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Effect of low-frequency rossby wave on thermal structure of the upper southwestern tropical Indian Ocean

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Chinese Journal of Oceanology and Limnology 2010年第2期28卷 344-353页

作者：冯俊乔白学志陈永利胡敦欣 Institute of Oceanology Chinese Academy of Sciences Key Laboratory of Ocean Circulation and waves Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences

We investigate the influence of low-frequency rossby waves on the thermal structure of the upper southwestern tropical Indian Ocean (SWTIO) using Argo profiles, satellite altimetric data, sea surface temperature, wind field data and the theory of linear vertical normal mode decomposition. Our results show that the SWTIO is generally dominated by the first baroclinic mode motion. As strong downwelling rossby waves reach the SWTIO, the contribution of the second baroclinic mode motion in this region can be increased mainly because of the reduction in the vertical stratification of the upper layer above thermocline, and the enhancement in the vertical stratification of the lower layer under thermocline also contributes to it. The vertical displacement of each isothermal is enlarged and the thermal structure of the upper level is modulated, which is indicative of strong vertical mixing. However, the cold rossby waves increase the vertical stratification of the upper level, restricting the variability related to the second baroclinic mode. On the other hand, during decaying phase of warm rossby waves, Ekman upwelling and advection processes associated with the surface cyclonic wind circulation can restrain the downwelling processes, carrying the relatively colder water to the near-surface, which results in an out-of-phase phenomenon between sea surface temperature anomaly (SSTA) and sea surface height anomaly (SSHA) in the SWTIO.

关键词： rossby wave vertical baroclinic mode Argo sea surface height anomaly (SSHA) sea surfacetemperature anomaly (SSTA)

The Impact of Mid- and High-Latitude rossby wave Activities on the Medium-Range Evolution of the EAP Pattern During the Pre-Rainy Period of South China

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Acta meteorologica Sinica 2009年第3期23卷 300-314页

作者：施宁布和朝鲁纪立人王盘兴 College of Atmospheric Sciences Nanjing University of Information Science and Technology Center for Disastrous Climate Research and Prediction Institute of Atmospheric PhysicsChinese Academy of Sciences State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences

Based on the NCEP DOE AMIP II daily reanalysis data （1979-2005）, the evolution of the East Asia/Pacific （EAP） teleconnection pattern during the pre-rainy period of South China is studied on the medium-range time scale. It is found that positive and negative EAP patterns share a similar generation process. In the middle and upper troposphere, rossby wave packets emanating from the northeast Atlantic or Europe propagate toward East Asia along the Eurasian continent waveguide and finally give rise to the three anomaly centers of the EAP pattern over East Asia. Among the three anomaly centers, the western Pacific subtropical center appears the latest. rossby wave packets propagate from the high latitude anomaly center toward the mid-latitude and the subtropical ones. The enhancement and maintenance of the subtropical anomaly center is closely associated with the subtropical jet waveguide and the incoming rossby wave packets from the upstream. In the lower troposphere, rossby wave packets emanate from the subtropical Asia toward East Asia. Positive and negative EAP patterns could not be regarded as ＂mirrors＂ to each other with simply reversed phase. For the positive pattern, the positive height anomaly center around the Scandinavia Peninsula keeps its strength and position during the mature period, and the rossby wave packets thus propagate persistently toward East Asia, facilitating a longer mature time of the positive pattern. As for the formation of the negative EAP pattern, however, the incoming rossby wave energy from the upstream contributes to both the enhancement and southeastward movement of the negative anomaly belt from the Yenisei River to the Bering Strait and the positive anomaly center around Mongolia. At the peak time, the two anomlous circulations are evolved into the Northeast Asia and the mid-latitude anomaly centers of the negative pattern, respectively. The energy dispersion of rossby wave packets is relatively fast due to the predominant zonal circ

关键词： rossby wave medium range process EAP (East Asia/Pacific) pattern pre-rainy period of South China precipitation

Topography and the Non-linear rossby wave in the Zonal Shear Basic Flow

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Advances in Atmospheric Sciences 1993年第2期10卷 233-242页

作者：何建中 Nanjing Institute of Meteorology Nanjing

Under semi-geostropical approximation, by means of phase angle function the non-linear ordinary differential equation is derived involving topography and zonal shear basic flow. Conditions for the existence of limited amplitude periodical and isolated wave solutions are directly obtained based on the qualitative theory of the ordinary differential equation. Analysis is thus made of the influence of topography and zonal shear flow on the existence of wave solution. Finally, explicit wave solutions are determined by function approaching with the result that topography and zonal shear flow affect not only the existence but also the form of waves, indicating the non-linear features of waves and the effect of topography and shear basic flow on undulation.

