基于Argo浮标的南极海冰范围变化分析

南极海冰的生消冻融与全球气候变化息息相关,多年以来受到国际社会的高度关注。目前已有诸多关于南极海冰范围变化的研究,但大部分是基于卫星遥感影像来展开分析。Argo观测网遍布全球各大洋,为海冰范围研究提供了一种新的思路,即根据浮标GPS点的南部边界推算南极海冰边界,由浮标的年、月累积数据得到南极海冰范围的年际、月际变化规律。对于这种研究思路提出了三种实现方法:(1)绘制专题图,可以清晰直观地看到南极海冰在2—9月间的生消变化情况;(2)利用南极附近浮标GPS点数量占全球比例的变化情况来分析海冰变化规律,在月际变化趋势上与影像数据一致,在年际变化上稍显不足;(3)使用点密度分析方法估计海冰边界,建立基于浮标GPS点密度的海冰-海水分界模型,可得到南极海冰范围变化规律的定量分析结果。浮标数据与影像数据互为补充,可为全球气候变化研究提供更多参考。

Analysis of Antarctic sea ice extent variation based on Argo floats

The generation and melting of Antarctic sea ice is closely related to the global climate change and has attracted the attention of the international community. There are various studies on Antarctic sea ice extent, but they are mostly based on satellite remote sensing images. Argo observation network covers all oceans around the world, providing a new way for the study of sea ice, that is, to estimate Antarctic sea ice extent according to the southern edge of the float GPS points, and analyze the annual and monthly variation of Antarctic sea ice extent from the accumulated float data. To realize this idea, three methods are proposed: (1) drawing thematic maps, which can clearly show the variation of Antarctic sea ice extent between February and September; (2) using the proportions of float GPS point numbers near Antarctic to the global ones to analyze the variation of Antarctic sea ice extent, which agrees with the image data in monthly variation trend, but performs slightly poorly in annual variation trend; (3) estimating Antarctic sea ice boundary by point density analysis method and establishing ice-water border model based on the float GPS point density, which provides the quantitative results of sea ice extent variation. Float data and image data can complement each other, and benefit further to the global climate change research.