期刊文献+
共找到50篇文章
< 1 2 3 >
每页显示 20 50 100
北半球温带气旋的变化 被引量:23
1
作者 王新敏 邹旭恺 翟盘茂 《气候变化研究进展》 CSCD 2007年第3期154-157,共4页
许多学者对近半个世纪以来温带气旋的频数、强度和路径的年际、年代际变化等特征进行了研究,并探讨了温带气旋变化与大气环流的关系,试图揭示气候变暖背景下温带气旋变化的可能原因。较为一致的研究结论是:在全球变暖背景下,北半球气旋... 许多学者对近半个世纪以来温带气旋的频数、强度和路径的年际、年代际变化等特征进行了研究,并探讨了温带气旋变化与大气环流的关系,试图揭示气候变暖背景下温带气旋变化的可能原因。较为一致的研究结论是:在全球变暖背景下,北半球气旋活动的变化显示出在中纬度明显减少,而在高纬度增加的趋势,意味着气旋的路径已经明显地北移。研究还表明,气旋活动的变化与对流层斜压性、急流以及北大西洋涛动、海温梯度等因素有关。 展开更多
关键词 温带气旋 气候变暖 斜压不稳定 NCEP/NCAR再分析资料 海平面气压
下载PDF
湿位涡诊断分析在河南台风远距离降水中的应用 被引量:23
2
作者 范学峰 席世平 《气象与环境科学》 2012年第2期25-32,共8页
应用湿位涡理论,分析了两个发生在河南的台风远距离降水个例,讨论了湿位涡与台风远距离降水形成的关系。结果表明:两个个例中,河南具有有利于强降水发生的湿位涡特征;异常暴雨的发展与湿位涡的变化有很好的对应关系:湿位涡的异常区域对... 应用湿位涡理论,分析了两个发生在河南的台风远距离降水个例,讨论了湿位涡与台风远距离降水形成的关系。结果表明:两个个例中,河南具有有利于强降水发生的湿位涡特征;异常暴雨的发展与湿位涡的变化有很好的对应关系:湿位涡的异常区域对应着最强的降水,对流层高层ζMPV1(湿位涡的垂直分量)正值区与低层ζMPV2负值区相互作用,即高层下滑的干冷空气与中低层由东南急流输送的高温高湿空气交汇,容易储存和释放湿对流不稳定能量,有利于强降水产生。湿位涡理论在河南台风远距离降水诊断中有很好的应用前景。 展开更多
关键词 湿位涡 垂直分量 水平分量 台风远距离暴雨 斜压不稳定
下载PDF
南疆盆地翻山型沙尘暴环流动力结构分析 被引量:21
3
作者 杨莲梅 张广兴 杨青 《中国沙漠》 CSCD 北大核心 2006年第1期71-76,共6页
2003年4月8日至9日发生了一次超极地冷空气入侵新疆并翻越天山造成南疆盆地大范围强沙尘暴过程,分析沙尘暴强盛期的高度场、高空急流异变、螺旋度场、散度场和不稳定发展,揭示了该类沙尘暴强盛期的环流动力结构。结果表明:①伊朗高压的... 2003年4月8日至9日发生了一次超极地冷空气入侵新疆并翻越天山造成南疆盆地大范围强沙尘暴过程,分析沙尘暴强盛期的高度场、高空急流异变、螺旋度场、散度场和不稳定发展,揭示了该类沙尘暴强盛期的环流动力结构。结果表明:①伊朗高压的爆发性发展与乌拉尔山脊叠加形成长波脊,导致泰米尔半岛的极地强冷空气南下,并直插新疆越过天山到达塔里木盆地,造成大范围沙尘暴天气;②强沙尘暴天气产生的根本原因是西西伯利亚地面冷高压爆发性南下并强烈发展;③高空西风急流发生异变在南疆盆地上空形成急流区,并通过动量下传导致地面大风,是大范围沙尘暴发生的动力条件;④沙尘暴区上空螺旋度垂直分布低层为正值、高层为负值,揭示强的旋转上升运动是大范围沙尘暴发生的动力条件。⑤低层辐合高层辐散的垂直结构,易于发生近地面大风和上升气流;⑥该次沙尘暴是一次大范围强对流天气,大气层结处于对流中性或对流不稳定状态,但都有强的斜压不稳定发展,并冷暖空气交换剧烈。沙尘暴影响前塔里木盆地有一个能量明显聚集期,但聚集时间很短。 展开更多
关键词 翻山型沙尘暴 动力结构 高度场 高空急流异变 螺旋度场 散度场 不稳定发展
下载PDF
太平洋北赤道流区上层海洋季节内振荡及斜压稳定性 被引量:10
4
作者 刘秦玉 潘爱军 刘征宇 《海洋与湖沼》 CAS CSCD 北大核心 2003年第1期94-100,共7页
根据全球高分辨率的海洋环流模式 (POCM)的数值模拟结果 ,发现北赤道流区上层海洋流的季节内变化是以准 60天振荡为主 ,该准 60天振荡的振幅有年际变化。利用 2 .5层海洋模式 ,确定了NEC区纬向Rossby波解的频散关系。该关系表明 :北赤... 根据全球高分辨率的海洋环流模式 (POCM)的数值模拟结果 ,发现北赤道流区上层海洋流的季节内变化是以准 60天振荡为主 ,该准 60天振荡的振幅有年际变化。利用 2 .5层海洋模式 ,确定了NEC区纬向Rossby波解的频散关系。该关系表明 :北赤道流区行星波和波长小于 5 70km的Rossby波都为稳定波 ;波长小于 2 0 0 0km ,大于 5 70km的Rossby为不稳定波 ;最不稳定波的相速度和波长分别为 - 0 .1 45m·s- 1 和 785km。斜压不稳定是北赤道流区上层海洋准 展开更多
关键词 太平洋 北赤道流 准60天振荡 斜压稳定性 形成机制 海洋环流模式
下载PDF
“罗莎”台风造成浙江特大暴雨的过程分析 被引量:13
5
作者 曾欣欣 黄新晴 滕代高 《海洋学研究》 2010年第1期62-71,共10页
0716号台风"罗莎"于2007年10月7日下午15:30在浙江省苍南县霞关镇附近的浙闽交界处登陆。受"罗莎"台风的影响,浙江省出现暴雨到大暴雨,过程平均降雨量全省达163.0mm。利用NCEP/NCAR1°×1°再分析格点... 0716号台风"罗莎"于2007年10月7日下午15:30在浙江省苍南县霞关镇附近的浙闽交界处登陆。受"罗莎"台风的影响,浙江省出现暴雨到大暴雨,过程平均降雨量全省达163.0mm。利用NCEP/NCAR1°×1°再分析格点资料、浙江省自动站降水数据和MICAPS的Ki与Ky指数资料(浙江省部分),对由0716号台风"罗莎"造成的浙江大暴雨到特大暴雨过程的大环流天气形势演变、动力条件、水汽输送及物理量特征等进行诊断研究。结果表明,在10月6~9日"罗莎"台风影响浙江期间,欧亚500hPa中高纬度为平直环流,乌拉尔山以西为高压脊,从河西走廊至中原地区有一移动性冷槽,西太平洋副热带高压逐渐加强,呈东西向带状,位置偏北强度偏强,江淮以南地区为副热带高压控制,脊线位于30°N附近;在对流层中、低层(气压为700hPa、850hPa)有明显的冷温槽,途经河西走廊、河套地区、江淮和长江中下游地区,7日14时至8日14时地面冷锋与"罗莎"台风倒槽在浙江相互作用,形成了台风外围受冷空气侵入的特定环境场,为浙江大暴雨到特大暴雨的形成创造了条件。"