Di hydrogr Z 40. I9S7 H.3 Klein. Benthic storms 
91 
The storms occur both at moorings near topographic features and in areas with only modest 
slopes. Similar events have been reported by Hollister and McCave (1984] from a 
region underthe Gulf Stream. They supposed that theorigin of high abyssal kinetic energy 
is related to high surface kinetic energy, i c the Gulf Stream or its rings. In the NOAMP 
area, the benthic storms are probably due the synoptic eddies: as tor example surveyed 
during "Meteor" 70 cruise (Kupferman. Becker. Si turnon s et al [1986]. M i 11 ci 
st a e d t [1987]). Such storms, especially in connection with deep reaching vortices, are 
important mechanisms for the dispersion of particles: they enhance the height of the BBL 
and the amount of A m and A.',., and enable the particles to pass the interface between BBL 
and the interior of the deep ocean. 
Divergences caused by deep reaching eddies or topographic features maintain the 
exchange between both layers (eddy or topographic pumping). Fig. 3 shows a part of the 
low-pass filtered lime series of mooring K2 (10 m a. b ). with storm B of Table 1 The 
original data exceed 20 cm/s during thestorm. The mean vaiucofthc wholcbmonth record 
is 4.8 cm/s 
t 
Fig. 3 Time series ol amount of velocity I r I and direction a, of mooring K2, 
lOrna.b, with storm B 
Benthic storms and deep reaching vortices during NO AMP I and II 
From September ’83 until April ’S4 (NOAVIP I), al! moorings - with the exception of 
mooring K5 - were located in the abyssal plain westwards of the major topographic feature, 
the “Großer Dreizack" (Fie in rich [1986]) In the long-term mean, there is a strong 
westward flow in the northern part of the plain (at L2, K3, LI) and a weak counter current 
in the south at Kl, probably induced by the topography. At 10 m and 70 m a. b. the 
instruments yield good data for 5 current meters, in 2(10 m a. b. for 6 current meters (sec 
Table 2). 
Tab le 2 
distance from moorings w ith good 
bottom data 
m 
10 
Kl. K2. 
K4. LI. 
L2 
70 
Kl. 
K3, K4, LI. 
, L2 
200 
Kl, K2. 
K3, K.4. LI. 
, L2