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191.
为了研究整个对流层中水平扩散系数(Ky)随高度变化的参数化形式以及平流格式的数值扩攻对物质浓度分布的影响及二者对模式结果影响的相互关系,本文用“高分辨对流层物质交换模式”(EM3)对三咱不同KY参数化型能对行星边界层(PBL)内受下垫面影响的高湍流PBL以上整个对流层受水平风切变产生的切变湍流分层结构具有良好的描述能力;模式采用几乎无数值扩散二阶矩守恒的Prather平流差分格式代替模式Smola 相似文献
192.
In order to understand the activity characteristics of low-level jets in the Nanjing area, statistical analysis and comparative study are carried out on their monthly and diurnal variations, characteristics of their cores and accompanying weather conditions using wind profile data in 2005—2008 collected by two wind profilers. The results show that low-level jets have significant monthly and diurnal variations. They occur more frequently in spring and summer than in autumn and winter and are more active in early morning and at night, with the maximum wind speed usually occurring at midnight. The central part of the low-level jet occurs mainly at the height of less than 1400 meters, and the enhancement of central speed is beneficial to the appearance of precipitation. Meanwhile, when the low-level jet appears in summer, it helps cause heavy rain. The statistical results of the boundary wind profiler are well consistent with those of the tropospheric wind profiler. Two kinds of wind profilers also have the capability of continuously detecting the development of low-level jets. 相似文献
193.
GPS接收机内噪声水平的评价与检测方法 总被引:2,自引:1,他引:1
论文结合某品牌GPS接收机检测实例,提出了GPS接收机内噪声水平分布统计的评价方法,以及在超短基线场内GPS接收机内噪声水平的全新检测方法———多时段旋转检测台法。实例测试,按本方法得到的被测试GPS接收机内噪声水平标准差为0.38mm。由测试实例得到如下结论:本文的GPS接收机内噪声水平评价方法以及检测方法更加合理、可信;在超短基线场内多时段测得的同一基线长度互差应小于2mm;GPS接收机系统软件的抗噪性能对内噪声水平有着非常重要的影响。 相似文献
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NumericalstudiesofupwellingincoastalareasoftheEastChinaSea-ⅠThetide-inducedupwellingLuoYiyong,YuGuangyao,HuangZuke(ReceivedOc... 相似文献
196.
A simple model of lower trophic level ecosystem has been created to analyze possible environmental control of primary production
in eight sub-areas of the Seto Inland Sea. The primary production rates observed by Hashimotoet al. (1997a) in these sub-areas are well reproduced by the model, including horizontal processes such as horizontal transport
of nutrients and vertical processes such as vertical mixing, light intensity and sinking of particulate matter. Without taking
account of horizontal processes the model also successfully reproduces the observed primary production rates in some areas,
but if fails to reproduce those in the others. This shows that the relative importance of the horizontal transport on the
primary production differs are by area. Two time scales,T
z andT
H, are introduced to explain this difference.T
z is a vertical cycling time of material, which is defined as the time during which the stock of the material in the water
column is utilized for primary production;T
H is the horizontal transit time of the material. The relative importance of the horizontal process is well explained by theT
H/T
z ratio; that is, the horizontal transport process is important in the areas where this ratio is small. Further the possible
mechanisms of nutrient supply for the primary production in each sub-area are investigated using this model. 相似文献
197.
GUAN Changlong Professor 《中国海洋工程》1998,(3)
On the basis of the linear model of random sea waves presented by Longuet-Higgins,the statis-tical distribution of the horizontal velocities of water particles at wave surface maxima is derivedtheoretically.The derived distribution is similar to that of wave surface maxima,and a new spectral widthε_u,which is defined as(1-(m_3~2/m_2m_4))~(1/2),is introduced in the distribution.When ε_u tends to zero,the distribu-tion is reduced to Rayleigh distribution and it is reduced to the normal distribution when ε_u tends to unity.For a narrow spectrum,it is proved that ε is equal to 1/2ε,where ε is(1-(m_2~2/m_0m_4))~(1/2)and is the commonlyused spectral width.. 相似文献
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