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使用正斜压涡度拟能方程对一次乌拉尔山阻塞过程的研究表明，虽然正、斜压涡度拟能向阻塞区内的净输送、阻塞区域内正斜压涡度拟能的净生成以及β效应是阻塞环流建立、维持和崩溃的基本能源，但正斜压涡度拟能相互转换机制则是阻塞过程得以形成的根本原因。如果没有正斜压涡度拟能相互转化机制，则阻塞环流不但不能形成，反而使大气的斜压性不断增强，正压性不断减弱。 相似文献
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1 阻塞过程中正斜压涡度拟能相互转换机制的重要性 《山东气象》2002年第3期 朱乾根 南京气象学院 210044 摘要 使用正斜压涡度拟能方程对一次乌拉尔山阻塞过程的研究表明,虽然正、斜压涡度拟能向阻塞区内的净输送、阻塞区域内正斜压涡度拟能的净生成以及β效应是阻塞环流建立、维持和崩溃的基本能源,但正斜压涡度拟能相互转换机制则是阻塞过程得以形成的根本原因。如果没有正料压涡度拟能相互转化机制,则阻塞环流不但不能形成,反而使大气的斜压性不断增强,正压性不断减弱。 相似文献
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鄂霍茨克海阻高发展过程的正斜压涡度和涡度拟能的演变特征 总被引：2，自引：0，他引：2
用正斜压分解法，对1998年发生在鄂霍茨克海的阻高进行涡度和涡度拟以分析，结果发现：在阻高的不同阶段，正压涡度和正压涡度拟能远大于斜压涡度和斜压涡度拟能且在不同的阶段有着不同的演变过程；在阻塞的酝酿阶段正压和斜压涡度和涡度拟能不稳定增长，且向西南传播；在维持阶段，正压和斜压涡度和涡度拟能的增长达到最大值，阻塞形势建立并维持在阻塞区域内；在消亡阶段，正压涡度和涡度拟能与斜压涡度拟能则呈现出不稳定减少，向东南传播，阻塞崩溃，然后又增长。 相似文献
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正、斜压涡度拟能相互作用对乌拉尔阻塞过程的影响 总被引：1，自引：0，他引：1
研究表明,正压涡度拟能的增强和减弱是乌拉尔山上空阻塞过程的重要特征,正压涡度拟能增强的主要机制是斜压涡度拟能向正压涡度拟能的转换,而斜压涡度拟能的来源则是阻塞区外斜压涡度拟能向阻塞区的净输送和阻塞区内斜压涡度拟能的净生成。正压涡度拟能减弱的主要机制足耗散机制和β效应。因此。阻塞过程是正、斜压涡度拟能相互作用的结果。纬向斜压风对斜压涡度的输送在阻塞的维持和崩溃中具有重要的作用,经向斜压风对斜压涡度的输送在阻塞环流的建立中具有重要的作用,经向正压风对正压涡度拟能的净输送和斜压风对涡度拟能的净输送也具有重要贡献。 相似文献
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鄂霍茨克海阻高发展过程的正斜压涡度和涡度拟能的演变特征 总被引：2，自引：0，他引：2
用正斜压分解法,对1998年发生在鄂霍茨克海的阻高进行涡度和涡度拟能分析,结果发现在阻高的不同阶段,正压涡度和正压涡度拟能远大于斜压涡度和斜压涡度拟能且在不同的阶段有着不同的演变过程;在阻塞的酝酿阶段正压和斜压涡度和涡度拟能不稳定增长,且向西南传播;在维持阶段,正压和斜压涡度和涡度拟能的增长达到最大值,阻塞形势建立并维持在阻塞区域内;在消亡阶段,正压涡度和涡度拟能与斜压涡度和涡度拟能则呈现出不稳定减少,向东南传播,阻塞崩溃,然后又增长. 相似文献
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辽宁省春播期第一场透雨特征及其与鄂霍次克海阻塞高压的关系 总被引：1，自引：0，他引：1
《气象与环境学报》2016,(6)
利用1961—2013年4—5月辽宁省52个气象站逐日降水资料及NCEP/NCAR再分析资料,对辽宁省春播期第一场透雨特征进行了详细分析,并探讨了鄂霍次克海阻塞高压对辽宁省春播期第一场透雨的影响机制。结果表明:1961—2013年辽宁省春播期第一场透雨出现日期为4月17日至5月3日,平均出现日期为4月22日,辽宁省春播期第一场透雨出现的平均日期自东南向西北依次推后。鄂霍次克海阻塞高压是影响辽宁省春播期第一场透雨出现日期的主要环流系统,受鄂霍次克海阻塞高压的阻挡,冷空气在贝加尔湖附近堆积,在对流层低层鄂霍次克海阻塞高压激发了辽宁省北部地区的一个气旋式环流,水汽从孟加拉湾地区经中国中东部地区输送至辽宁地区,为辽宁地区春播期第一场透雨的出现提供了有利的必要条件。 相似文献
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瞬变波活动与江淮地区夏季旱涝的关系 总被引：3，自引：0，他引：3
利用1951-2000年中国160站逐月降水量资料划分了江淮地区夏季旱涝年。通过对旱涝年500hPa高度距平场的合成分析发现：多雨年鄂霍茨克海阻塞高压稳定维持，少雨年鄂霍茨克海附近的高压脊减弱。为了了解江淮地区旱涝年500hPa中高纬环流形势异常的原因，计算了Eliassen-Palm通量，结果表明多雨年瞬变波对平均气流的强迫作用使经、纬向风异常分布有利于鄂霍茨克海阻塞形势的维持，冷空气向南输送增强，江淮地区降水偏多；少雨年瞬变波对平均气流的强迫作用使鄂霍茨克海高压脊减弱，冷空气向南输送减弱，江淮地区降水偏少。 相似文献
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日本东部附近海域海温异常对鄂霍次克海高压的影响 总被引：4，自引：0，他引：4
通过诊断分析和数值模拟,研究了初夏日本东部附近海域负的海温异常对6月鄂霍次克海地区阻塞高压的影响。首先,利用1951—2000年6月份的500hPa月平均位势高度资料计算了历年6月鄂霍次克海阻塞高压指数,并分析了它的变化规律。其次,对阻塞高压年和非阻塞高压年的500hPa位势高度及其异常进行合成和相关分析表明,阻塞高压年,鄂霍次克海地区存在明显的正高度异常,贝加尔湖附近为负高度异常,乌拉尔山附近为正异常,欧亚中高纬度地区纬向呈“ - ”型;日本东部为负高度异常,东亚呈偶极型。这种高度异常形势为鄂霍次克海阻塞形势的形成和维持提供了大尺度环流背景。对鄂霍次克海阻塞高压指数与同期北太平洋海温的分析结果表明,当鄂霍次克海阻塞高压活跃时,日本东部附近海域为明显的负海温异常。此外,对1998年6月的典型个例的分析也发现,当年强盛的阻塞形势维持时,日本东部附近存在强大的负海温异常。最后,设计假想的负海温异常试验,利用NCAR CAM3模式模拟了日本东部附近海域负的海温异常对初夏欧亚大气环流的影响。结果表明,在该地区5和6月加入较大负的海温异常后6月份鄂霍次克海地区500hPa会产生最大超过4dagpm的正位势高度异常并经检验显著,这种正的高度异常显然对鄂霍次克海阻塞高压的形成十分有利。 相似文献
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根据ERA5(0.25°×0.25°)再分析资料和常规观测资料，对2018年11月初黑龙江省一次由黄海气旋爆发性发展引发的区域性暴雪过程进行深入分析。结果表明：极涡南下，其底部短波槽东移，与高原槽合并促使黄海气旋爆发性生长，同时鄂霍次克海阻高建立并稳定维持，是造成此次暴雪的重要原因。500-850 hPa偏南急流将东海、日本海及黄海的水汽源源不断向暴雪区域传递，并且与200 hPa西南急流相互耦合，进一步加强了上升运动，提供了暴雪产生的动力和水汽条件。低层低涡和地面气旋在北上过程中，其西侧不断有冷空气呈楔形入侵，强迫暖湿空气抬升使大气斜压性增强，在对流层中低层形成次级环流，同样是暴雪发生重要的动力抬升机制。在“冷空气楔”逐步北抬时，其上空始终存在湿正压项ζMPV1<0或湿正压项ζMPV1>0、湿斜压降ζMPV2<0，有明显低层湿对称不稳定，从而有利于暴雪产生。 相似文献
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正、斜压流场演变及相互转换所伴随的偶极型阻塞生命史 总被引：4，自引：1，他引：3
将阻塞过程中的大气运动流场分解为正,斜压流场,研究了它们在乌拉尔山偶极型阻塞个例中的演变特征。揭示了正、斜压流场的演变及相互转换所源发的阻塞生命史的全过程。 相似文献
