Sack Lunch Seminar (SLS)

SLS: Rui Xin Huang - WHOI
Date Time Location
January 26th, 2011 12:10pm-1:10pm 54-915
Adiabatic density surfaces – the only truly neutral surfaces


A new family of surface, the adiabatic density surface, is introduced for the
world ocean. This surface is defined as the depth at which the given water
parcel can arrive through adiabatic movements, without changing its salinity and
entropy. For a water parcel taken at a given station and pressure level, the
corresponding adiabatic surface can be defined through very simple calculation.


This family of surface is the only neutrally buoyant surface in the world ocean,
and other surfaces different from this family of surface are not truly neutrally
buoyant. However, even on this surface, only the water parcel sits on the origin
can travel to other parts of this surface. Other water parcels sitting on
locations other than the origin of this surface cannot exchange their positions
through adiabatic and isentropic movements. If two water parcels on this surface
exchange their position, the total gravitational potential energy in the ocean
must be changed. In this sense, thus, neutral surfaces on which parcels can
freely exchange their positions do not exist in the world ocean. The similarity
and differences of the adiabatic density surface, the potential density surface,
and the so-called neutral density surface are compared in details.