Geology Reference
In-Depth Information
are generated: (1) ice reconnaissance charts, (2) image
analysis charts, (3) daily ice analysis charts, (4) weekly
regional ice charts,(5) 30 day extended forecasts, and (6) a
seasonal outlook. In addition, a number of publications
are produced to provide ice climatology records. The
most popular product is known as Ice Atlas; a collection
of SAR mosaics of Arctic ice cover in January (some
aerial reconnaissance maps are incorporated in the mosa-
ics). The products are described briefly in this section.
More information can be found in
MANICE
[2005].
In order to place the products in an operational context,
they are grouped into categories based on the temporal and
special scale required for the information. The categories
include (1) tactical ice information, (2) short‐term planning,
(3) medium‐term planning, (4) long‐term planning, and (5)
climatological information. Tactical information is pre-
sented in a few forms that include ice reconnaissance charts
(also called ice observation charts), generated at scale
1:1,000,000. Charts are based on visual observations from
ships, helicopters or aircrafts. Tactical information forms
also include image analysis charts from a wide range of
remote sensing imagery data, the most notable is Radarsat.
These charts are produced at the same spatial resolution of
the data or slightly coarser (e.g., 200 m from Radarsat
ScanSAR data). The daily ice analysis charts, a third
form of tactical information, are generated at a scale of
1:2,000,000. They lack the accuracy of identifying individ-
ual ice floes. Nevertheless, they can be used to guide marine
navigators to areas where more favorable ice conditions can
be found (although they are not really intended to be a
source of information for tactical navigation).
For short‐term planning, weekly regional ice analysis
charts can be used. They provide forecast information at a
scale of 1:4,000,000. The information contains descrip-
tions of ice floe sizes, ice types, concentrations, and air
temperatures compared to the mean temperatures over
the past 7 day period. Medium‐range planning depends
on the 30 day extended forecasts, which are produced
twice a month (on the 1st and 15th). They predict ice con-
ditions in three regions: Hudson Bay and approaches,
eastern Arctic, and western Arctic (Figure 11.1). Long‐
term planning can be performed using the seasonal out-
look product. This is generated in early June to describe
the expected ice conditions for the Arctic summer and
beyond. This assists marine operators in planning their
summer shipping activities in the Arctic.
The Canadian Coast Guard's icebreakers work in the
most hazardous ice conditions, including thick FY and
MY ice in the Arctic. In order to accurately identify loca-
tions of such hazardous ice along a ship route, CIS pro-
vides alternatives for ice charts to the CCG icebreakers.
One alternative is the Ice Service Specialists (ISS) who are
assigned on the larger CCG icebreakers. The specialists
are responsible for receiving airborne radar and satellite
imagery and carrying out visual analysis to identify loca-
tions of hazardous ice types. Another alternative is the
airborne missions with SLAR system to support detailed
routing of Coast Guard icebreakers and merchant ships.
In addition, the missions are used to validate analysis of
satellite imagery data. The ISS also carry out tactical ice
reconnaissance from helicopters that take off from land-
ing pads on icebreakers to explore the ice in the vicinity of
the ship. A document was compiled by CCG to provide
the crew of vessels transiting Canadian ice‐covered waters
with the necessary understanding of the regulations, ship-
ping support services, hazards, and navigation techniques
in ice [
Canadian Coast Guard
, 2012].
11.2.1. Coding Ice Information in Ice Charts
Ice information presented in any type of CIS charts is
coded into what is known as the “egg code.” This code
had been suggested by the Canadian ice forecasting
agency in the 1950s and endorsed later by the World
Meteorological Organization. It has become widely used
in ice monitoring centers ever since. Ice charts can be
generated directly by ISS during field observations from
aerial, shipboard, or coastal platforms or through visual
analysis of satellite images in the CIS's operational floor
in Ottawa by qualified ice analysts.
The egg code (Figure 11.6) contains information about
total ice concentration (
C
t
), ice types (
S
a
,
S
b
and
S
c
), partial
concentration of ice types (
C
a
,
C
b
, and
C
c
), and forms of
ice (
F
a
,
F
b
, and
F
c
). The first line in the code represents the
To tal ice
concentration
C
t
Partial ice
concentration
C
a
C
b
C
c
C
d
Stage of
development
S
a
S
b
S
c
S
o
S
d
S
e
F
b
F
b
F
a
F
b
F
c
From of ice
Figure 11.6
Egg code of ice information assigned to subjec-
tively delineated polygons in operational ice charts.
