Keywords
Theme:
sea ice, ice type, ice age, ice concentration, form of ice, floe size
Place:
Baffin Bay, Baltic Sea, Barents Sea NE, Barents Sea NW, Barents Sea South, Beaufort Sea, Canadian Arctic East, Canadian Arctic West, Chukchi Sea, Cook Inlet, Davis Strait, East Bering Sea, East Siberian Sea, Foxe Basin, Grand Banks, Greenland Central, Greenland North, Greenland South, Greenland West, Gulf of St Lawrence, High Arctic East, High Arctic West 1, High Arctic West 2, Hudson Bay, Kamchatka, Kara Sea North, Kara Sea South, Labrador Sea, Laptev Sea, Sea of Japan, Sea of Japan South, Sea of Okhotsk East, Sea of Okhotsk South, Sea of Okhotsk Southeast, Sea of Okhotsk West, Skagerrak, West Bering Sea, White Sea, Yellow Sea
Description
Abstract
The SIGRID-3 vector archive format is one of the World Meteorological Organization (WMO) standards for archiving digital ice charts in the Global Digital Sea Ice Data Bank (GDSIDB). The WMO ice chart archiving formats are the Sea Ice Grid (SIGRID) format developed in 1981 and formalized in 1989 and its successor SIGRID-2. The National Ice Center digital Ice Analysis charts (Hemispheric, Regional and Daily are encoded in SIGRID-3 and have two main components: the shapefile containing the Ice Analysis ice information (ice polygons and related attributes) and the metadata describing the Ice Analysis data under the SIGRID-3 format.
The National Ice Center legacy ice data set contains hemispheric spatial data files from 1972 through 2004 inclusive. Regional Spatial data files of the traditional "seas"(ex Beaufort Sea) have been available since 1997. Legacy data are available in various formats from the National Snow and Ice Data Center in Boulder, Colorado ( http://nsidc.org/ ). Legacy Great Lakes charts are available from the Great Lakes Environmental Research Laboratory in Ann Arbor, Michigan ( http://www.glerl.noaa.gov/ ).
Currently (October, 2006), spatial data files are available for each hemisphere, and for each sub-regional area, of which there are approximately 62. The ice analyses for each sea or sub-sea are also available in a pdf format. They represent the ice conditions for the week in which they are published. Data for the analyses can go back 96 hours from when they are completed. They are dated with the week they are published. They are based on an analysis and integration of all available data on ice conditions, including weather and oceanographic information, visual observations from shore, ship and aircraft, airborne radar, satellite imagery and climatological information. The Regional Ice Analyses describe areas of differing ice conditions using the WMO ice observing standards, and indicate where significant changes in the amount, stage of development and form of the predominant ice types have occurred. The Regional Ice Analyses for all of the Northern and Southern Hemisphere Seas are produced every other week. The analyses for the Bering, Chukchi, Beaufort, Arctic Basin (High Arctic), Northern East Greenland, Barents, Kara and White Seas and the Cook Inlet are produced at least weekly. The Ross Sea is produced weekly during Austral Summer navigation season. The Chesapeake and Delaware Bay areas are produced weekly when there is ice. The analyses for the Great Lakes (when there is ice and in collaboration with the Canadian Ice Service), the Bering Sea, the Cook Inlet and the Chukchi and Beaufort Seas are produced twice per week when there is an ice edge present. The National Ice Center also produced daily ice edges in text format for both the Northern and Southern Hemispheres.
Purpose
The SIGRID-3 Regional Ice Analysis products are mainly used for climate analysis, climate change studies and as input to the Global Digital Sea Ice Data Bank (GDSIDB). They can also provide ice information to marine community to enhance the safety and the efficiency of marine operations in ice-encumbered waters.
_________________
Status of the data
Complete
Data update frequency:
No changes or additions are made to the data set after the data set is distributed. If modifications are made to the data set, a new version is released along with its metadata.
