properties of dense current water masses are of global importance since they become part of the global ocean circulation. An understanding of the detailed flow behavior and the entrainment/mixing by such dense currents is therefore critical to our understanding of the stratification of the oceans. Finally, buoyant coastal currents transport fresh water, heat, nutrients, sediments, biogeochemicals, pollutants, and biological organisms along many continental shelves and, hence, have important impacts on ecosystems, fisheries, and the coastal circulation.

The lectures will first give a broad overview of the current state-of-the-art research in buoyancy-driven flows and will be put in the context of a wider range of geophysical problems (avalanches, volcanic flows, atmospheric flows, etc.). Then, more specific lectures will focus on the importance of correctly representing processes than are not currently resolved in the ocean component of climate models. Given the impact of buoyancy flows on the ocean circulation and the earth's climate, we consider it timely to bring together leading scientists to summarize our present theoretical, experimental, and modeling understanding of buoyancy-driven flows.

One major objective of the school is to expose young graduate students and recent Ph.D.s to the importance of buoyancy-driven flows in the ocean circulation and in the present day climate from a combined theoretical, experimental, and modeling point of view. The lecture notes will be published as text book.