AARI 10-Day Arctic Ocean EASE-Grid Sea Ice Observations, Version 1

NOTE: This data set has been replaced by the Sea Ice Charts of the
Russian Arctic in Gridded Format, 1933-2006 data set.

These gridded ice charts represent a reformatting of information contained in another data set, the Russian Arctic and Antarctic Research Institute's (AARI) 10 Day Digital Arctic Sea Ice Charts. AARI digitized Arctic sea iceconcentration and stage of development charts as part of an international data exchange program. The AARI source charts, similar to operational charts distributed by the National Ice Center describing ice type and constitution, were developed from aircraft and satellite observations for shipping purposes, and provide extremely detailed information.Such data are particularly valued in process studies tracking the growth and recession of polynyas, or for looking at the preponderance of ice at certain stages of development in a particular area. NSIDC does not maintain the operational charts, but archives the AARI digitized version. However, the Arctic and Antarctic Research Institute (AARI) 10 Day Digital Arctic Sea Ice Charts were encoded in SIGRID (Sea Ice Grid) format, which assigns numerical values to ice parameters and records them at specific lat/lon grid points. But due to the difficulties of visualizing, extracting and working with data in SIGRID, NSIDC is now providing
AARI data in NSIDC's Equal Area SSM/I Earth Grid.

The EASE-Grid format makes it especially easy to compare observed ice concentrations or ice types with the same parameters derived from satellite data (such as ice concentrations from passive microwave sensors).

AARI sea ice data in the EASE-Grid projection are gridded at a 12.5 km resolution, for both Western (24W to 110E) and Eastern (105E to 130W) sectors . Data extend from 1953 through 1990. Postscript (.ps) files depicting coverage per year are also provided with the data.

注意：本数据集已由《1933-2006年格点化俄罗斯北极海冰图》数据集替代。

这些格点化海冰图是对另一数据集——俄罗斯北极与南极研究所（Arctic and Antarctic Research Institute，AARI）的《10日数字化北极海冰图》中所含信息的重新格式化处理。作为国际数据交换计划的一部分，AARI对北极海冰密集度与冰况发展阶段图进行了数字化。AARI的源图与国家冰中心（National Ice Center）发布的业务化海冰图类似，后者用于描述冰型与冰组成，基于航空与卫星观测数据制作，服务于航运保障需求，且包含极为详尽的海冰信息。

此类数据在追踪冰间湖（polynyas）的消长过程，或是分析特定区域内特定发展阶段海冰的占比时，具有极高的研究价值。美国国家冰雪数据中心（National Snow and Ice Data Center，NSIDC）并不维护原始业务化海冰图，仅存档AARI的数字化版本。不过，AARI的《10日数字化北极海冰图》采用SIGRID（海冰网格）格式进行编码，该格式为海冰参数赋予数值，并在特定经纬度网格点上记录这些参数。但由于SIGRID格式的数据在可视化、提取与处理方面存在诸多困难，NSIDC现已将AARI的数据转换为NSIDC的等面积SSM/I地球网格（EASE-Grid）格式进行发布。

EASE-Grid格式极大简化了将观测得到的海冰密集度或冰型，与通过卫星数据（如被动微波传感器反演得到的海冰密集度）推导得到的同类参数进行对比的流程。

采用EASE-Grid投影的AARI海冰数据，空间分辨率为12.5千米，覆盖西经24°至东经110°、东经105°至西经130°两个扇区，时间跨度为1953年至1990年。数据附带按年份绘制海冰覆盖范围的PostScript（.ps）文件。