罗莎"台风螺旋云带中含有大量水汽从东海向浙江大陆输送,10月6日20时至8日14时,从东海到浙江大部出现强的水汽通量大值区,最大水汽通量出现在10月7日02时低层(气压为850hPa),中心为40g/(s.hPa.cm)以上的水汽通量大值区出现在东海,低层高含水量从东海向浙江陆地持续输送,时间长达42h,为本次大暴雨到特大暴雨提供了有利的水汽条件,诊断得出,大气柱可降水量达65kg/m2时可出现大到暴雨,大气柱可降水量达70kg/m2时可出现特大暴雨。从流场、散度场和垂直速度场发现,台风环流区域内低层的强上升运动为本次大暴雨到特大暴雨提供了上升运动的促发机制,高层辐散区与中低层台风北侧倒槽强烈辐合区叠加,使得中低层的辐合更为强烈,这都有利于台风北侧暴雨的� 展开更多
关键词 暴雨 水汽输送 环流特征 上升运动 辐合辐散 斜压不稳定
下载PDF
Seasonal variation of eddy kinetic energy in the South China Sea 被引量:11
6
作者 WANG Hui WANG Dakui +2 位作者 LIU Guimei WU Huiding LI Ming 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2012年第1期1-15,共15页
Mesoscale eddy activity and its modulation mechanism in the South China Sea (SCS) are inves- tigated with newly reprocessed satellite altimetry observations and hydrographic data. The eddy kinetic energy (EKE) lev... Mesoscale eddy activity and its modulation mechanism in the South China Sea (SCS) are inves- tigated with newly reprocessed satellite altimetry observations and hydrographic data. The eddy kinetic energy (EKE) level of basin-wide averages show a distinct seasonal cycle with the maximum in August-December and the minimum in February-May. Furthermore, the seasonal pattern of EKE in the basin is dominated by region offshore of central Vietnam (OCV), southwest of Taiwan Island (SWT), and southwest of Luzon (SWL), which are also the breeding grounds of mesoscale eddies in the SCS. Instability theory analysis suggests that the seasonal cycle of EKE is modulated by the baroclinic instability of the mean flow. High eddy growth rate (EGR) is found in the active eddy regions. Vertical velocity shear in the upper 50-500 m is crucial for the growth of baroclinic instability, leading to seasonal EKE evolution in the SCS. 展开更多
关键词 South China Sea eddy kinetic energy baroclinic instability vertical shear
下载PDF
Delayed baroclinic response of the Antarctic circum-polar current to surface wind stress 被引量:6
7
作者 YANG XiaoYi HUANG RuiXin +1 位作者 WANG Jia WANG DongXiao 《Science China Earth Sciences》 SCIE EI CAS 2008年第7期1036-1043,共8页
The Antarctic Circumpolar Current (ACC) responds to the surface windstress via two processes, i.e., the instant barotropic process and the delayed baroclinic process. This study focuses on the baroclinic instability m... The Antarctic Circumpolar Current (ACC) responds to the surface windstress via two processes, i.e., the instant barotropic process and the delayed baroclinic process. This study focuses on the baroclinic instability mechanism in ACC, which was less reported in the literatures. Results show that the strengthening of surface zonal windstress