Manual of Ice (MANICE): chapter 4

Chapter 4: Iceberg Messages

• 4.1: Iceberg Coding and Message Preparation
• 4.2: Iceberg Coding Tables
• 4.3: Notes on Iceberg Coding Procedures
• 4.4: Examples of Iceberg Coding Reports

This chapter describes the iceberg information depicted on the observed ice chart as generated from either a ship or an aircraft in a message format.

Since Canada is in the northwestern quadrant of the globe, please note that all latitudes and longitudes are degrees North and West respectively. Also note that all times are in Coordinated Universal Time.

4.1 Iceberg Coding and Message Preparation

An iceberg reporting code has been developed by the Meteorological Service of Canada and International Ice Patrol, to allow for exchange of digital iceberg information and to enable computer-assisted manipulation of volumes of iceberg observations into one complete iceberg analysis. The iceberg code follows standard coding practices and iceberg nomenclature of the World Meteorological Organization and supplements codes that exist in World Meteorological Organization. It provides for the reporting of all iceberg parameters, the area of surveillance and the factors that influence both visual and radar iceberg detection.

Listed below is the basic format for the iceberg message, with the following sections describing each component. Notes referred to in the code descriptions appear in Section 4.3 (following the Iceberg Coding Tables section).

Iceberg Message:

IBXXN CCCC YYGGgg
PPPP P_tN_rN_rN_rN_r YYMMJJ

00000
Q_cL_aL_aL_aL_aL _a L_oL_oL_oL_oL_o ZGGgg 1C_sAAA 2V_IV_I 3RlRlRlR_rR_rR_r 4D_sD_sH_sH_s

11111
(SSSS) (I_dI_dI_dI_d) C_IGGgg L_aL_aL_aL_aL_a L_oL_oL_oL_oL_o 01C_iS_iS_h
(1C_lLEN 2C_lWID 3C_lHEI 4C_lDRA 5C_lDIR 6C_lSPE)

22222
(SSSS) C_IGGgg L_aL_aL_aL_aL_a L_oL_oL_oL_oL_o N_tN_tDrr nnC_iS_iS_h (nnC_iS_iS_h)

33333
C_IGGgg L_aL_aL_aL_aL_a L_oL_oL_oL_oL_o L_aL_aL_aL_aL_a L_oL_oL_oL_oL_o nnnnD ( nnnnD)

44444
C_IGGgg L_aL_aL_aL_aL_a L_oL_oL_oL_oL_o (1m_am_am_om_o) 2N_tN_tN_tD nnC_iS_iS_h (nnC_iS_iS_h)

55555
(SSSS) C_IGGgg L_aL_aL_aL_aL_a L_oL_oL_oL_oL_o (1D_vD_vV_vV_v) (2N_vN_vrr)

Note:

Note

Groups 00000 to 55555 can be repeated as often as necessary.

4.1.1 Iceberg Message Header

Sample iceberg message header:

IBXXN CCCC YYGGgg
PPPP P_tN_rN_rN_rN_r YYMMJJ

This section is mandatory for all iceberg messages.

Table 4.1: Iceberg Message Header

4.1.2 Track Information

Sample track information message:

00000
Q_cL_aL_aL_aL_aL_a L_oL_oL_oL_oL_o ZGGgg 1C_sAAA 2V_IV_I 3RlRlRlR_rR_rR_r 4D_sD_sH_sH_s

This section is mandatory for icebreakers and aircraft. (Note 7, p. 4-13).

Table 4.2: Track Information

4.1.3 Individual Observations

Sample of individual observation message:

11111
(SSSS) (I_dI_dI_dI_d) C_IGGgg L_aL_aL_aL_aL_a L_oL_oL_oL_oL_o 01C_iS_iS_h
(1C_lLEN 2C_lWID 3C_lHEI 4C_lDRA 5C_lDIR 6C_lSPE)

Table 4.3: Individual Observations

4.1.4 Cluster Observations

Sample of cluster observation message:

22222
(SSSS) C_IGGgg L_aL_aL_aL_aL_a L_oL_oL_oL_oL_o N_tN_tDrr nnC_iS_iS_h (nnC_iS_iS_h)

Table 4.4: Cluster Information

4.1.5 Grid Observations

Sample of grid observation message:

33333
C_IGGgg L_aL_aL_aL_aL_a L_oL_oL_oL_oL_o L_aL_aL_aL_aL_a L_oL_oL_oL_oL_o nnnnD ( nnnnD)

Table 4.5: Grid Observations

4.1.6 Zone Observations

Sample of zone observation message:

44444
C_IGGgg L_aL_aL_aL_aL_a L_oL_oL_oL_oL_o (1m_am_am_om_o) 2N_tN_tN_tD nnC_iS_iS_h (nnC_iS_iS_h)

Table 4.6 Zone Observations

4.1.7 Ship Locations

Sample of ship location message:

