Geoscience Reference
In-Depth Information
fluxes result from direct, local interactions between a moving
atmosphere and the sea, that combine the lower limit of the
atmosphere and a player in the interaction, through the movement and
transformation of the air and water involved.
Figure 3.1.
Net annual mean
radiative flux (data from the
satellite ERBE, http://eos.atmos.washington.edu/cgi-bin/erbe/disp.pl?net.ann.)
(see color section)
In the atmosphere, the layer that interacts directly with the surface is
called the atmospheric boundary layer (ABL). Its thickness, above the
oceans, varies from several tens of meters to a maximum of 1,500-
2,000 m. The lowest part of this layer, called the surface layer (a few
tens of meters, less than 10 m over sea ice; estimated to be
approximately 10% of the height of the ABL), is the site of turbulent
exchanges, due to its contact with the surface. Strong gradients of
temperature, humidity and wind take place in this layer. Above, the
ABL can display a positive, neutral or negative stability: the transfers
of heat from bottom to top are easy, possible, or the transfer can only
occur downward, respectively. At its top, a transition layer separates it
from the free atmosphere, in which large-scale meteorological systems
take place.
