Dl hydrogr Z.40, 1987 H3 Klein Benthic storms 
93 
Table 3 
U h.. 
cm/s 
m 
2 0 
2 5 
5.0 
6 2 
10 0 
12 4 
15.0 
18 6 
20.0 
24.8 
The estimate (see Table 3) shows that the storms occur also within, oral least at the lop 
of the turbulent Ekman later. A vertical shift in the core position between 10 and 70 m a. h 
is evident in both figures, clue to the interface betacen BBL and the deep sea. Le Groupc 
Tourbillon [1983] established a similar phenomena in the Tottrbillon Eddy at the main 
pycnochnc. about 5° eastwards of the NOAIVIP area. 
Figure 4(17. 11. S3) shows a an ticyclonic vortex in lire northeastern part of the polygon 
and a small part of a cyclonic vortex in the southwest. The latter motes slowly (1 0 to 
1.5 cm/s) northeastwards and shapes the circulation pattern 8 days later on Not ember 25 
(see Fig 5) Its mean rotation period is about 9 days at 10 m a. b. and 12 days at 200 ma b. 
During NOANTP Tl, i. c. from April ’84 until September ’84. two storms occurred, 
labelled with C and D in Table 1. For this period, the strearnfunctions can be computed for 
a vert small polygon (ca. 28 km x 28 kin) at 70 m a b. only Again, the maps indicate the 
transit of a vortex 
A deep reaching meddy 
The strearnfunctions in Fig 6 show a cyclonic vortex, again with strong bottom intensi 
fication This vortex can be tracked for scteral days during October 'S3, Its transit velocity, 
estimated from the displacement of the core, amounts to about 2 to 6 cm/s. The net 
movement is westwards, but not straight ahead. 
The vortex is also evident in the CTD-data of the ’Meteor" 65 cruise. September 
October'S3. Evaluating the data of the hydrographic survey (S I CTD casts in a 120 n. m. >: 
120 n m. rectangle), S eh a uc r [1987] established and described a cyclonic vortex with the 
hydrographic properties of a meddy With regard to the geopoicntial between 1600 and 
4000 dbar, the meddy is embedded in a field of other cyclonic and anticyclomc features (see 
Fig 7) The tl\ nanne signal is centred at 1600 dbar. but the anomalies of potential tempera 
ture and density are visible down lo ihe bottom. Using also the current meter data of the 
French TOPOGULF-moorings, Schauer estimated the transit velocity of the meddy as 
being between 1.2 and 5.8 cm/s The geostrophic velocity in the meddy at 1600 m depth is 
greater than 10 cm/s. 
Dispersion of virtual particles 
The sampling interval of the current meters is 60 minutes for the ACNTS’s, respectively 
30 minutes for the Neil-Brown instruments. Therefore, the coefficients «.„of stream function 
I¡i can be determined for every full hour Due to the filling of the coefficients to direct 
measurements, the resulting streamfunction pattern includes the effect of momentum flux 
u’i ’. The calculation of a "time senes” of the coefficients facilitates the simulation of the 
quasi-lagrangian transport of virtual passive particles.