Geoscience Reference
In-Depth Information
Fig. 2.5
Timeseriesoftheleadingcoefficients ofthecomplexdemodulationfittingforseven days
inSeptember, 1998. For
V
0
, up is north. The inertial phasor represents theamplitude and phase of
theclockwise rotatinginertialvelocity. The initialorientationof
S
cw
isarbitrary
Fromthe continuitycondition
0
∂
w
∂
∇
·
M
=
−
z
dz
z
bl
To an observer on the ice, the vertical velocity at the bottom of the boundarylayer
isthenproportionaltothecurlofthesurfacestress
1
f
∇
×
τ
0
w
pyc
=
(2.26)
In March 1998, at the SHEBA project in the central Arctic, we observedan up-
welling event apparently related to intense local ice deformation (McPhee et al.
2005). Late in the afternoon (local time, UT—9h) of March 19, the ice floe on the
starboardof the ship, wheremostof theinstrumentsystems were deployed,shifted
forward by several hundred meters.
2
During this time, we measured turbulent heat
flux in the upper partof the boundarylayer that was at least an order of magnitude
greater than at any other time during the year-long deployment; enough to cause
significantbasalmeltingwhentheiceisnormallyatitscoldest.Theparticularevent
thatoccurredonMarch19(day78of1998)waspartofamorewidespreadperiodof
2
A time-lapse video of the ice shear taken from the ship's bridge was shown on the CBS Nightly
News.