55555
(SSSS) C_IGGgg L_aL_aL_aL_aL_a L_oL_oL_oL_oL_o (1D_vD_vV_vV_v) (2N_vN_vrr)

Table 4.7 Ship Locations

4.1.8 Plain Language Remarks

REMARKS (Note 15, p. 4-15)

END (*Mandatory end of message)

4.2 Iceberg Coding Tables

Table 4.8: Size of Iceberg (S_i)

Table 4.9: Shape of Iceberg (S_h)

Table 4.10: Concentration of Sea Ice (C_i)

Table 4.11: Quadrant of the Globe (Q_c)

Table 4.12: Distribution of Sea Ice (C_s)

Table 4.13:Confidence Level/Method of Observation (C_l)

Note:

A "Z" found in the Ship Location section of older messages is treated as code 3.

Table 4.14: Platform Type (P_t)

Table 4.15: Iceberg Distribution (D)

Table 4.16: Source of Iceberg Message (N)

4.3 Notes on Iceberg Coding Procedures

1. Nationality of originator of iceberg message is indicated by CN for Canadian and US for American.
2. To facilitate turn-around of iceberg data, messages are designated by source:
   • Aerial reconnaissance by Meteorological Service of Canada and International Ice Patrol
   • Canadian Coast Guard icebreakers
   • Commercial ships, land stations and miscellaneous reports input by Ice Operations Centres
   • Offshore industry
   • Miscellaneous iceberg reports input by the Canadian Ice Service
3. When transmitted from or through a land station, CCCC is the four-letter identifier, but when transmitted directly from an icebreaker or an aircraft, CCCC becomes the four-letter or four-figure identifier of the ship or aircraft.
4. Normally a reconnaissance is conducted from one platform and the PPPP code for the identifier is in brackets e.g., icebreaker Henry Larsen (CGHL), MSC Dash-7 (GCFR) and US Coast Guard C130 (1504). Messages from Ice Operations Centres may be comprised of reports from several commercial ships and PPPP becomes (SHIP) or if the message is an assortment of reports from shore stations PPPP becomes (LAND). Messages from the offshore industry will usually include reports from rigs and supply vessels and PPPP is coded as (RIGG).
5. Consecutive iceberg message numbers shall commence January 1^st each year.
6. Since reconnaissance missions may extend through two days, YYMMJ refers to the date on which the mission began or in the case of a message from industry or Ice Operations Centres the date of the first sighting.
7. A track is made up of one or more legs defined by position, time and parameters. There are as many legs (lines of code) as required to describe all turning points or any change of parameters, e.g., general sea-ice description, aircraft altitude, visibility, radar range and sea state. Although complete detail is required to reproduce a plot as if it was drawn by the observer, complicated tracks should be redrawn to give a simpler track with appropriate visibility and radar ranges to outline the area of coverage. Variable parameters could be averaged to keep the message to a reasonable length. The last track line must only contain the latitude, longitude and time parameters.
8. If a mission starts or ends at a shorebase, the first and last position becomes the international call sign of the shorebase. An aerial mission may start or end at any position. For example, a mission from Iqaluit to observe icebergs in Hudson Strait and then sea ice in Hudson Bay, would end iceberg reporting in western Hudson Strait. In this same example, if the mission re-entered Hudson Strait to continue iceberg reporting, the endpoint of the first iceberg reconnaissance would be joined to this restart point by a straight line with all parameters coded as X's. Track legs over stretches of land may have all parameters coded as X.
9. Each leg start position is, by default, the end position of any previous leg; consequently, the last line of the track is always position and time. For stationary icebreakers, these two positions are the same.
10. For icebergs, visibility or radar limits are defined by the distance from the ship or aircraft that the observer feels confident that he/she can see or get a radar return for all small icebergs. This does not preclude the observation and reporting of icebergs beyond these limits. the radar visibility must have a minimum of 2 digits and a maximum of 3 digits on either side.
11. Experienced Ice Services Specialist may estimate the wave or swell group visually or by radar from an aircraft or report XXXX for "undetermined". Icebreakers should report the group.
12. The individual-position method of iceberg and target reporting should be used in areas near the iceberg limit, areas of offshore drilling activity, the approaches to the Strait of Belle Isle and in all other areas where icebergs are evenly distributed and their numbers permit. When numbers increase or when icebergs are concentrated in small areas, a combination of cluster and individual methods can be used. When numbers become unmanageable, zones and grids should be incorporated.
13. Messages from the offshore industry and from Ice Operations Centres consist of iceberg reports from individual sources such as commercial ships, rig supply vessels, land stations, etc. If the iceberg message contains only one individual source, the message is coded with PPPP in the second line of the header information and is coded as the first four letters (or figures) of the call sign of the single source. However, if the iceberg message contains iceberg reports from more than one source, the optional group SSSS is used to indicate the call signs of the individual sources.
14. The offshore industry usually tracks icebergs through their area of interest. Icebergs entering the area are assigned a consecutive number which is maintained until the iceberg exits from the area. The optional group IdIdIdIdI is used by the offshore industry to code the assigned number of the iceberg and to indicate if the iceberg is freely drifting (D), grounded (G) or is under tow (T).