causes the enhanced tilting of the isopycnal surface, leading to more intense baroclinic instability. Simultaneously, the mesoscale eddies resulting from the baro- clinic instability facilitate the transformation of mean potential energy to eddy energy, which causes the remarkable decrease of the ACC volume transport with the 2-year lag time. This delayed negative cor- relation between the ACC transport and the zonal windstress may account for the steadiness of the ACC transport during last two decades. 展开更多
关键词 ANTARCTIC Circumpolar CURRENT ZONAL windstress baroclinic instability MESOSCALE EDDY
原文传递
A Further Investigation of the Decadal Variation of ENSO Characteristics with Instability Analysis 被引量:5
8
作者 孟祥凤 吴德星 +1 位作者 林霄沛 兰健 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2006年第1期156-164,共9页
Based on instability theory and some former studies, the Simple Ocean Data Assimilation (SODA) data are analyzed to further study the difference between the propagation of the ENSO-related oceanic anomaly in the off... Based on instability theory and some former studies, the Simple Ocean Data Assimilation (SODA) data are analyzed to further study the difference between the propagation of the ENSO-related oceanic anomaly in the off-equatorial North Pacific Ocean before and after 1976. The investigation shows that after 1976 in the off-equatorial North Pacific Ocean, there is a larger area where the necessary conditions for baroclinic and/or barotropic instability are satisfied, which may help oceanic anomaly signals propagating in the form of Rossby waves to absorb energy from the mean currents so that they can grow and intensify. The baroclinic energy conversion rate in the North Pacific after 1976 is much higher than before 1976, which indicates that the baroclinic instability has intensified since 1976. Prom another perspective, the instability analysis gives an explanation of the phenomena that the ENSO-related oceanic anomaly signal in the North Pacific has intensified since 1976. 展开更多
关键词 ENSO decadal variation North Pacific Ocean Rossby waves baroclinic instability barotropic instability
下载PDF
The intrinsic nonlinear multiscale interactions among the mean flow, low frequency variability and mesoscale eddies in the Kuroshio region 被引量:3
9
作者 Yang YANG X.San LIANG 《Science China Earth Sciences》 SCIE EI CAS CSCD 2019年第3期595-608,共14页