Time period for which the data is relevant
Date and time:
11/19/2007 through 11/23/2007
Description:
same as Publication Date
Publication Information
Who created the data: National Ice Center (NIC)
Date and time:
11/21/2007
_________________
Data storage and access information
Type of data: vector digital data
Data processing environment: Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.2.2.1350
Accessing the data
Size of the data: 9.197 MB
Data transfer size: 9.197 MB
Constraints on accessing and using the data
Access constraints:
none
Use constraints:
With accreditation from the National Ice Center
Details about this document
Contents last updated: 20071121
at time 14261600
Who completed this document
cschinkel
National Ice Center (NIC)
mailing and physical address:
(301) 394-3100 (voice)
(301) 394-3200 (fax)
liaison@natice.noaa.gov
Standards used to create this document
Standard name: FGDC Content Standards for Digital Geospatial Metadata
Standard version: FGDC-STD-001-1998
Time convention used in this document: local time
Metadata profiles defining additonal information
ESRI Metadata Profile: http://www.esri.com/metadata/esriprof80.html
Horizontal coordinate system
Projected coordinate system name: WGS_1984_Stereographic_North_Pole
Geographic coordinate system name: GCS_WGS_1984
Details
Map Projection Name: Stereographic_North_Pole
Standard Parallel: 60.000000
Longitude of Central Meridian: 180.000000
False Easting: 0.000000
False Northing: 0.000000
Planar Coordinate Information
Planar Distance Units: meters
Coordinate Encoding Method: coordinate pair
Coordinate Representation
Abscissa Resolution: 0.000000
Ordinate Resolution: 0.000000
Geodetic Model
Horizontal Datum Name: D_WGS_1984
Ellipsoid Name: WGS_1984
Semi-major Axis: 6378137.000000
Denominator of Flattening Ratio: 298.257224
_________________
Bounding coordinates
Horizontal
In decimal degrees
West:
-180.000000
East:
180.000000
North:
90.000000
South:
27.980146
In projected or local coordinates
Left: -5482165.945581
Right: 4582470.856464
Top: 4339885.617508
Bottom: -4594776.026763
_________________
Lineage
FGDC lineage
Process step 1
Process description: Since 1968, Regional Ice Analyses have been compiled from numerous data sources generally acquired plus or minus three days of its publication date. Over the years, data sources have included a wide variety of satellite imagery, aerial reconnaissance and ship borne reports. Each data source and its availability over the years is described in their respective source information. The Regional Ice Analyses are presently being generated using in house software (ISIS system: ERDAS and ARC/Info).
Process date: The Regional Ice Analyses for the Northern Canadian Waters (Western Arctic, Eastern Arctic and Hudson Bay) are produced on a weekly basis during the summer season and since 1982 on a monthly basis for the winter season. The Regional Ice Analyses for the Southern Canadian Waters (East Coast and Great Lakes) are produced on a weekly basis during the winter season only.
Sources
Source 1:
RADARSAT Imagery - 28.21% of total
Media: electronic (Satellite)
Currentness of this source
Beginning date and time:
19960313
Ending date and time:
still active
Source 2:
NOAA Imagery - 0% of total
Media: hardcopy and electronic (Satellite)
Currentness of this source
Beginning date and time:
19701211
Ending date and time:
still active
Source 3:
Advanced Very High Resolution Radiometer - 0.03% of total
Media: electronic (Satellite)
Currentness of this source
Beginning date and time:
19980515
Ending date and time:
still active
Source 4:
OLS Imagery - 14.04% of total
Media: electronic (Satellite)
Currentness of this source
Beginning date and time:
19990521
Ending date and time:
still active
Source 5:
QuikScat Imagery - 8.39% of total
Media: electronic (Satellite)
Currentness of this source
Beginning date and time:
20011101
Ending date and time:
still active
Source 6:
ERS Imagery - 0% of total
Media: electronic (Satellite)
Currentness of this source
Beginning date and time:
19921218
Ending date and time:
20030605
Source 7:
ENVISAT Imagery - 14.26% of total
Media: electronic (Satellite)
Currentness of this source
Beginning date and time:
20031009
Ending date and time:
still active
Source 8:
MODIS - 9.26% of total
Media: electronic (Satellite)
Currentness of this source
Beginning date and time:
20041201
Ending date and time:
still active
Source 9:
SAR Imagery - 0% of total
Media: electronic (Aircraft)
Currentness of this source
Beginning date and time:
19900101
Ending date and time:
19950331
Source 10:
SLAR Imagery - 0% of total
Media: acetate and electronic (Aircraft)
Currentness of this source
Beginning date and time:
19780213
Ending date and time:
still active
Source 11:
Observed Charts - 0% of total
Media: paper, electronic (Aircraft / Helicopter)
Currentness of this source
Beginning date and time:
19570614
Ending date and time:
still active
Source 12:
Image Analysis Charts - 0% of total
Media: paper and electronic (Satellite)
Currentness of this source