15. The degree of confidence in an iceberg's observed position and related parameters is expressed by C_I. The highest confidence (Code 1) is a radar position with visual confirmation. There should be an attempt to consolidate visual and radar data to produce high confidence levels. Radar-only targets (Code 2) will not appear in areas visually searched, unless there is some doubt about the visual capability which should be expressed in the REMARKS section.
16. The time of observation is the time at which an individual iceberg, the centre of a cluster, the southwest corner of a zone or the start point of a grid becomes abeam of the track. Times may be rounded off to the nearest 15 minutes but they must be within the time frame of the track leg from which the observations were made.
17. The concentration of sea ice is a factor which affects iceberg drift and which provides the user with some degree of confidence in iceberg detection, especially if the detection is made by radar. There shall be an attempt to describe the ice cover to the nearest tenth immediately adjacent to the iceberg. However, when the concentration varies from side to side, the recorded concentration will be an average of the conditions around the iceberg. Open water areas or trails caused by the iceberg will be disregarded.
18. Sizes refer to the portion of the iceberg above water. If height and length of a berg in metres (m) fall into a different size classification, use the larger size. Dimensions (in kilometres) of a tabular berg or ice island may be indicated beneath the symbol. Iceberg size and shape parameters are important in the process of re-identification of icebergs and as inputs to iceberg deterioration and drift models. These parameters shall be reported along the limit of icebergs, in areas of offshore drilling activity, in the approaches to the Strait of Belle Isle and in all areas where the work load permits. When icebergs are more numerous, shape parameters should be simply tabular or non-tabular. When icebergs become too numerous, use code 7 for unspecified size and code 0 for unspecified shape. X's will only be used for radar information.
19. The optional groups (1C_lLEN 2C_lWID 3C_lHEI 4C_lDRA 5C_lDIR 6C_lSPE) shall be used when any of the length, width, height, draft, direction and speed iceberg parameters are available. The confidence level in this group shall only be measured (Code 4) or (Code 5).
20. Accurate determination of the positions and radii of clusters is essential so that the circles do not overlap other clusters, zones or grids, overlap land or extend beyond the applicable radar or visual limit. Normally observations by individual position will not be included inside a cluster. However a visually confirmed iceberg through a hole in the clouds could be included in a radar cluster and in this case the total number of icebergs reported in the cluster would not include the individual iceberg.
21. If there are no bergy bits or growlers present, nn equals N_tN_t for clusters or N_tN_tN_t for zones. S_i is coded as 7 for not specified and S_h is coded as 0 for not specified. However, when the workload permits, the code allows specifying the numbers of different sizes and shapes within the grid or zone. For example, in a cluster free of sea ice which has 1 very large tabular iceberg, 3 medium icebergs, 5 small icebergs and 2 bergy bits which are all evenly distributed within a radius of 5 nautical miles,N_tN_tD_rr nnC_iS_iS_hnnC_i S_iS_hnnC_iS_iS_hnnC_iS_iS _hwould be coded as: 09110 01061 03040 05030 02020.
22. Grids are defined by the confidence level (whether radar and visual, radar only or visual only), by two positions along the track, by the visibility or radar limits as coded in the track part of the message and by the iceberg distribution (left of track, right of track or both sides of track). A visual and radar or a visual-only grid extends from the track line to the visibility limit. A radar-only rid extends from the track to the radar limit or if there is a visible limit, the grid extends from the visibility limit to the radar limit. Two lines of code are required to encode both visual and radar grids with the same endpoints. Clusters will not be reported inside grids and normally individual icebergs should be excluded. However, individual icebergs which are considered significant because of ize, shape or other parameters which can assist in reidentification may be positioned inside of the grid. The time assigned to the grid associates it with the correct visibility and/or radar limits coded in the track leg, so it is essential that the time refers to the right leg. Grids will not extend beyond one track leg.
23. An accurate count of iceberg numbers in grids, clusters and zones is desired. However, when numbers are too large, report an estimate and explain in the REMARKS section.
24. Zones are areas usually one degree latitude by one degree longitude defined by the latitude and longitude of the southwest corner. The optional group 1m_am_am_om_o permits the use of nonstandard zones. Zones should not overlap other zones, grids or clusters, or extend beyond the appropriate visibility or radar limit. As with clusters and grids, individual icebergs should not normally appear in zones.
25. Factors, such as turbulence, drift angle, precipitation and sea state, that can effect radar; and variable visibilities or breaks in the undercast that effect visual capabilities shall be included.
26. The platform identifier group PPPP, found in the Iceberg Messae Header, and the optional ship identifier group (SSSS), coded in the observation reports can be extended to contain up to 7 alphanumeric characters.

4.4 Examples of Coded Iceberg Reports