The role of science is to assess evidence and show which of several possible answers has the most support. Remaining uncertainties indicate what to investigate next.
We all make choices that are based on incomplete information. It is helpful to know about uncertainties up front so that we can make informed decisions.
Key findings from a 2011 report on the need for spatial tools for Arctic mapping and planning indicate that:
Marine resource management decisions are often made through processes that are not based explicitly on resource data … important weaknesses in current decision-making processes involve two issues that spatial tools can help address: public participation and the availability of data and information.
The most pressing management decisions revolve around climate change and the associated changes in environmental conditions coupled with increasing industrial development and consequent human uses of the ocean and near shore environments.
For the first time, you can simultaneously view multiple sources of historical sea ice data from the oceans surrounding northern Alaska. Choose a region and time of interest and inspect a map of data collected between the mid-1800s and today, to discover how ice extent and concentration have changed over time.
If you are a resident of a coastal community, someone who hunts or fishes in a marine environment, a member of the shipping or oil + gas industries, in the US Coast guard, a scientist, or otherwise interested in Arctic sea ice data and climate change, this atlas is for you.
These data show “snapshots” in time, as well as historical trends in arctic sea ice cover and extent. They are not projections or predictions of future conditions. The atlas is not designed for forecasting or prediction, but can provide useful historical context for future planning efforts.
Data collection challenges. Collecting sea ice data has always been difficult and dangerous work. Historic interpretations of ice concentration differed from modern protocols. A wide variety of instrument calibrations and sensors (human observation, radar, satellites) has been used over time. All add up to data inconsistencies.
Data compilation choices. Compiling data involves choices: Which hard copy maps to digitize? How do we interpret this handwriting? How do we fill gaps in the data record? Which time scale is best to use? These choices lead to uncertainty.
Analog filling of spatial and temporal gaps: Spatial and temporal gaps in a given grid filled with best analog representations of the given month.
Arctic and Antarctic Research Institute (AARI) Located in St. Petersburg, Russia, AARI produces sea ice charts for safety of navigation in the Eurasian Arctic and other operational and scientific purposes. Chart coverage focuses on the Northern Sea Route, although later charts extend into the central Arctic. Charts contain several categories of ice concentration.
Arctic Climate System Study (ACSYS) An activity of the World Climate Research Program. Includes digitized ice edge positions for the north Atlantic. ACSYS Ice edge information is irregular in time and space, and is most frequent in the 20th century. When available, ice edge data are provided monthly. The ACSYS study has expanded into the Climate and Cryosphere Project. Visit the ACSYS/CliC Historical Ice Chart Archive to access all data from this work.
Danish Meteorological Institute (DMI) These charts provide observed and inferred sea ice extent for each summer month from 1893–1956. Additionally, Kelly et al. have digitized summer (May-Sept) ice edge information from DMI's monthly maps.
Japan Meteorological Agency Monitors sea ice in the Sea of Okhotsk from November to July. Results of monitoring are published for public use.
Kelly ice extent grids Digitized ice edge information from monthly maps of Danish Meteorological Institute, May-Sept only. Kelly digitized only the inferred ice edge and only to a spatial resolution of about 100 km, depending on the distance of the ice boundary to the pole. He chose not to improve the resolution because of the low accuracy of the inferred ice edge itself. The eventual plan was for this digitized data to be incorporated on a one-degree grid into larger sea ice data products as an ice/no ice indicator.
Naval Oceanographic Office (NAVOCEANO) Oversees the Naval Ice Center (NAVICE), which provides worldwide operational ice analyses for the US military and government agencies as well as allied nations. Sea ice maps for the Alaskan and Greenland sectors were compiled into yearbooks for the period 1953–1971. Hard copies of yearbooks are held by the National Snow and Ice Data Center (NSIDC). In 1972, ice charting was transitioned to the predecessor of the National Ice Center.
Navy-NOAA Joint Ice Center Climatology The National Ice Center began in 1976 as the Joint Ice Center in 1976, comprised of personnel from NOAA and the US Navy. In 1995, the Joint Ice Center became the National Ice Center as it expanded to include the US Coast Guard. Coast Guard aircraft, icebreakers, and Marine Safety Offices contribute valuable platforms for onsite aerial and ship observations, as well as accurate and timely ship and station reports. Ice charts dating back to 1972 are from predecessor organization. Hard-copy (paper) charts produced by analysts are subsequently scanned and digitized. Ice charts are based mainly on satellite imagery, supplemented by aircraft, ship and shore reports.
NSIDC Bill Dehn Data Collection Scanned versions of almost 7,000 ice charts donated to the National Snow and Ice Data Center (NSIDC) by the estate of Bill Dehn are available through a searchable interface. A subset of the charts have been digitized by the Alaska Center for Climate Assessment and Policy (ACCAP).
NSIDC SMMR/SSMI/AMSR microwavew sensor data Three separate microwave sensors. AMSR-E is the latest sensor, improving upon past microwave radiometers SSM/I and SMMR. The spatial resolution of AMSR-E data doubles that of Scanning Multichannel Microwave Radiometer (SMMR) and Special Sensor Microwave/Imager (SSM/I) data. Also, AMSR-E combines into one sensor all the channels that SMMR and SSM/I had individually.
Walsh and Johnson/Navy-NOAA Joint Ice Center Early version of pan-Arctic digital database of Arctic sea ice concentrations. Grids cover the pre-satellite (passive microwave) period and are synthesized from various sources. Resolution is 60 nautical miles in space and monthly in time. Described in: Walsh and Johnson, 1979, J. Phys. Oceanography, 9, 58–591.
Whaling ship logbook data Daily observations taken from logbooks and journals of whaling vessels cruising in the Bering and Chukchi seas to investigate seaice conditions in this region of the Arctic between 1850 and 1914. Extracted and digitized daily data on the presence or absence of sea ice from logbook records of annual cruises in an unbroken record from 1850 to 1914, though there were very few cruises (hence inadequate data) from 1911 to 1914. Data include more than 52,000 daily observations in an unbroken 65 year record from 516 cruises. These represent 19% of the total 2,712 cruises. Similar findings are discussed by Eicken et al. in this paper.