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991.
Some Problems on the Global Wavelet Spectrum 总被引:2,自引:0,他引:2
WU Shu LIU Qinyu 《中国海洋大学学报(英文版)》2005,4(4):398-402
In order to test the validity of the global wavelet spectrum - a new period analysis method based on wavelet analysis, we carried out some simple experiments. In our experiments we used idealized time series and real Nifio 3 sea surface temperature (SST) for testing purposes. First we combined different signals which have the same power but different periods into some new time series. Then we calculated the global wavelet spectra and Fourier power spectra for the testing time series. The testing results revealed that on some occasions the global wavelet spectrum tends to amplify the relative power of longer periods. By making comparisons with the results obtained by the traditional Fourier power spectrum, we demonstrated that on an occasion when the global wavelet spectrum does not work the Fourier power spectrum can be used to achieve the right results. Hence it is recommended that when making period analysis with the global wavelet spectrum one needs to do further tests to confirm their results. 相似文献
992.
本介绍了上海天台长铯束管束光学系统改进后,扫描得到7条拉比台曲线和7条莱姆赛曲线。 相似文献
993.
994.
利用HTG-3型微波辐射计在乌鲁木齐机场进行试验验证期间获得的数据资料,采集了2016年10月—2017年1月出现的多个持续浓雾天气个例进行分析,结果表明:1)微波辐射计可以实时监测边界层温湿条件演变,有效弥补常规探空资料时间分辨率低的问题,可以在监测持续浓雾演变,研究持续浓雾的形成发展机制,提高临近预报能力上发挥有效作用;2)综合水汽含量(IWV)能够反映空中水汽消长情况。持续浓雾多是水汽缓慢耗散的过程。液态水路径(LWP)的增长波动变化与持续浓雾的生消变化有一定的对应;3)持续浓雾时地面到500~1000 m多为相对湿度95%以上高湿高饱和状态;4)贴地逆温的建立或加强是持续浓雾形成的关键。 相似文献
995.
996.
以2,6-二氯嘌呤为原料,微波辐射法合成了"Reversine"[1,2-(4-吗啉苯胺基)-N6-环己基腺嘌呤]的重要中间体2-氯-6-环己胺基嘌呤及其衍生物3b~3f,再以2-氯-6-环己胺基嘌呤为原料,微波辐射下合成了2-苯胺基-6-环己胺基嘌呤及"Reversine"。探索了合适的反应条件及影响因素,产物的结构通过1 H NMR进行了表征。研究表明,微波法可大幅提高合成嘌呤2,6位衍生物收率并缩短反应时间,为嘌呤衍生物及"Reversine"的合成提供了一种绿色、简洁高效的合成方法。 相似文献
997.
上海天文台时间频率研究室以原有被动型氢钟物理部分为基础,开展了脉冲微波式氢原子钟的研究。设计电路产生2个相干微波脉冲,连续激励氢原子跃迁,模拟双腔共振,使氢原子发生Ramsey干涉,压缩氢原子跃迁谱线宽度,以期提高氢原子钟短期稳定度指标。具体做法为:用DDS产生扫频电路,混频生成1.420 405 GHz激励信号后,再用CPLD产生脉冲时序控制数字衰减器,将激励信号衰减为脉冲形式,激励氢原子发生Ramsey干涉,导出微波信号并进行相关处理就可以产生Ramsey条纹。已观测到Ramsey干涉条纹,其中心峰宽度为1.2 Hz,相比传统被动型氢原子钟压缩了60%。 相似文献
998.
Assessment of the initial sea surface temperature product of the scanning microwave radiometer aboard on HY-2 satellite 总被引:4,自引:3,他引:1
ZHAO Yili ZHU Jianhu LIN Mingsen CHEN Chuntao HUANG Xiaoqi WANG He ZHANG Youguang PENG Hailong 《海洋学报(英文版)》2014,33(1):109-113
HY-2 satellite is the first satellite for dynamic environmental parameters measurement of China,which was launched on 16th August 2011.A scanning microwave radiometer(RM) is carried for sea surface temperature(SST),sea surface wind speed,columnar water vapor and columnar cloud liquid water detection.In this paper,the initial SST product of RM was validated with in-situ data of National Data of Buoy Center(NDBC) mooring and Argo buoy.The validation results indicate the accuracy of RM SST is better than 1.7 C.The comparison of RM SST and WindSat SST shows the former is warmer than the latter at high sea surface wind speed and the difference between these SSTs is depend on the sea surface wind speed.Then,the relationship between the errors of RM SST and sea surface wind speed was analyzed using NDBC mooring measurements.Based on the results of assessment and errors analysis,the suggestions of taking account of the affection of sea surface wind speed and using sea surface wind speed and direction derived from the microwave scatteromter aboard on HY-2 for SST product calibration were given for retrieval algorithm improvement. 相似文献
999.
A preliminary assessment of the sea surface wind speed production of HY-2 scanning microwave radiometer 总被引:3,自引:3,他引:0
HUANG Xiaoqi ZHU Jianhu LIN Mingsen ZHAO Yili WANG He CHEN Chuntao PENG Hailong ZHANG Youguang 《海洋学报(英文版)》2014,33(1):114-119
A scanning microwave radiometer(RM) was launched on August 16,2011,on board HY-2 satellite.The six-month long global sea surface wind speeds observed by the HY-2 scanning microwave radiometer are preliminarily validated using in-situ measurements and WindSat observations,respectively,from January to June 2012.The wind speed root-mean-square(RMS) difference of the comparisons with in-situ data is 1.89 m/s for the measurements of NDBC and 1.72 m/s for the recent four-month data measured by PY30-1 oil platform,respectively.On a global scale,the wind speeds of HY-2 RM are compared with the sea surface wind speeds derived from WindSat,the RMS difference of 1.85 m/s for HY-2 RM collocated observations data set is calculated in the same period as above.With analyzing the global map of a mean difference between HY-2 RM and WindSat,it appears that the bias of the sea surface wind speed is obviously higher in the inshore regions.In the open sea,there is a relatively higher positive bias in the mid-latitude regions due to the overestimation of wind speed observations,while the wind speeds are underestimated in the Southern Ocean by HY-2 RM relative to WindSat observations. 相似文献
1000.