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ANALYSIS ON CHARACTERISTICS OF ATMOSPHERIC DUCT AND ITS EFFECTS ON THE PROPAGATION OF ELECTROMAGNETIC WAVE 总被引:1,自引:0,他引:1
On the basis of introducing the basic categories of atmospheric refraction and their existingconditions,the forming processes of three kinds of atmospheric ducts are expounded.Several maincharacteristics of atmospheric duct are summarized and analyzed,and field sounding data from theWEstern North-Pacific cloud-radiation EXperiment(WENPEX)and meteorological data aroundthe Xisha sea area are used to validate these characteristics.Meanwhile the sensitivities of theevaporation duct height to the variations of atmospheric humidity.the air-sea temperaturedifference.and horizontal wind speed are examined.With the analysis of the effect of atmosphericduct on the propagation of electromagnetic wave.the maximum trapped-wavelength and the criticalemitting angle of elevation for electromagnetic wave which can form duct propagation are derived.At the same time the four kinds of necessary conditions for electromagnetic wave to form ductpropagation are brought forward.The effects of atmospheric duct on ultrashort wave propagation,radar observation.short wave communication etc.are also discussed. 相似文献
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遥感环境已有二十多年的历史了。按物理性质,遥感技术可分微波、红外光、可见光三种,它们可以独立地使用,也可互相配合使用。本文主要介绍微波遥感技术及其在气象学上应用的近况。微波遥感如从地面遥感大气的温、压、湿层结,又可叫作“无球探空”。无球探空的机动性强,仪器可以携带转移,用来观测局地的气象状况;它每次观测大约需三十分钟,可以连续观测、监视大气状态的变化,因此增用遙感技术可使探空网在时间上和空间上增加密度。无球探空只“被动”接收来自大气的自然辐射信号,本身没有发射能力,便于隐蔽,适合战时需要。 相似文献
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On the basis of extracting the clear brightness temperature in GMS-4 infrared data,the testshave been carried out by using three methods for SST retrieval in the northwestern Pacific Ocean inAugust 1993.Considering error amplification is the inherent feature in the single channel physicalmethod,two statistical methods are developed.One is a single channel method.Its precision is1.186℃,which is superior to that of other similar methods.The other is a multi-channel methodusing both TOVS and GMS-4 data.Its precision is 1.061℃,which is matched with that of othercurrent multi-channel statistical methods(0.5—1.36℃).The retrieval SST distributions obtainedby the two methods are in good agreement with conventional observations. 相似文献
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针对2002年6月23—27日发生于江淮地区的一次中尺度强暴雨过程,利用FY-1D,EOS和NOAA卫星的可见光、红外、微波通道遥感观测、反演资料,从相态、光学厚度、垂直结构等各方面分析云特征,并将分析结果与同时段地面雨量观测进行对比分析,发现云光学厚度大且云顶粒子为大粒子、冰相态是此次降雨过程中云团的主要云特征,地面雨量的大小与云光学厚度密切相关,两者间基本呈正相关关系;稳定少变的大光学厚度云或云光学厚度显著增大均可带来强的地面降水。微波资料可以很好地体现降雨云团的垂直结构。分析结果显示,卫星遥感对揭示中尺度强暴雨云团的云特征,具有很好的指示作用。 相似文献
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本文讨论了在自然过冷云中的冰水转化过程,和降水元产生的情况。从计算的结果指出,过去用的静止、等温、成冰核匀谱的冰水转化过程,不能很好地反映真实的云中状况。上升气流,成冰核谱、非等温效应等对于冰水转化过程有很大的影响。 相似文献
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本文讨论了在干冰球附近冰晶胚胎生成的机制,并研究了干冰球在过冷云中蒸发的过程。和实验的结果比较,得到一致的结论。 相似文献