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We discuss the nonlinear transfers possible in a quasigeostrophic fluid with a basic stratification taken from oceanic data. The energy and enstrophy conservation laws imply a cascade of energy to larger total scale (including both the horizontal scale, defined as wavelength/2π, and the deformation radius of the vertical mode). The triplet interactions among components with various horizontal scales and vertical structures, represented by the vertical mode numbers, are considered in detail for exchanges involving the barotropic and first three baroclinic modes. The initial transfer rates from one component into the other two are estimated and the most rapid transfers described as a function of the initial scale and mode number. These results suggest that barotropic motions will cascade to larger-scale barotropic motions, first baroclinic small-scale motions will transfer to first baroclinic larger scales, and first baroclinic large-scale motions will cascade to barotropic and first baroclinic motions at the deformation scale. Second and third mode motions prefer to transfer energy into small-scale (second or third mode deformation radius) first and third baroclinic mode motions.We also show the relationship of these triplet interactions to Rossby wave instabilities and resonant triads. For the latter motions, the weakness of the nonlinearity adds additional constraints which impty that the motions will tend to become zonal. 相似文献
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Conversion characteristics between barotropic and baroclinic circulations of the sah in its seasonal evolution 总被引：3，自引：0，他引：3
In the context of 1958-1997 NCEP/NCAR re-analyses, the South Asia high (SAH) was divided into two components, barotropic and baroclinic, the former based on mass weighed vertical integration and the latter on the difference between the measured circulation and the barotropic component counterpart, where upon the barotropic and baroclinic circulation conversion features were addressed of the research SAH during its seasonal variation. Evidence suggests that i) in summer (winter), the SAH is a thermal (dynamical) system, with dominant baroclinicity (barotropicity), either of the components accounting for approximately 70% of the total contribution; ii) as time progresses from winter to summer, accompanied by the barotropic SAH evolving into its baroclinic analog, the SAH is moving under the “thermal guidance” of its baroclinic component circulation, suggestion that the component circulation precedes the system itself in variation; iii) the reversal happens when it goes from summer to winter, with the SAH displacement under the “dynamic steering” of its barotropic component circulation. 相似文献
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NONLINEAR BAROTROPIC INSTABILITY INCLUDING FRICTION DISSIPATION,THERMAL DRIVING AND LARGE TOPOGRAPHY* 
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下载免费PDF全文 Lu Weisong 《Acta Meteorologica Sinica》1990,4(2):168-179
From a nonlinear quasi-geostrophic barotropic vorticity equation including frictional dissipation,thermal driving and large topography used by Charney in investigation of the multiple flow equilibria and blocking,using the Serrin-Joseph energy method and the variational principle,we found the nonlinear barotropic stability criteria of the zonal basic flow with the total energy,total enstrophy and their linear combination respectively,and compared the criteria with Charney's results. 相似文献
