Many recent observations have described fronts in the interior of the
ocean at locations far away from any lateral boundaries. Some of these
fronts are observed to be associated with considerable mass transport
s, which suggests that they participate importantly in setting the wat
er mass structure of the ocean interior, and represent considerable lo
cal departures from linear Sverdrup dynamics. In this paper, a simple
analytic theory of interior fronts is developed. The main features of
this theory are that the fronts are highly inertial and anisotropic, a
nd reside on the edge of a somewhat larger scale interior inertial rec
irculation. The recirculation is taken to be modonlike; the dynamic he
ight difference across the edge of the recirculation supports an inter
ior jet, which is clockwise around the edge of the recirculation and c
arries water from the subpolar into the subtropical gyre. Unlike in pr
evious theories of interior fronts, all of the transports, both in the
large-scale and the fronts, are ''anomalous'' and in excess of any wi
nd-driven transport. The fronts themselves represent interior, deforma
tion-scale boundary layers, which are necessary to smoothly join the b
aroclinic parts of the inertial recirculation and the sluggish Sverdru
p zones. The authors speculate on the role of these dynamics in the LD
E jet.