Geology Reference
In-Depth Information
0.08
0.07
0.06
0.05
0.04
0.03
0901-OW
0904-OW
0912-OW
0.02
0.01
0917- OW
0.00
0923-OW
0901-ice
0904-ice
0912-ice
-0.01
-0.02
0917-ice
-0.03
0923-ice
-0.04
-0.1 -0.09 -0.08 -0.07 -0.06 -0.05 -0.04 -0.03 -0.02 -0.01 0.01
GR
36
V
19
V
0
0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1
Figure 10.15
Distribution of data points from pixels of OW and pixels of ice plotted in the GR
36
V
19
V
and GR
23
V
19
V
space
showing the thresholds used to filter out OW pixels. Labels in the legend are based on ice concentration estimates from
CIS Radarsat analysis. Data were obtained from AMSR‐E images in the Arctic on different days in September 2002 as
indicated in the legend [M. Shokr, unpublished data]. (For color detail, please see color plate section).
and both determined by the salinity and the sea ice
composition within the penetration depth of the signal.
Combining passive and active microwave data in an ice
concentration algorithm reveal information that can-
not otherwise be revealed from using each sensor sepa-
rately. An example of the ECICE output is presented
in Figure 10.16. The input AMSR‐E and QuikSCAT
data (shown in Figure 10.14) were obtained from the
reconstructed daily averaged data from AMSR‐E and
QuikSCAT. The data are provided through a product
called Scatterometer Image Reconstruction (SIR). It is a
gridded product projected onto a polar stereographic
grid [
Early and Long
, 2001]. It is available from Microwave
Earth Remote Sensing (MERS) Laboratory of Brigham
Young University (BYU).
Figure 10.16 shows the concentration of each ice
type and the total ice concentration in the Arctic above
60° latitude on 17 October 2007. The gray color (not
shown in the color bar) corresponds to OW as defined
by the OW filter. The pixel size is 4.45 × 4.45 km
2
. A total
ice concentration of 100% can be seen extending from the
Greenland side of the Arctic Ocean into the center of the
Arctic Ocean with vast regions of OW extending from
the Beaufort Sea to the Laptev Sea. By this time of year
(17 October) the ice cover is expanding and high concen-
trations of YI can be seen at the leading edge of the ice
cover facing the Eastern Siberian and Chukchi Seas. High
concentrations of thicker FY ice trail the YI inside the
expanding ice pack. The MY ice is confined mainly to the
North American side of the Arctic Ocean with a stream
extending toward Severnaya Zemlya and the Laptev Sea.
The figure shows how the results from ECICE could
assist in determining the area occupied by each ice type.
Ice type concentration (not only total ice concentra-
tion) is becoming more important as seasonal ice types
are replacing the rapidly decreasing perennial ice in the
Arctic. Currently, seasonal ice covers more than two
thirds of the Arctic Ocean, up from one third in the
1990s [
Kwok et al
., 2009].
The difference between the ECICE product of MY
ice concentration when using the passive microwave
AMSR‐E only and AMSR‐E combined with QuikSCAT
is shown in Figure 10.17. Using AMSR‐E only involved
T
b
36
h
and PR
36
while the combination with QuikSACT
adds
0
. The output from using the combina-
tion indicates the presence of MY ice concentration,
0
and
hh
vv