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In a barotropic atmosphere,new Reynolds mean momentum equations including turbulent viscosity,dispersion,and instability are used not only to derive the KdV-Burgers-Kuramoto equation but also to analyze the physical mechanism of the cascades of energy and enstrophy.It shows that it is the effects of dispersion and instability that result in the inverse cascade.Then based on the conservation laws of the energy and enstrophy,a cascade model is put forward and the processes of the cascades are described. 相似文献
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In a barotropic atmosphere, new Reynolds mean momentum equauons including turbulent viscosit,dispersion, and instability are used not only to derive the KdV-Burgers-Kuramoto equation but also to analyze the physical mechanism of the cascades of energy and enstrophy. It shows that it is the effects of dispersion and instability that result in the inverse cascade. Then based on the conservation laws of the energy and enstrophy, a cascade model is put forward and the processes of the cascades are described. 相似文献
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Changes in the normal mode energetics of the general atmospheric circulation are assessed for the northern winter season (DJF) in a warmer climate, using the outputs of four climate models from the Coupled Model Intercomparison Project, Phase 3. The energetics changes are characterized by significant increases in both the zonal mean and eddy components for the barotropic and the deeper baroclinic modes, whereas for the shallower baroclinic modes both the zonal mean and eddy components decrease. Significant increases are predominant in the large-scale eddies, both barotropic and baroclinic, while the opposite is found in eddies of smaller scales. While the generation rate of zonal mean available potential energy has globally increased in the barotropic component, leading to an overall strengthening in the barotropic energetics terms, it has decreased in the baroclinic component, leading to a general weakening in the baroclinic energetics counterpart. These global changes, which indicate a strengthening of the energetics in the upper troposphere and lower stratosphere (UTLS), sustained by enhanced baroclinic eddies of large horizontal scales, and a weakening below, mostly driven by weaker baroclinic eddies of intermediate to small scales, appear together with an increased transfer rate of kinetic energy from the eddies to the zonal mean flow and a significant increase in the barotropic zonal mean kinetic energy. The conversion rates between available potential energy and kinetic energy, C, were further decomposed into the contributions by the rotational (Rossby) and divergent (gravity) components of the circulation field. The eddy component of C is due to the conversion of potential energy of the rotational adjusted mass field into kinetic energy by the work realized in the eddy divergent motion. The zonal mean component of C is accomplished by two terms which nearly cancel each other out. One is related to the Hadley cell and involves the divergent component of both wind and geopotential, while the other is associated to the Ferrel cell and incorporates the divergent wind with the rotationally adjusted mass field. Global magnitude increases were found in the zonal mean components of these two terms for the warmer climate, which could be the result of a strengthening and/or widening of both meridional cells. On the other hand, the results suggest a strengthening of these conversion rates in the UTLS and a weakening below, that is consistent with the rising of the tropopause in response to global warming. 相似文献