Using a new functional analysis tool, multiscale window transform(MWT), and the MWT-based localized multiscale energetics analysis and canonical transfer theory, this study reconstructs the Kuroshio system on three sc... Using a new functional analysis tool, multiscale window transform(MWT), and the MWT-based localized multiscale energetics analysis and canonical transfer theory, this study reconstructs the Kuroshio system on three scale windows, namely,the mean flow window, the interannual-scale(low-frequency) window, and the transient eddy window, and investigates the climatological characteristics of the intricate nonlinear interactions among these windows. Significant upscale energy transfer is observed east of Taiwan, where the mean Kuroshio current extracts kinetic energy from both the interannual and eddy windows.It is found that the canonical transfer from the interannual variability is an intrinsic source that drives the eddy activities in this region. The multiscale variabilities of the Kuroshio in the East China Sea(ECS) are mainly controlled by the interaction between the mean flow and the eddies.The mean flow undergoes mixed instabilities(i.e., both barotropic and baroclinic instabilities) in the southern ECS, while it is barotropically stable but baroclinically unstable to the north. The multiscale interactions are found to be most intense south of Japan, where strong mixed instabilities occur; both the canonical transfers from the mean flow and the interannual scale are important mechanisms to fuel the eddies. It is also found that the interannual-scale energy mainly comes from the barotropically unstable jet, rather than the upscale energy transfer from the high frequency eddies. 展开更多
关键词 KUROSHIO Multiscale window transform CANONICAL transfer Multiscale ENERGETICS analysis Multiscale interaction BAROTROPIC instability baroclinic instability
原文传递
Snowstorm over the Southwestern Coast of the Korean Peninsula Associated with the Development of Mesocyclone over the Yellow Sea 被引量:2
10
作者 Ki-Young HEO Kyung-Ja HA 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2008年第5期765-777,共13页
This study investigates the characteristics of a heavy snowfall event over the southwestern part of the Korean Peninsula on 4 December 2005. The snowstorm was a type of mesoscale maritime cyclone which resulted from b... This study investigates the characteristics of a heavy snowfall event over the southwestern part of the Korean Peninsula on 4 December 2005. The snowstorm was a type of mesoscale maritime cyclone which resulted from barotropic instability, and diabatic heating from the warm ocean in continental polar air masses. Based on surface observations, radiosonde soundings, MTSAT-1R satellite data and the 10-km grid RDAPS (Regional Assimilation and Prediction System based on the PSU/NCAR MM5) data, the evolution of the mesocyclone is explained by the following dynamics; (1) In the initial stage, the primary role in the cyclogenesis process of the mesocyclone is a