ATLANTARC_SEA_ICE_readme TITLE: Historical Sea Ice Time Series from the Atlantic Arctic AUTHOR: Martin Miles, Compiler (PI) Environmental Systems Analysis Research Center 4450 Arapahoe Ave. Ste. 100, Boulder, CO 80303 Telephone: 303 415 2515; Fax: 303 415 2515 WWW: www.esarc-colorado.org E-mail: martin.miles@esarc-colorado.org FUNDING SOURCE AND GRANT NUMBER: National Science Foundation, Arctic System Science program, Award # 0531286 DATA SET OVERVIEW: The 'Historical Sea Ice Time Series from the Atlantic Arctic' data collection is a compilation of existing century-scale time series derived from historical observations and sea ice charts from a range of sources. The purpose of the dataset is to provide a convenient compilation and consistent description of these data that are published though scattered. Provided here are various indices of sea-ice conditions, ranging from estimated sea-ice extent, sea-ice edge, sea-ice export and sea-ice incidence (duration). The original time series were constructed by individual researchers using various sources ranging from historical ice charts to annals and other descriptive information. Acknowledgement is due to these researchers (see references below) and to the sea-ice observers through the centuries. Spatial and temporal coverage varies. Spatially, the data span the Atlantic Arctic from Newfoundland to the Barents and Baltic Seas. The representativeness of each series is typically sub-regional (10s of km) to regional (100s of km). Temporally, the time series are range from approximately one to three centuries. There are few years with missing values, usually in the early part of the series. There is generally one value per year; however, the effective temporal resolution is sub-annual, typically representing a seasonal indicator. DATA COLLECTION and PROCESSING: Data set is a collection/compilation of existing published time series. Processing performed here is limited to consistent formatting, checking for outliers and re-coding missing data. values. DATA FORMAT: Data file is column-delimited ASCII text. Column 1 is Year and other columns are sea-ice time series arranged from west to east. Missing data = -999.9. The following is a list of column definitions. - Column Year: Year. For seasonal indices spanning the end of a year, year is the end of winter, e.g., winter 1968/69 is 1969. - Column NFLw: Newfoundland winter sea-ice extent, expressed as 10^3 km^2 (Hill, 1999). - Column SWGr: Northward extension of arctic sea ice past Cape Farewell, expressed as 10s of km, (Fabricius et al., 1995) - Column FSexp: Fram Strait annual sea-ice export reconstructed from 'SWGr', expressed as km^3 (Schmith and Hansen, 2003). - Column Icel-m: Icelandic sea-ice incidence index, modern record, expressed as weeks per year (Wallevík and Sigurjónsson, 1998). - Column GS04: Greenland Sea ice-edge anomaly in April, expressed as km (Divine and Dick, 2006). - Column GS06: Greenland Sea ice-edge anomaly in June, expressed as km (Divine and Dick, 2006). - Column GS08: Greenland Sea ice-edge anomaly in August, expressed as km (Divine and Dick, 2006). - Column WNS: Western Nordic Seas ice extent in August, expressed as 10^3 km^2 (Vinje, 2001). - Column WBS04: Western Barents Sea ice-edge anomaly in April, expressed as km (Divine and Dick, 2006). - Column WBS06: Western Barents Sea ice-edge anomaly in June, expressed as km (Divine and Dick, 2006). - Column WBS08: Western Barents Sea ice-edge anomaly in August, expressed as km (Divine and Dick, 2006). - Column WNS: Western Nordic Seas ice extent in August, expressed as 10^3 km^2. - Column ENS: Eastern Nordic Seas ice extent in August, expressed as 10^3 km^2 (Vinje, 2001). - Column Baltic-m: Baltic Sea maximum ice extent, expressed as 10^3 km^2 (Seina and Palosuo, 2006). DATA REMARKS: Units vary; standardization recommended for between-series comparison. Details of source material, methods and quality assessment are available for each series in the reference provided here. REFERENCES: Divine, D. V. and C. Dick, 2006: Historical variability of sea ice edge position in the Nordic Seas.J. Geophys. Res., 111, C01001. doi:10.1029/2004JC002851. Fabricius, J., K. Frydendahl and P. Frich, 1995: Polar sea ice off west Greenland - a review. Proc. 14th Int. Offshore Mechanics and Arctic Engineering Conf., Copenhagen, Denmark, American Society of Mechanical Engineers, 265-272. Hill, B. T., 1999: Historical record of sea ice and iceberg distribution around Newfoundland and Labrador, 1810-1958 WCRP No. 108 or WMO/TD No. 949, April/99, ACSYS, Proc. of the Workshop on Sea Ice Charts of the Arctic, Seattle, WA August 5-7, 1998. Schmith, T. and C. Hansen, 2003: Fram Strait ice export during the nineteenth and twentieth centuries reconstructed from a multiyear ice from southwestern Greenland. J. Climate, 16, 2782-2791. Seina, A. and E. Palosuo, 2006: The classification of the maximum annual extent of ice cover in the Baltic Sea 1720-1995. Meri Rep. Ser. Finn. Inst. Mar. Res., 27, Finn. Inst. Mar. Res., Helsinki. Vinje, T., 2001: Anomalies and trends of sea ice extent and atmospheric circulation in the Nordic Seas during the period 1864-1998, J. Clim., 14, 255-267. Wallevík, J. and H. Sigurjónsson, 1998: The Koch index. formulation, corrections and extensions. Vedurstofa Íslands Report, VÍ-G98035-ÚR28, Reykjavik, Iceland.