Investigating the Influence of Surface Heat Flux on the North Atlantic Circulation and Global Climate
OCCI Funded Project: 2007
Abstract
The
circulation in the North Atlantic Ocean greatly
influences the climate of the surrounding countries. The high heat capacity of the large-scale
ocean currents makes it possible for the Atlantic water to warm the atmosphere
in the surrounding countries quite significantly. Understanding how the ocean responds to
variations in global forcing is, naturally, an important ingredient in any
climate scenario, especially those dealing with the North
Atlantic sector. In particular, I
propose to answer the following question: How do changes in the surface
buoyancy forcing of the North Atlantic Ocean influence
the strength of the horizontal flow between the equator and the polar
regions? I propose to investigate, both
analytically and experimentally, the response of such horizontal flow, and
consequently of the North Atlantic
overturning circulation, to changes in the surface buoyancy forcing in the
presence of background rotation. I will
conduct laboratory experiments using a new infrared technology which allows a
free adjustment of the temperature in the tank.Fresh water will be heated from above by an infra-red lamp, and then, as
the warm water will move away from the heat source, it will naturally cool at
the surface. This forcing is similar to
that in the ocean, which absorbs solar radiation in a relatively thin surface
layer at low latitudes and loses most of this energy through evaporation at
higher latitudes. New scaling laws will
also be developed in which the length and temperature scales are obtained as a
function of the radiative forcing, rather than being imposed by the geometry of
the experiment. Previous studies used
fixed temperature and/or fixed heat flux forcing. The novelty of the proposed study is the
presence of background rotation together with the new forcing technique
described above. Finally, the proposed
research will assist in the understanding of how future or past changes in the North
Atlantic Ocean surface buoyancy forcing affect the
overturning circulation and the climate of the surrounding regions. The project will be performed in
collaboration with a visiting European scientist.