barotropic instability in the horizontal shear zone. (2) In the developing stage, the mesocyclone moves and deepens into a baroclinic zone corresponding to the surface heating and moistening. (3) In the mature stage, it is found that the mesocyclone is intensified by the destabilization caused by enhanced low-level heating and condensation, the moisture flux convergence, and the interaction between upper and lower-level potential vorticity anomalies. We suggest that a checklist with stepwise indicators responsible for development be prepared for the forecasting of heavy snowfall over the southwestern part of the Korean Peninsula. 展开更多
关键词 heavy snowfall MESOCYCLONE baroclinic instability barotropic instability stepwise roles potential vorticity anomalies
下载PDF
Propagation of Envelope Solitons in Baroclinic Atmosphere 被引量:1
11
作者 谭本馗 尹东屏 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1995年第4期439-448,共10页
The propagation of finns amplitude baroclinic wave packets in the two-layer model is investigated by using the multiple-scale method.It is shown that the propagation of the wave packets can be described by the so-call... The propagation of finns amplitude baroclinic wave packets in the two-layer model is investigated by using the multiple-scale method.It is shown that the propagation of the wave packets can be described by the so-called unstable nonlinear Schrodinger equation which possesses envelope soliton solutions.The speeds of the solitons are independent of their amplitudes,while the width of the solitons is directly proportional to their speeds but inversely proportional to their amplitudes. 展开更多
关键词 Envelope solition baroclinic wave packet baroclinic instability
下载PDF
THE ANALYSIS OF INTRASEASONAL LONG ROSSBY WAVE SPEED IN THE SUBTROPICAL PACIFIC OCEAN 被引量:3
12
作者 LIN Xiao-pei WU De-xing LAN Jian 《Journal of Hydrodynamics》 SCIE EI CSCD 2006年第1期55-62,共8页
The analysis of the satellite altimeter data suggests that the propagating speed of intraseasonal long Rossby wave amplified in the subtropical Pacific Ocean is faster than that of first mode baroclinic free Rossby wa... The analysis of the satellite altimeter data suggests that the propagating speed of intraseasonal long Rossby wave amplified in the subtropical Pacific Ocean is faster than that of first mode baroclinic free Rossby wave predicted by the liner theory and the propagating speed of intrascasonal long Rossby wave reflected in the eastern boundary of Pacific Ocean agrees basically with the liner theory speed of first mode baroelinic free P, ossby wave. If we do not distinguish the two kinds of hmg Rossby waves and estimate the Rossby wave speed in the whole basin, the phase speed is merely 25% higher than the linear theory long Rossby wave speed. The acceleration of the propagating speed of intraseasonal long Rossby wave amplified in the subtropical Pacific Ocean is due to the existence of westward thermolcline mean flow. 展开更多
