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1.
X.B. Zhao W.Z. Shao L.B. Zhao Y. Gao Y.Y. Hu X.Z. Yuan 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2021,67(10):3072-3086
The main objective of our work was to investigate the impact of rain on wave observations from C-band (~5.3 GHz) synthetic aperture radar (SAR) in tropical cyclones. In this study, 10 Sentinel-1 SAR images were available from the Satellite Hurricane Observation Campaign, which were taken under cyclonic conditions during the 2016 hurricane season. The third-generation wave model, known as Simulating WAves Nearshore (SWAN) (version 41.31), was used to simulate the wave fields corresponding to these Sentinel-1 SAR images. In addition, rainfall data from the Tropical Rainfall Measuring Mission satellite passing over the spatial coverage of the Sentinel-1 SAR images were collected. The simulated results were validated against significant wave heights (SWHs) from the Jason-2 altimeter and European Centre for Medium-Range Weather Forecasts data, revealing a root mean square error (RMSE) of ~0.5 m with a 0.25 scatter index. Winds retrieved from the VH-polarized Sentinel-1 SAR images using the Sentinel-1 Extra Wide-swath Mode Wind Speed Retrieval Model after Noise Removal were taken as prior information for wave retrieval. It was discovered that rain did indeed affect the SAR wave retrieval, as evidenced by the 3.21-m RMSE of SWHs between the SAR images and the SWAN model, which was obtained for the ~1000 match-ups with raindrops. The raindrops dampened the wave retrieval when the rain rate was < ~5 mm/hr; however, they enhanced wave retrieval for higher rain rates. It was also found that the portion of the rain-induced ring wave with a wave number > 0.05 rad/m (~125 m wavelength) was clearly observed in the SAR-derived wave spectra. 相似文献
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应用伏特拉级数法分析了电容耦合FET振荡系统在外加信号下的注入锁定现象,推导出输出信号和注入锁定带宽表达式。与一般非线性系统分析方法相比,伏特拉级数法在建立好系统模型后只需进行代数运算,从而避开了求解非线性,非齐次高阶微分方程的复杂过程。 相似文献
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弹道交班自适应算法研究 总被引:1,自引:0,他引:1
为实现复合制导不同制导弹道的平滑过渡,用二阶吻合法设计了一不同制导律间的指令交接导引段。建立了自适应弹道交接导引算法的模型。理论分析和仿真结果表明,该算法具较好的弹道过载平滑能力,有一定的应用价值。 相似文献
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对某型号制导雷达部分元器件进行了失效分析,找出了导致元器件失效的原因,指出设计是提高可靠性的关键,并根据有关元器件情况对生产方与使用方提出了建议。着重讨论了设计师应注意的问题和应该遵循的设计原则。针对失效情况,提出了一些具体的设计构想。 相似文献
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英语比较动词是用来表达级差这一逻辑意义的一类较特殊的动词。英语比较动词的数量虽不如形容词、副词比较级丰富,但仍是构成英语比较语义系统不可忽视的环节。本文系统探讨了英语比较动词的语义、语法与形态学特征,以及相关语义动词的比较级分类,并在对比分析的基础上推演出英语比较动词的不同类别,从而加强了对英语比较动词的了解和认识。 相似文献
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Large amplitude MHD waves are commonly found in the solar wind. Nonlinear interactions between the MHD waves are likely to
produce finite correlation among the wave phases. For discussions of various transport processes of energetic particles, it
is fundamentally important to determine whether the wave phases are randomly distributed (as assumed in quasi-linear theories)
or they have a finite coherence. Using a method based on a surrogate data technique and a fractal analysis, we analyzed Geotail
magnetic field data (provided by S. Kokubun and T. Nagai through DARTS at the Institute of Space and Astronautical Science)
to evaluate the phase coherence among the MHD waves in the earth's foreshock region. The correlation of wave phases does exist,
indicating that the nonlinear interactions between the waves is in progress.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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