A common feature of one-dimensional streamtube models is that the pressure
gradient includes only the effect of the density difference between the plu
me and the ambient water on a sloping bottom. Variations of the streamtube
height and density along the flow path are thus neglected. In the present p
aper a streamtube model is used to highlight the assumptions underlying the
simplification and to obtain the limitations this prerequisite presents. T
he results indicate that the parameter range for which the simplification i
s applicable is largest when the initial outflow is parallel to the isobath
s. More specific limits are given for three major outflows - the Mediterran
ean, the Faroe Bank Channel and the Denmark Strait outflow. (C) 2000 Elsevi
er Science Ltd. All rights reserved.