Beginning date and time:
19900118
Ending date and time:
still active
Source 13:
Daily Ice Analysis Charts - 0% of total
Media: paper and electronic
Currentness of this source
Beginning date and time:
19590216
Ending date and time:
still active
Source 14:
Regional Ice Analysis Charts - 0% of total
Media: paper and electronic
Currentness of this source
Beginning date and time:
19680625
Ending date and time:
still active
Source 15:
Estimate - 25.82% of total
Media: electronic (Satellite)
Currentness of this source
Beginning date and time:
11/19/2007
Ending date and time:
11/23/2007
_________________
Spatial data description
Vector data information
ESRI description
ARCTIC071119
ESRI feature type: Simple
Geometry type: Polygon
Topology: FALSE
Feature count: 934
Spatial Index: TRUE
Linear referencing: FALSE
SDTS description
Feature class: SDTS feature type, feature count
ARCTIC071119:
G-polygon, 934
Details for Regional Ice Analyses in SIGRID-3 format
Type of object: Feature Class
Number of records: 934
Description
The SIGRID-3 vector archive format is one of the World Meteorological Organization (WMO) standards for archiving digital ice charts in the Global Digital Sea Ice Data Bank (GDSIDB). The WMO ice chart archiving formats are the Sea Ice Grid (SIGRID) format developed in 1981 and formalized in 1989 and its successor SIGRID-2. A Regional Ice Analysis encoded in SIGRID-3 has two main components: the shapefile containing the Regional Ice Analysis ice information (ice polygons and related attributes) and the metadata describing the Regional Ice Analyses data under the SIGRID-3 format. A shapefile consists of three core files (but may include several optional files). Each file in the set shares the shapefile name with a different extension. The main file (*.shp) stores shape geometry and must always have an index file (*.shx). A database file (*.dbf) stores all the attributes of the shapes in the main file. SIGRID-3 uses the widely accepted, public domain eXtensible Markup Language (XML) for metadata (information on the Regional Ice Analysis and how it was generated). A file in XML stores the metadata that pertains to each Regional Ice Analysis. Metadata includes projection, location, keywords, and contact information. A file in XML can be read using a web browser, and it is easy to make it available for searches via the Internet. To archive a Regional Ice Analysis in SIGRID-3 (.tar), four files are required: three for the Regional Ice Analysis in shapefile format (.shp,.shx,.dbf) and one for the metadata (xml). The database file consists of a set of mandatory and optional fields which are described in the Entity Type Definition Source and are listed below.
Source: As per SIGRID standards: undetermined or unknown applicable fields are reported as "99", empty applicable fields are reported as "-9" and empty or unknown non applicable fields are reported as null. Two new attributes (COVSHP_ , COVSHP_ID) are added to the list of SIGRID-3 attributes during the automatic conversion of the Regional Ice Analysis from coverage to shapefile. They are both sequential unique whole numbers that are automatically generated by the ESRI conversion tool (as is the FID Label). For more information, please refer to the SIGRID-3: A Vector Archive Format for Sea Ice Charts Developed by the International Ice Charting Working Groups Ad Hoc Format Team for the WMO "Global Digital Sea Ice Data Bank" project (WMO/TD-No. 1214, 2004)
Attributes
FID
Definition: Internal feature number.
Definition Source: ESRI
Shape
Definition: Feature geometry.
Definition Source: ESRI
CT
Data type: String
Width: 45
Definition: Total concentration of all ice in the area
Definition Source: WMO JCOMM ETSI
CA
Data type: String
Width: 2
Definition: Partial concentration of thickest ice
Definition Source: WMO JCOMM ETSI
SA
Data type: String
Width: 2
Definition: Stage of development of thickest ice
Definition Source: WMO JCOMM ETSI
SC
Data type: String
Width: 2
Definition: Stage of development of third thickest ice
Definition Source: WMO JCOMM ETSI
FC
Data type: String
Width: 2
Definition: Form of ice corresponding to SC
Definition Source: WMO JCOMM ETSI
FA
Data type: String
Width: 2
Definition: Form of ice corresponding to SA
Definition Source: WMO JCOMM ETSI
CB
Data type: String
Width: 2
Definition: Partial concentration of second thickest ice
Definition Source: WMO JCOMM ETSI
SB
Data type: String
Width: 2
Definition: Stage of development of second thickest ice
Definition Source: WMO JCOMM ETSI
POLY_TYPE
Data type: String
Width: 2
Definition: Surface Type
Definition Source: WMO JCOMM ETSI
ICECODE
Alias: ICECODE
Data type: String
Width: 2
CC
Data type: String
Width: 2
Definition: Partial concentration of third thickest ice
Definition Source: WMO JCOMM ETSI
FB
Data type: String
Width: 2
Definition: Form of ice corresponding to SB
Definition Source: WMO JCOMM ETSI
SO
Alias: SO
Data type: String
Width: 2
SD
Alias: SD
Data type: String
Width: 2
FP
Alias: FP
Data type: String
Width: 2
FS
Alias: FS
Data type: String
Width: 2