关键词： wave Solution rossby wave Eastern Slope Western Slope Phase Orbit

Topographically Forced rossby wave Instability and the Development of Blocking in the Atmosphere

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Advances in Atmospheric Sciences 1990年第4期7卷 433-440页

作者： Luo Dehai Chengdu Institute of Meteorology 610041Sichuan Provincen

In this paper, the linear stability of disturbance superimposed on basic state rossby wave forced by topography is investigated, and pointed out that when a certain criterion is satisfied by the basic flow and the height of topography for the subresonance, the small disturbance may be unstable. Furthermore, we also compare the evolution of the instability disturbance with the development of blocking in the Pacific, and we suggested that the topographically forced rossby wave instability may provide a possible mechanism for the development of blocking in the Pacific.

关键词： rossby wave Planetary wave Diabatic Heating Baroclinic Instability Atmospheric Blocking

Alignment of Track Oscillations during Tropical Cyclone Rapid Intensification

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Advances in Atmospheric Sciences 2024年第4期41卷 655-670页

作者： Tong XIE Liguang WU Yecheng FENG Jinghua YU Key Laboratory of Meteorological Disaster of Ministry of Education Nanjing University of Information Science and TechnologyNanjing 210044China Dept.of Atmospheric and Oceanic Sciences and Institute of Atmospheric Sciences Fudan UniversityShanghai 200438China CMA-FDU Joint Laboratory of Marine Meteorology Shanghai 200438China

Recent studies on tropical cyclone(TC)intensity change indicate that the development of a vertically aligned TC circulation is a key feature of its rapid intensification(RI),however,understanding how vortex alignment occurs remains a challenging topic in TC intensity change *** on the simulation outputs of North Atlantic Hurricane Wilma(2005)and western North Pacific Typhoon Rammasun(2014),vortex track oscillations at different vertical levels and their associated role in vortex alignment are examined to improve our understanding of the vortex alignment during RI of TCs with initial hurricane *** is found that vortex tracks at different vertical levels oscillate consistently in speed and direction during the RI of the two simulated *** the consistent track oscillation reduces the oscillation tilt during RI,the reduction of vortex tilt results mainly from the mean track before *** is also found that the vortex tilt is primarily due to the mean vortex track before and after *** track oscillations are closely associated with wavenumber-1 vortex rossby waves that are dominant wavenumber-1 circulations in the TC inner-core *** study suggests that the dynamics of the wavenumber-1 vortex rossby waves play an important role in the regulation of the physical processes associated with the track oscillation and vertical alignment of TCs.

关键词： tropical cyclone rapid intensification vortex tilt rossby wave

The interaction between zonal flow and rossby waves with scalar nonlinearity

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Chinese Physics B 2014年第6期23卷 357-360页

作者：张喜平赵强 School of Physics Peking University

The nonlinear interactions between zonal flow and rossby waves are studied by numerical simulations with focus on the effects of scalar nonlinearity. The numerical results show that the scalar nonlinearity has an appr... 详细信息

关键词： rossby wave sheared zonal flow dipole scalar nonlinearity

High-Resolution Modeling Study of the Kuroshio Path Variations South of Japan

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Advances in Atmospheric Sciences 2014年第5期31卷 1233-1244页

作者： LI Rui ZHANG Zuowei WU Lixin Physical Oceanography Laboratory/Qingdao Collaborative Innovation Center of Marine Science and Technology Ocean University of China

A high-resolution ocean general circulation model （OGCM） is used to investigate the Kuroshio path variations south of Japan. The model reproduces many important features of the Kuroshio system including its interannual bimodal variability south of Japan. A decreasing trend of the spatial averaged relative vorticity is detected when the Kuroshio takes the non-large meander （NLM） path, and during the transition period from the NLM to the large meander （LM）, a sudden release of velocity shear corresponds well to the weakening of the Shikoku recirculation gyre （SRG）, which plays a key role in modulating the Kuroshio path variations. Analysis of eddy energetics indicates that baroclinic instability is mainly responsible for the formation of the LM. In addition, further analysis shows that the strength of the SRG could be largely influenced by the baroclinic rossby wave adjustment process, forced by the wind stress curl anomalies in the North Pacific basin, based on the model investigation. It is suggested that the cyclonic disturbances might account for the weakening of the SRG, and act as a remote trigger for the baroclinic instability of the Kuroshio south of Japan.