关键词 Rossby wave baroclinic instability critical frequency
原文传递
海温对月平均环流影响的数值试验 被引量:5
13
作者 李维京 张小礼 +1 位作者 李小泉 章基嘉 《应用气象学报》 CSCD 北大核心 1993年第A12期45-49,共5页
利用 T42L9全球谱模式,在相同初始场的条件下,将不同的 SST 作为外强迫源输入模式,其一个月延伸预报的结果表明,SST 的变化对第三旬的环流预报影响比较大,但对于不同的初值其影响是不同的,对于比较稳定的初值,不同的海温场对月平均环流... 利用 T42L9全球谱模式,在相同初始场的条件下,将不同的 SST 作为外强迫源输入模式,其一个月延伸预报的结果表明,SST 的变化对第三旬的环流预报影响比较大,但对于不同的初值其影响是不同的,对于比较稳定的初值,不同的海温场对月平均环流的影响较小;而对于不稳定的初始场,则影响较大.同时指出了500hPa 高度预报场的均方根误差的增长在中纬度主要与大气中的斜压不稳定有关,如果斜压不稳定度大,则误差随时间增长快;斜压不稳定度小,情况则相反. 展开更多
关键词 海洋 温度 大气环流 数值试验
下载PDF
Charney’s Model—the Renowned Prototype of Baroclinic Instability—Is Barotropically Unstable As Well 被引量:1
14
作者 Yuan-Bing ZHAO X.San LIANG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2019年第7期733-752,共20页
The Charney model is reexamined using a new mathematical tool, the multiscale window transform(MWT), and the MWT-based localized multiscale energetics analysis developed by Liang and Robinson to deal with realistic ge... The Charney model is reexamined using a new mathematical tool, the multiscale window transform(MWT), and the MWT-based localized multiscale energetics analysis developed by Liang and Robinson to deal with realistic geophysical fluid flow processes. Traditionally, though this model has been taken as a prototype of baroclinic instability, it actually undergoes a mixed one. While baroclinic instability explains the bottom-trapped feature of the perturbation, the second extreme center in the perturbation field can only be explained by a new barotropic instability when the Charney–Green number γ 1, which takes place throughout the fluid column, and is maximized at a height where its baroclinic counterpart stops functioning.The giving way of the baroclinic instability to a barotropic one at this height corresponds well to the rectification of the tilting found on the maps of perturbation velocity and pressure. Also established in this study is the relative importance of barotropic instability to baroclinic instability in terms of γ. When γ 1, barotropic instability is negligible and hence the system can be viewed as purely baroclinic;when γ 1, however, barotropic and baroclinic instabilities are of the same order;in fact, barotropic instability can be even stronger. The implication of these results has been discussed in linking them to real atmospheric processes. 展开更多
关键词 Charney’s MODEL multiscale window transform CANONICAL transfer baroclinic instability BAROTROPIC instability
