Publication Date:
2015-11-23
Description:
The porosity of sea ice is a fundamental physical parameter
that governs the mechanical strength of sea ice and the mobility
of gases and nutrients for biological processes and biogeochemical
cycles in the sea ice layer. However, little is known about the
spatial distribution of the sea ice porosity and its variability between
different sea ice types; an efficient and nondestructive
method to measure this property is currently missing. Sea ice
porosity is linked to the bulk electrical conductivity of sea
ice, a parameter routinely used to discriminate between sea
ice and seawater by electromagnetic (EM) induction sensors.
Here, we have evaluated the prospect of porosity retrieval of
sea ice by means of bulk conductivity estimates using 1D multifrequency
EM inversion schemes. We have focused on two inversion
algorithms, a smoothness-constrained inversion and a
Marquardt-Levenberg inversion, which we modified for the
nonlinear signal bias caused by a passive bucking coil operated
in such a highly conductive environment. Using synthetic modeling
studies, 1D inversion algorithms and multiple frequencies,
we found that we can resolve the sea ice conductivity within
+-0.01 S∕m. Using standard assumptions for the conductivity-
porosity relation of sea ice, we were able to estimate
porosity with an uncertainty of +-1.2%, which enables efficient
and nondestructive surveys of the internal state of the sea ice
cover.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
isiRev
Format:
application/pdf