关键词： OGCM Kuroshio path variations large meander rossby wave

Understanding Interannual Variations of the Local Rainy Season over the Southwest Indian Ocean

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Advances in Atmospheric Sciences 2021年第11期38卷 1852-1862页

作者： Hanying LI Peng HU Qiong ZHANG Ashish SINHA Hai CHENG Institute of Global Environmental Change Xi'an Jiaotong UniversityXi'an 710054China Center for Monsoon ystem Research Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100190China Department of Physical Geography and Bolin Centre for Climate Research Stockholm UniversityStockholm SE 10691Sweden Department of Earth Science California State UniversityDominguez HillsCarson CA 90747USA Department of Earth Sciences University of MinnesotaMinneapolis MN 55455USA

Located at the southern boundary of the tropical rainfall belt within the South Africa monsoon regime,Rodrigues Island,~2500 km east of East Africa,is ideally located to investigate climatic changes over the southwest Indian Ocean(SWIO).In this study,we investigate the climatic controls of its modern interannual rainfall variability in terms of teleconnection and local *** find that increased rainfall over the SWIO tends to occur in association with anomalously warm(cold)SSTs over the equatorial central Pacific(Maritime Continent),resembling the central Pacific El Niño,closely linked with the Victoria mode in the North *** analyses show that the low-level convergence induced by warm SST over the equatorial central Pacific leads to anomalous low-level divergence over the Maritime Continent and convergence over a large area surrounding the Rodrigues Island,which leads to increased rainfall over the SWIO during the rainy ***,the excited rossby wave along the tropical Indian Ocean transports more water vapor from the tropical convergence zone into the SWIO via intensified northwest ***,positive feedback induced by the rossby wave response to the increased rainfall in the region contributes to the large interannual variations over the SWIO.

关键词： southwest Indian Ocean interannual rainfall variability Pacific Walker Circulation rossby wave positive feedback

Decadal Shift in the Relationship between Winter Arctic Oscillation and Central Indian Ocean Precipitation during the Early 2000s

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Journal of Meteorological Research 2021年第5期35卷 857-867页

作者： Yiwen SHI Yi CHEN Daoyi GONG Key Laboratory of Environmental Change and Natural Disaster of Ministry of Education Beijing Normal UniversityBeijing 100875 Academy of Disaster Reduction and Emergency Management Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875 State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing 100875

The present study investigated the long-term change in the interannual relationship between the boreal winter Arctic Oscillation(AO)and tropical Indian Ocean(TIO)climate during 1979-2019 and found that their linkage experienced a decadal change in 2001/*** 19-yr sliding correlation coefficient between the January-February-March(JFM)AO index and central TIO(0-10°S,65°-80°E)precipitation was significant,with values of approximately 0.50-0.75 during 1979-2001,but abruptly decreased to 0.35 in 2002 and 0.10 in ***,the spatial patterns of the AO-related atmospheric circulation anomalies also displayed different features before and after *** 2002-2019,the anomalous anticyclone in the middle troposphere over the Arabian Sea moved northwestward and strengthened,and the JFM AO was more closely correlated to the anticyclone,with correlation coefficient changed from-0.38 before 2001 to-0.63 after 2001;correspondingly,strong cross-equator air flows were observed over the western TIO(40°-50°E),but no significant anomalies of precipitation in the central TIO were *** 1979-2001,however,significant southward cross-equator air flows appeared over the central TIO(65°-75°E),which enhanced the intertropical convergence zone and upward air motions,leading to more precipitation in central *** analysis shows that the AO may modulate the Arabian anticyclone through two rossby wave paths in the upper troposphere:a midlatitude(50°-60°N)path during 1979-2001 from North Atlantic southeastward to the Middle East and the neighboring Arabian Sea;and a subtropical(20°-30°N)path during 2002-2019 from North Atlantic eastward to the Middle East and Arabian *** wave activity fluxes induced by AO were concentrated along the two paths before and after 2001,and the location of the cross-equator flows depends on the location of the *** of the decadal changes in the AO-associated wave trains need further investigation.

关键词： winter Arctic Oscillation tropical Indian Ocean precipitation rossby wave