下载PDF
北太平洋副热带逆流区涡旋动能谱的季节性变化及其机制 被引量:4
15
作者 李宏杰 徐永生 《海洋与湖沼》 CAS CSCD 北大核心 2017年第5期932-943,共12页
本文利用了23年的卫星高度计数据和WOA13气候态月平均温盐资料,考察了北太平洋副热带逆流(STCC)区涡旋动能谱及其涡旋尺度季节变化的动力过程。为了揭示其动力机制,本文采用了斜压2.5层模式并结合动能串级的理论进行分析。结果表明,在S... 本文利用了23年的卫星高度计数据和WOA13气候态月平均温盐资料,考察了北太平洋副热带逆流(STCC)区涡旋动能谱及其涡旋尺度季节变化的动力过程。为了揭示其动力机制,本文采用了斜压2.5层模式并结合动能串级的理论进行分析。结果表明,在STCC区由于海洋层结及地转流的垂向剪切发生了季节性变化,从而产生的斜压不稳定是导致涡旋动能谱季节变化的原因。涡旋动能最大的时间发生在5—6月份,滞后于斜压最不稳定发生的时间(3月份)约2—3个月左右,这是由于斜压不稳定产生的扰动需要一定时间才能发展成振幅足够大的涡旋。斜压不稳定提供的能量使得涡旋相互作用加强,产生了动能逆向串级,动能谱向更大尺度转移。涡旋能量尺度在3月份仅为280km,而在9月份达到最高值335km左右。另一方面,我们发现STCC区动能谱斜率及动能谱通量也有季节变化,在涡旋动能最大的5—6月份,当尺度小于罗斯贝变形尺度时,谱斜率达到1k–3,而动能谱通量达到最大值。对STCC区涡动能谱及涡旋尺度季节变化的研究,对深入认识中尺度涡旋的产生及其演变机制有着重要的意义。 展开更多
关键词 动能谱 能量尺度 斜压不稳定 逆向串级
下载PDF
Nonlinear Saturation of Baroclinic Instability in the Phillips Model: The Case of Energy 被引量:2
16
作者 项杰 孙立潭 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2002年第6期1079-1090,共12页
A conservation law for the Phillips model is derived. Using this law, the nonlinear saturation of purely baroclinic instability caused by the vertical velocity shear of the basic flow in the Phillips model—the case o... A conservation law for the Phillips model is derived. Using this law, the nonlinear saturation of purely baroclinic instability caused by the vertical velocity shear of the basic flow in the Phillips model—the case of energy—is studied within the context of Arnold’s second stability theorem. Analytic upper bounds on the energy of wavy disturbances are obtained. For one unstable region in the parameter plane, the result here is a second-order correction in &#949; to Shepherd’s; For another unstable region, the analytic upper bound on the energy of wavy disturbances offers an effective constraint on wavy (nonzonal) disturbances &#934;&#8242;<SUB> i </SUB>at any time. 展开更多
关键词 nonlinear saturation baroclinic instability Phillips model
下载PDF
Meso-scale available gravitational potential energy in the world oceans 被引量:2
17
作者 FENG Yang WANG Wei HUANG Ruixin 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2006年第5期1-13,共13页
The pitfalls of applying the commonly used definition of available gravitational potential energy (AGPE) to the world oceans are re-examined. It is proposed that such definition should apply to the meso-scale proble... The pitfalls of applying the commonly used definition of available gravitational potential energy (AGPE) to the world oceans are re-examined. It is proposed that such definition should apply to the meso-scale problems in the oceans, not the global scale. Based on WOA98 climatological data, the meso-scale AGPE in the world oceans is estimated. Unlike previous results by Oort et al. , the meso-scale AGPE is large wherever there is a strong horizontal density gradient. The distribution of meso-scale AGPE reveals the close connection between the baroclinic instability and the release of gravitational potential energy stored within the scale of Rossby deformation radius. 展开更多
