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JOURNAL OF PHYSICAL OCEANOGRAPHY 
VOLUME 50 
TABLE 2. Partitioning of the DSOW transport (Sv) by water masses and current components. The values in parentheses include the 
unresolved portion on the Greenland shelf (0.54 Sv). 
Currents 
Shelfbreak EGC Merged NIT-separated EGC Total 
Water masses 
Arctic-origin water 0.41 + 0.06 
Atlantic-origin water 0.33 + 0.06 
Other water masses 0.11 + 0.02 
Total 0.85 + 0.14 (1.39 + 0.14) 
1.31 + 0.09 
0.62 + 0.04 
0.22 + 0.02 
2.15 + 0.15 
1.72 + 0.15 
0.95 + 0.10 (1.49 + 0.10) 
0.33 + 0.04 
3.00 + 0.29 (3.54 + 0.29) 
of Macrander (2004) is roughly 0.40 Sv, which has been ac- 
counted for in the estimates of Jochumsen et al. (2012). 
Results from a mooring on the Greenland shelf (30km west 
of the trough) implied a similar value of 0.50 Sv (Jochumsen 
et al. 2017) [the mooring array used by Harden et al. (2016) 
encompassed the DSOW on the Greenland shelf]. Linearly 
extrapolating our mean section of Fig. 4d to the Greenland 
coast gives a value of 0.54 Sv for the missing transport, which 
is in line with the estimates above. Thus, our adjusted total 
:ransport of 3.54 + 0.29Sv is comparable to the previous 
DSOW transport estimates. 
Our hydrographic and velocity data provide the opportunity 
LO partition the overflow transport by water masses. To do this, 
we applied the same water mass end-member technique of 
Mastropole et al. (2017) to our 22 occupations. Mastropole 
et al. (2017) defined four endmembers: ALOW, ArOW, Polar 
Surface Water (PSW), and Irminger Water (IW). These are 
shown in the 7 plane in Fig. 5a [see Fig. 6 of Mastropole et al. 
(2017) for a geographical context]. Mastropole et al. (2017) 
devised two mixing triangles, one of which used the first three 
water masses, and the other using the latter three water masses 
(Fig. 5a), the assumption being that AIOW does not mix with 
Irminger Water. For each station of a given occupation we 
computed the corresponding end-member percentages, then 
gridded these to make vertical sections. The mean sections of 
vercentage for the four water masses are shown in Fig. 5. 
The ArOW dominates the deep trough where the merged 
NIJ-separated EGC is located, accounting for close to 100% of 
ıhe overflow water near the bottom (Fig. 5b). By contrast, the 
AtOW percentage is highest in the vicinity of the Greenland 
shelf break, with large values in the shelfbreak EGC (Fig. 5c). 
Note, however, that the percentage of ArOW is comparable to 
:hat of the AtOW in this region—this further indicates 
nerging/mixing of the three branches. For the other two end 
members, the Polar Surface Water and Irminger Water, the 
nean percentages are quite small in the overflow water 
(Figs. 5d,e). While there is some section to section variability in 
ArOW and AtOW percentages for the merged NIJ-separated 
EGC and shelfbreak EGC, the standard deviations are only 
ıetween 6% and 8%. 
Using the mean water mass end-member percentage sec- 
ions (Fig. 5) in conjunction with the mean velocity section 
(Fig. 4d), we get a transport of 1.72 + 0.15 Sv for ArOW and 
3.95 + 0.10Sv for AIOW (Table 2). I£ we assume that the 
unresolved portion of the flow on the Greenland shelf is pre- 
dominantly AtOW, this boosts the transport of this water mass 
to 1.49 + 0.10 Sv. Hence. we conclude that the mean transports 
of the two types of overflow water are comparable in 
Denmark Strait. The remaining transport (0.33 + 0.04 Sv) 
zorresponds to the small contributions from the Polar Surface 
Water and Irminger Water getting mixed into the top of the 
overflow layer. 
As noted in the introduction, Harden et al. (2016) parti- 
:joned the overflow transport into the three flow branches us- 
ng data from the upstream Blosseville Basin mooring array. 
sing four shipboard occupations of the same line, Väge et al. 
2013) did the same partitioning with generally consistent 
results. While the two bands of enhanced southward flow 
N our mean velocity section reflect the shelfbreak EGC 
and merged NIJ-separated EGC, respectively (Fig. 4d), the 
degree to which all three branches have merged/mixed in the 
strait makes it impossible to do precise partitioning here. It is 
ıonetheless instructive to consider the geographical distribu- 
(on of the overflow transport. 
We specify the boundary between the nominal shelfbreak 
3GC and merged NIJ-separated EGC to be —25km (ie., 
he location of the velocity minimum between the two 
Jands, Fig. 4d). It follows that the shelfbreak EGC transports 
J.85 — 0.14Sv, while the merged flow accounts for 2.15 + 
).15Sv (Table 2). By comparison, Harden et al. (2016) calcu- 
:ated 1.50 + 0.16 Sv for the shelfbreak EGC and 2.04 + 0.16 Sv 
[or the merged flow. It is safe to assume that the inshore flow 
an the Greenland shelf at the Lätrabjarg line originated from 
:he shelfbreak EGC upstream (recall that Blosseville mooring 
array captured all of the overflow water on the Greenland side, 
which was confined to the region of the shelf edge). This in- 
zreases our shelfbreak EGC transport to 1.39 + 0.14 Sv, in line 
with the Blosseville Basin estimate. Hence, our total transport, 
as well as the geographical distribution of transport across the 
strait, is consistent with Harden et al.’s (2016) upstream par- 
itioning. With regard to the overflow water masses, our mean 
zections (Figs. 4d and 5) indicate that the band of flow at the 
shelf break transports comparable amounts of ALOW and 
ArOW, while the band of flow on the western flank of the 
:rough transports roughly twice as much ArOW as ALOW 
“Table 2). Again, this attests to the significant degree of 
sxchange between the flow branches as they converge in 
Denmark Strait. 
4. Dominant variability 
We now consider the section to section variability in our 
22 occupations, which is a reflection of mesoscale processes. 
Using a mooring in the center of the Denmark Strait trough, 
von Appen et al. (2017) showed that the two pronounced 
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