Alaska Sea Ice Program(ASIP) Ice Chart Web Service is derived from the Alaska Sea Ice Analysis GIS Shapefile and The Alaska Sea Ice Forecast GIS Shapefile. The web service has three layers: Daily Total Concentration of Ice and Snow; Daily Stage of Development(thickness) of ice and snow; and ASIP Forecast.

The Alaska Sea Ice Analysis GIS Shapefile contains SIGRID-3 information on ice conditions that are separated into various fields including total ice concentration, ice types and their respective partial concentrations and other sea ice characteristics. This analysis is updated daily by 0030 UTC, and available on the NWS Alaska Sea Ice Program (ASIP) Graphical webpage at https://weather.gov/afc/ice. The Alaska Sea Ice Analysis GIS Shapefile is accessible for download at https://www.weather.gov/source/afc/icedata/full_latest.zip.

The SIGRID-3 vector archive format is one of the World Meteorological Organization (WMO) standards for archiving digital ice charts. The NWS Alaska Sea Ice Program (ASIP) creates SIGRID-3 ice charts on a regular basis for Alaska waters including the Beaufort Sea, Chukchi Sea, Bering Sea, and Cook Inlet. These SIGRID-3 files have two main components: the shapefile containing the ice analysis information (ice polygons and related attributes) and the metadata describing the ice analysis data under the SIGRID-3 format. The Sea Ice Analysis represents ice conditions valid at approximately 0030 UTC but is analyzed from imagery over the preceding 24hrs. Imagery utilized includes synthetic aperture radar (SAR), polar orbiting imagery such as VIIRS, other optical or infrared sensors prioritized by recency and image quality, and application of an understanding of conditions gained from local observations and forecast weather conditions.

The Alaska Sea Ice Forecast GIS Shapefile contains information on forecast ice conditions that are separated into various fields including marginal ice zone, pack ice, shorefast ice, and sea ice free waters. This forecast is updated by 0030 UTC on Mondays, Wednesdays and Fridays. It is also available at https://weather.gov/afc/ice. The Alaska Sea Ice Forecast GIS Shapefile is updated Monday, Wednesday, and Fridays after 3:30pm AKST and is accessible for download at https://www.weather.gov/source/afc/icedata/forecast_latest.zip.

The NWS Alaska Sea Ice Program (ASIP) creates sea ice forecast charts each Monday, Wednesday, and Friday for Alaska waters including the Beaufort Sea, Chukchi Sea, Bering Sea, and Cook Inlet. These files have two main components: the shapefile containing the ice forecast information (ice polygons and related attributes) and the metadata describing the ice analysis data. The Sea Ice Forecast is valid 5 days after issuance (i.e. a forecast produced on Monday is valid on the following Saturday). Information utilized includes weather models, sea ice models, forecast ocean currents, and analyst experience.

Questions/Concerns about the service, please contact the DISS-GIS team.

For questions about the underlying data or other ice datasets, please email the ASIP sea ice analysts at nws.ar.ice@noaa.gov.

Time Information: This service is not time enabled.