Geology Reference
In-Depth Information
(a)
(b)
(e)
4%
12%
20%
Ellesmere
Island
28%
36%
44%
52%
60%
JJ
E
Nares Strait
G
Greenland
DD
W
CIS Ice Chart
Jan. 14 2008
H
KK
Baffin Bay
DD
68%
76%
MM
FF
84%
92%
100%
MM
FF
HH
(c)
(d)
0.85
0.86
0.87
0.88
0.89
0.91
0.92
0.93
0.95
0.96
0.98
0.99
1.00
Figure 10.17
ECICE estimates of (a) MY ice concentration and its confidence level from using AMSR‐E observations
only and (b) AMSR‐E combined with scatterometer. The confidence level of the two estimates is shown in (c) and (d),
respectively. The corresponding weekly CIS ice chart is shown (e). (For color detail, please see color plate section).
Nares Strait to values between 20% and 60% in southern
latitudes (between 70° and 75°). The confidence level at
which MY ice concentration is produced is shown in
Figure 10.17c for using data from AMSR‐E only and
Figure 10.17d for using the combination of AMSR‐E
and QuikSCAT. It is rather low, and lower from using
the combination. That is perhaps due to the coexistence
of the two ice types (FY ice and MY ice) in the same
footprint.
Three sources of error can contribute to the measure-
ments: (1) weather and snow/ice growth conditions that
cause significant deviation of brightness temperature
(which implies surface emissivity) from the established set
of tie points, (2) atmospheric influences that add to the
measured brightness temperature from the surface, and
(3) system noise. The first two sources have been addressed
in many studies that evaluate the performances of differ-
ent algorithms. A brief synopsis of these two sources
along with the sensitivity of the estimated ice concentra-
tion to perturbations in brightness temperature is pre-
sented in this section.
Ice concentration from microwave observations is
affected by the variations of emissivity of the radiat-
ing layer. It varies as ice grows and in response to
10.2.2.2. Sources of Error and Sensitivity of Ice
Concentration Algorithms
Regardless of the physics involved in an ice concen-
tration retrieval algorithm, errors in the results can be
attributed to anomalies in the measured radiation.
