Arctic Sea Ice Seasonal Change and Melt/Freeze Climate Indicators from Satellite Data, Version 1

The product contains melt-season indicators that can be used to delineate various stages in the summer melt and freeze-up period of sea ice. The data were primarily derived using Sea Ice Concentration (SIC) observations from the NOAA/NSIDC Climate Data Record of Passive Microwave Sea Ice Concentration and brightness temperature observations from the DMSP SSM/I-SSMIS Daily Polar Gridded Brightness Temperatures; both input data sets are archived at NSIDC. The main parameters for this data set include the dates of melt onset, early melt onset, and continuous melt onset; dates of early and continuous freeze onset; day of opening (last day SIC is above 80%); day of retreat (last day SIC drops below 15%); day of advance (first day SIC increases above 15%); day of closing (first day SIC increases above 80%); total outer ice-free period; total inner ice-free period; seasonal loss-of-ice period; seasonal gain-of-ice period; and the seasonal ice zone. These data are available for 1979 through 2017. They are gridded on the NSIDC northern hemisphere polar stereographic grid at 25 km.本数据集内置融季指标，可用于划分海冰夏季融化与封冻期的各个阶段。本数据集主要依托美国国家海洋和大气管理局/国家冰雪数据中心（NOAA/NSIDC）被动微波海冰密集度（Sea Ice Concentration, SIC）气候数据记录中的观测数据，以及国防气象卫星计划专用多传感器微波成像仪/专用微波扫描辐射计成像仪（DMSP SSM/I-SSMIS）的每日极区网格化亮温观测数据生成；上述两类输入数据集均归档于国家冰雪数据中心（NSIDC）。本数据集的核心参数包括：融化起始日期、早期融化起始日期与持续融化起始日期；早期封冻起始日期与持续封冻起始日期；冰间开阔日（海冰密集度维持80%以上的最后一日）、冰消退日（海冰密集度跌破15%的最后一日）、冰推进日（海冰密集度首次升至15%以上的首日）、冰封冻日（海冰密集度首次升至80%以上的首日）；总外部无冰期、总内部无冰期、季节性失冰期、季节性得冰期，以及季节性海冰带。 本数据集的时间覆盖范围为1979年至2017年，数据采用国家冰雪数据中心（NSIDC）北半球极地方位投影网格，空间分辨率为25千米。