Radar backscattering changes in Arctic sea ice from late summer to early autumn observed by space-borne X-band HH-polarization SAR
Radar backscattering changes in Arctic sea ice from late summer to early autumn observed by space-borne X-band HH-polarization SAR
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DOI：
10.1080/2150704x.2016.1165881
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发表时间：
2016-04
影响因子：
2.3
通讯作者：
Jeong-Won Park;Hyun‐cheol Kim;Sang‐Hoon Hong;Sung-Ho Kang;H. Graber;B. Hwang;Craig M. Lee
中科院分区：
文献类型：
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作者：
Jeong-Won Park;Hyun‐cheol Kim;Sang‐Hoon Hong;Sung-Ho Kang;H. Graber;B. Hwang;Craig M. Lee
摘要融化池被认为在海冰动力学中起着重要的作用，因为它们在温暖的春季和夏季加速了海冰的融化。此外，它们吸收太阳辐射，而不是像周围的海冰那样反射太阳辐射。然而，融化池的大小和分布是高度可变的，因此，融化池对海冰融化的贡献应该根据融化池的成熟度而有所不同。由于北极的恶劣条件，很难通过现场测量和/或光学遥感数据来估计实际的地表变化。在这项研究中，我们提出了一个高分辨率的时间序列分析的短期变化的海冰和融化池在博福特海使用星载多光谱和合成孔径雷达（SAR）图像。使用KOMPSAT-3（韩国多用途卫星-3）光学图像对地表类型进行初步分类，并使用2014年北极夏季46天的15张TerraSAR-X SAR图像进行密集时间序列分析。根据光谱特征将目标海冰表面分为6类。雷达后向散射系数的时间变化在每一类表现出不同的模式，这是密切相关的表面变化。总体而言，雷达后向散射系数的变化表明动态表面的变化，除了压力脊。所有的冰类显示了两个步骤减少雷达后向散射，而积雪覆盖的冰面表现出少得多的变化相比，裸露的冰面。邻近池塘的表面显示出比其他类更强的负下降。与蓝色融化池的逐步减少不同，深色融化池等级的变化呈现复杂的非线性减少。这些观测可用于地表融化/冻结速率的重要建模研究，并利用遥感数据推断大面积的变化。
ABSTRACT Melt ponds are believed to play an important role in sea ice dynamics because they accelerate the melting of sea ice in the warmer spring and summer months. Additionally, they are known to absorb solar radiation rather than reflect it as the surrounding sea ice does. However, the size and distribution of melt ponds are highly variable, and thus, the contribution of melt ponds to sea ice melting should differ based on the maturity of the melt pond. Because of the harsh conditions of the Arctic, estimating the actual surface changes via in situ measurements and/or optical remote sensing data is difficult. In this study, we present a high-resolution time-series analysis of the short-term variation of sea ice and melt ponds over the Beaufort Sea using space-borne multispectral and synthetic aperture radar (SAR) images. A KOMPSAT-3 (Korea Multi-Purpose Satellite-3) optical image was used for an initial classification of the surface types, and 15 TerraSAR-X SAR images covering 46 days in the 2014 Arctic summer were used to perform a dense time-series analysis. The surface of the target sea ice was classified into six categories based on spectral characteristics. The temporal variation of the radar backscattering coefficient in each class exhibited a distinct pattern, which was closely related to surface changes. Overall, changes in the radar backscattering coefficient indicated dynamic surface changes, except over pressure ridges. All ice classes showed a two-step decrease in radar backscattering, whereas snow-covered ice surfaces exhibited far fewer changes compared to bare ice surfaces. The surfaces adjacent to ponds showed stronger negative decreases than other classes. The changes in dark melt pond classes presented a complex non-linear decrease, which differed from the stepwise decrease of blue melt ponds. These observations can be used for important modelling studies of surface melting/freezing rates and to infer the variation over large areas using remote sensing data.