基于雷达高度计的辽东湾海冰外缘线提取及其变动规律

Extraction and variation analysis of outer edge of sea ice in Liaodong Bay based on radar altimeter data

为了分析利用雷达高度计资料提取海冰外缘线的精度,推进高度计在中国海冰遥感监测中的应用进展,本研究中基于Jason-2高度计沿岸和水文专用产品(PISTACH),提取了2008—2016年间辽东湾海冰外缘线,并与高分一号(GF-1)观测结果进行了对比验证,最后分析了辽东湾外缘线变动与国家海洋局葫芦岛海洋站气温观测数据的关系。结果表明:2013年末至2016年初3个冰期内的验证试验显示,基于Jason-2高度计判定的海冰外缘线延伸范围与基于GF-1遥感影像提取的结果符合良好,两者提取的海冰外缘线延伸距离均方差为2.81 n mile,并且海冰外缘线变动规律与气温数据变动规律一致;对2008年6月—2016年10月期间共8个冰期的辽东湾海冰外缘线的变动规律分析显示,2010年冰情最为严重,辽东湾海冰外缘线自海岸起沿Jason-2高度计轨道往南延伸约90 n mile,2014年和2015年的冰情较轻,延伸距离均小于40 n mile,另外,延伸距离的变动与葫芦岛的10日滑动平均气温呈明显的滞后响应关系,当滞后4 d时,两者的相关性最强,相关系数为-0.56。研究表明,基于雷达高度计资料可以准确地提取辽东湾海冰外缘线,本研究结果对于中国海冰数据产品的开发和数值模拟的改进与验证具有重要参考。

In order to analyze the accuracy of sea ice edge via extracting by radar altimeter data and promote application progress of altimeter in sea ice remote sensing monitoring in China,the sea ice outer edges of Liaodong Bay from 2008 to 2016 were extracted based on the waveform types of Jason-2 altimeter coastal and hydrological PISTACH products,and the relationship between the variation of the outer edges of Liaodong Bay and the temperature of Huludao observation station are evaluated.The verification tests in the three ice ages from the end of 2013 to the beginning of 2016 showed that the extension range of the sea ice outer edges determined by Jason-2 altimeter was in good agreement with the results extracted from Gaofen-1 images,with mean square deviation of 2.81 n miles in the extension distance.The variation of sea ice outer edge was consistent with that at Huludao observation station by Dalian Marine Environment Monitoring Center.The variation analysis of the ice edge in Liaodong Bay in 8 sea ice periods from June 2008 to October 2016 showed that the ice condition was the most serious in 2010.The outer edge of Liaodong Bay extended about 90 n miles south along the Jason-2 altimeter track from the coast.The ice conditions were found to be light in 2014 and 2015,with the extension distances of less than 40 n miles.There was an obvious lag variation of extension distance with response to the 10 day moving average temperature in Huludao,with the maximal correlation between them at lag of 4 days,and the correlation coefficient of-0.56.The finding showed that the outer edge of sea ice was extracted effectively based on radar altimeter data,which is of great significance for the development of sea ice data and the improvement and verification of numerical simulation in China.