A New Algorithm to Classify the Homogeneity of ERS-2 Wave Mode SAR Imagette

A new classification parameter is developed using 1535 ERS-2 wave mode synthetic aperture radar (SAR) test imagettes to better differentiate homogeneous and inhomogeneous imagettes. The comparison between the new parameter (Min) and the previous one (Inhomo) (Schulz-Stellenfleth and Lehner, 2004) was done under varied threshold values of Inhomo. It is concluded that the performance of ‘Min’ is much better than ‘Inhomo’ when applying to the 1535 test imagettes. Furthermore, both Min and Inhomo are applied to nearly 1 million imagettes collected for the period from 1 September 1998 to 30 November 2000. The comparisons of the global inhomogeneous distribution between ‘Min’ and ‘Inhomo’ reveal that both the areas and percentage of inhomogeneity calculated by ‘Min’ are larger than that calculated by ‘Inhomo’. By analyzing the low wind speed distribution of HOAPS data, we found that low wind speed over the ocean is one of the key reasons for the inhomogeneity of SAR imagettes.     

华北克拉通中元古代基性岩墙群形成机制及构造应力场

本文通过研究华北克拉通中部中元古代基性岩墙群的单体形态和分布规律,分析岩墙群形成的力学机制,认为这些基性岩墙群主要是基性岩浆侵位于先存的张性或张剪性破裂中而成。晋北地区和五台－太行山地区的岩墙群主要为张剪性的,吕梁山地区和中条山地区的主要为张性。根据岩墙群的分布规律、侵位方向和力学机制及其与燕辽－中条拗拉槽系之间的关系,认为华北克拉通中部中元古代的区域构造应力场是张性和张剪性构造环境,其主压应力来