关键词 energy of ocean circulation available potential gravitational energy MESO-SCALE baroclinic instability Rossby deformation radius
下载PDF
一次自上向下发展的高原涡的多尺度动力学分析 被引量:3
18
作者 容逸能 马继望 +1 位作者 李瑶婷 梁湘三 《气象科技进展》 2021年第1期7-18,共12页
高原涡作为经常给我国带来暴雨等灾害的天气系统,其形成一般认为是通过感热和潜热自下而上激发的,然而,2013年5月下旬发生的一次引发其下游灾害性强降水的高原涡却是由对流层高层天气尺度低涡诱发的。为此,基于新发展的多尺度子空间变... 高原涡作为经常给我国带来暴雨等灾害的天气系统,其形成一般认为是通过感热和潜热自下而上激发的,然而,2013年5月下旬发生的一次引发其下游灾害性强降水的高原涡却是由对流层高层天气尺度低涡诱发的。为此,基于新发展的多尺度子空间变换和多尺度能量涡度方法以及ERA5再分析资料对其动力学过程进行了详尽的探讨,先将原始场重构到三个尺度子空间,即背景环流尺度子空间、天气尺度子空间和高频尺度子空间,重构场上首次显示此次过程生成于青藏高原西北侧,其成因为对流层高层基本气流尺度向天气尺度的跨尺度动能正则传输,即正压失稳,并且表现为从高层向下。在发展阶段,其能量最终来源为基本气流向天气尺度的有效位能传输和非绝热加热,然而这些过程只发生于涡旋低层的西侧。进一步分析发现,天气尺度内存在一个能量再分配“路径”:首先,低层西侧获得的有效位能转换为动能,西侧垂直的气压梯度力做功将低层获得动能向高层分配;在高层,水平的气压梯度力做功进而将西侧获得的动能向东侧分配;东侧垂直的气压梯度力做功再将动能向低层分配;至此,低层西侧获得的能量被分配到整个涡旋空间中,使得涡旋能够均匀发展。 展开更多
关键词 高原涡 正则传输 多尺度子空间变换 正压不稳定 斜压不稳定
下载PDF
POM模式在日本南部黑潮路径变异研究中的应用 被引量:3
19
作者 邹广安 《海洋科学》 CAS CSCD 北大核心 2016年第2期151-158,共8页
日本南部黑潮路径变异对北太平洋地区的气候和环境具有显著的影响,对黑潮路径变异的研究具有重要的意义。本文利用POM(Princeton Ocean Model)数值模式模拟了日本南部黑潮的路径变异情况,分析了黑潮大弯曲路径形成的可能机制。研究结果... 日本南部黑潮路径变异对北太平洋地区的气候和环境具有显著的影响,对黑潮路径变异的研究具有重要的意义。本文利用POM(Princeton Ocean Model)数值模式模拟了日本南部黑潮的路径变异情况,分析了黑潮大弯曲路径形成的可能机制。研究结果表明,当黑潮处于非大弯曲路径时,相对位势涡度的平均值呈现递减趋势,说明日本南部低位势涡度水在不断积累,这样会使得四国再循环流的强度增强,迫使黑潮保持平直路径,同时,近岸黑潮垂直流速剪切增大,斜压不稳定性的作用也逐渐增大;当黑潮从非大弯曲路径向大弯曲路径过渡时,再循环流强度的减弱会导致黑潮的流速剪切减小。根据海表高度异常场以及海洋上层流场信息发现,近岸黑潮附近的气旋涡会随着再循环流区域反气旋涡的东侧向南运动,最终导致黑潮大弯曲的发生。分析涡流的能量,结果显示,黑潮大弯曲路径的形成与斜压不稳定性密切相关。 展开更多
关键词 黑潮路径变异 POM(Princeton OCEAN Model) 斜压不稳定性
下载PDF
ENSO循环的非对称性及其机制初步探讨 被引量:3
20
作者 于毅 孟祥凤 +1 位作者 张磊 赵杰臣 《热带海洋学报》 CAS CSCD 北大核心 2011年第4期31-37,共7页
利用SODA(Simple Ocean Data Assimilation)资料,以Nino3.4区SSTA(sea surface temperature anomaly)指数为标准,选取典型El Nio和La Nia事件进行合成分析,观察ENSO的非对称性。通过分析ENSO事件发生过程中温跃层深度异常和斜压能... 利用SODA(Simple Ocean Data Assimilation)资料,以Nino3.4区SSTA(sea surface temperature anomaly)指数为标准,选取典型El Nio和La Nia事件进行合成分析,观察ENSO的非对称性。通过分析ENSO事件发生过程中温跃层深度异常和斜压能量转化率的变化,研究其对ENSO循环非对称性的影响。由于与ENSO相关的海洋异常信号在南、北太平洋的传播主要是以Rossby波的形式,Rossby波可以通过不稳定机制获得能量成长和传播,斜压能量转化率越强,携带ENSO相关海洋异常信号的Rossby波就可能获得更多的能量成长,这种信号传播至赤道区域可以更快地导致ENSO事件的爆发。研究表明,在El Nio事件达到顶峰时,北太平洋ENSO相关的Rossby波传播区斜压不稳定能量很强(可使Rossby波增幅)、温跃层加深(可使Rossby波加速),有利于El Nio相关的暖信号传出,这很好地解释了El Nio事件总是比La Nia事件振幅大以及El Nio事件向La Nia事件转化比La Nia事件向El Nio事件转化快很多的现象。因为强斜压不稳定能量和加深的温跃层促使携带异常信号的Rossby波吸收能量成长和传播,这使得El Nio事件时东太平洋暖信号更容易西传,El Nio事件更快地衰退,并迅速向La Nia事件转化,这样可以解释ENSO循环的不对称现象。 展开更多
关键词 ENSO循环 非对称性 北太平洋 斜压不稳定
下载PDF
上一页 1 2 3 下一页 到第
使用帮助 返回顶部