Sea Ice Index: ice cover and trends in ice cover in the Arctic and Antarctic oceans, Version 3, 1978-present

The Sea Ice Index provides a quick look at Arctic- and Antarctic-wide changes in sea ice. It is a source for consistent, up-to-date sea ice extent and concentration images, in PNG format, and data values, in GeoTIFF and ASCII text files, from November 1978 to the present. Sea Ice Index images also depict trends and anomalies in ice cover calculated using a 30-year reference period of 1981 through 2010.
The images and data are produced in a consistent way that makes the Index time-series appropriate for use when looking at long-term trends in sea ice cover. Both monthly and daily products are available. However, monthly products are better to use for long-term trend analysis because errors in the daily product tend to be averaged out in the monthly product and because day-to-day variations are often the result of short-term weather.
Fetterer, F., K. Knowles, W. N. Meier, M. Savoie, and A. K. Windnagel. 2017, updated daily. Sea Ice Index, Version 3. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: https://doi.org/10.7265/N5K072F8. 13 Nov 2020.

海冰指数（Sea Ice Index）可快速展示北极与南极全域的海冰变化情况。该数据集提供自1978年11月至今的一致化、实时更新的海冰范围与密集度图像（格式为PNG），以及对应的数据值文件（格式为GeoTIFF与ASCII文本文件）。海冰指数图像还可展示以1981至2010年这30年为参考时段计算得到的海冰覆盖趋势与异常值。
所有图像与数据均采用统一标准生成，使得该指数的时间序列数据集适用于海冰覆盖长期趋势分析。数据集同时提供月度与单日产品。不过在长期趋势分析中更推荐使用月度产品：一方面单日产品的误差可在月度统计中被平均抵消，另一方面单日海冰变化往往由短期天气事件导致。
Fetterer F.、Knowles K.、Meier W. N.、Savoie M.、Windnagel A. K.，2017年，每日更新。海冰指数（版本3）。美国科罗拉多州博尔德市：国家冰雪数据中心（National Snow and Ice Data Center, NSIDC）。DOI：https://doi.org/10.7265/N5K072F8。2020年11月13日。