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A THREE-DIMENSIONAL COASTAL barotropic MODEL IN GENERALIZED CURVILINEAR GRIDS

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Chinese Journal of Oceanology and Limnology 1999年第4期17卷 289-299页

作者：鲍献文孙文心史峰岩

The method of automatically generating generalized curvilinear meshes has many advantages and is beginning to be used in ocean simulations. This three dimensional (3 D) coastal barotropic model in generalized curvilinear grids was developed to simulate the M 2, S 2, K 1 and O 1 tidal waves in the Bohai Sea, China. The numerical results agreeing with observations showed that the method is an effective tool for improving accuracy of simulations in shallow shelf seas, especially in the near coast region, if the pseudo effect there usually caused by rectangular grids can be removed.

关键词： three dimensions barotropic model curvilinear grids Bohai Sea

A barotropic QUASI-GEOSTROPHIC MODEL WITH LARGE-SCALE TOPOGRAPHY, FRICTION AND HEATING

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Journal of Tropical Meteorology 2000年第1期6卷 65-74页

作者：蒋循陈炯刘式适 Department of Geophysics Peking University Beijing 100871 China

Based on the barotropic equations including large-scale topography, friction and heat factor, a barotropic quasi-geostrophic model with large-scale topography, friction and heating is obtained by means of scale analysis and small parameter method. It is shown that this equation is a basic one, which is used to study the influence of the Tibetan Plateau on the large-scale flow in the atmosphere. If the friction and heating effect of large-scale topography are neglected, this model will degenerate to the general barotropic quasi-geostrophic one.

关键词： scale analysis small parameter method linearization barotropic quasi-geostrophic model

THE DIABATIC WAVES IN barotropic MODEL

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Journal of Tropical Meteorology 2000年第1期6卷 1-14页

作者：李黎明黄大川乔方利刘式适 Department Of Geophysics Peking University Beijing 100871 China First National Institute of Oceanography Key Laboratory of Marine Science and Numerical Modeling Qingdao 266000 China

The equations of barotropic model are used to discuss the effects of diabatic factors such as heat-ing of convective condensation, evaporation-wind feedback and CISK on the Rossby wave and the Kelvin wave. In low latitudes we have obtained the angular frequency and analyzed the period and stability of waves. The result shows the existence of the diabatic factors not only enlarges the period of adiabatic waves but also changes the stability of waves. Thus we think that the so-called intraseasonal oscillation and some other low-frequency oscillations are a kind of diabatic waves which are important factors producing the long-term weather changes and short-term climatic evolution.

关键词： low-frequency oscillation diabatic wave barotropic model

DEVELOPMENT OF A TROPICAL CYCLONE IN barotropic ENVIRONMENTAL FLOWS

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Journal of Tropical Meteorology 1996年第2期2卷 148-154页

作者：李小凡

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ＤＥＶＥＬＯＰＭＥＮＴＯＦＡＴＲＯＰＩＣＡＬＣＹＣＬＯＮＥＩＮＢＡＲＯＴＲＯＰＩＣＥＮＶＩＲＯＮＭＥＮＴＡＬＦＬＯＷＳＬｉＸｉａｏｆａｎ（李小凡）（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｔｅｏｒｏｌｏｇｙ，ＵｎｉｖｅｒｓｉｔｙｏｆＨａｗａｉｉａｔＭａｎｏａ，Ｈ...

关键词： barotropic environmental flows tropical cyclone kinetic energy conversion relative vorticity gradient.

Charney’s Model—the Renowned Prototype of Baroclinic Instability—Is barotropically Unstable As Well

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Advances in Atmospheric Sciences 2019年第7期36卷 733-752页

作者： Yuan-Bing ZHAO X.San LIANG School of Atmospheric Sciences Nanjing University of Information Science and TechnologyNanjing210044China School of Marine Sciences Nanjing University of Information Science and TechnologyNanjing210044China School of Mathematics and Statistics Nanjing University of Information Science and TechnologyNanjing210044China

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 *** 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.

关键词： Charney’s model multiscale window transform canonical transfer baroclinic instability barotropic instability

Nonlinearity and Finite-Time Instability in a T21L3 Quasigeostrophic Model

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Acta meteorologica Sinica 2011年第4期25卷 419-429页

作者：姜智娜王东海 State Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences

In this paper, a nonlinear optimization method is used to explore the finite-time instability of the atmospheric circulation with a three-level quasigeostrophic model under the framework of the conditional nonlinear optimal perturbation （CNOP）. As a natural generalization of linear singular vector （SV）, CNOP is defined as an initial perturbation that makes the cost function the maximum at a prescribed forecast time under certain physical constraint conditions. Special attentions are paid to the different structures and energy evolutions of the optimal perturbations. The results show that the most instable region of the global atmospheric circulation lies in the midlatitude Eurasian continent. More specially, SV and CNOP in the total energy norm with an optimization time of 2 days both present localness： they are mainly located in the midlatitude Asian continent and its east coast. With extension of the optimization time, SVs are more upstream and less localized in the zonal direction, and CNOPs differ essentially from SVs with broader zonal and meridional coverages; as a result, CNOPs acquire larger kinetic and available potential energy amplifications than SVs in the nonlinear model at the corresponding optimization time. For the climatological wintertime flow, it is seen that the baroclinic terms remain small over the entire time evolution, and the energy production comes essentially from the eddy kinetic energy, which is induced by the horizontal shear of the basic flow. In addition, the effects of SVs and CNOPs on the Eurasian atmospheric circulation are explored. The results show that the weather systems over the Eurasian continent in the perturbed fields by CNOPs are stronger than those by SVs at the optimization time. This reveals that the CNOP method is better in evaluating the instability of the atmospheric circulation while the SV method underestimates the possibility of extreme weather events.

关键词： nonlinearity finite-time instability barotropic baroclinic

The intrinsic nonlinear multiscale interactions among the mean flow, low frequency variability and mesoscale eddies in the Kuroshio region

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Science China Earth Sciences 2019年第3期62卷 595-608页

作者： Yang YANG X.San LIANG School of Marine Sciences Nanjing University of Information Science and Technology School of Atmospheric Sciences Nanjing University of Information Science and Technology

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 *** 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 *** 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.

关键词： Kuroshio Multiscale window transform Canonical transfer Multiscale energetics analysis Multiscale interaction barotropic instability Baroclinic instability

Temperature variability caused by internal tides in the coastal waters of east coast of Peninsular Malaysia

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Acta Oceanologica Sinica 2019年第1期38卷 22-31页

作者： Nur Hidayah Roseli Mohd Fadzil Akhir Institute of Oceanography and Environment Universiti Malaysia Terengganu

The effects of tidal currents(i.e., barotropic and internal tides) are important in the biogeochemistry of a coastal shelf sea. The high-frequency of currents and near-bottom temperatures collected in three consecutive southwest monsoon seasons(May, June, July and August of 2013 until 2015) is presented to reveal the role of the tidal currents to the temperature variability in the coastal shelf sea of the east coast of Peninsular Malaysia(ECPM),south of the South China Sea(SCS). The results of a spectral density and harmonic analysis demonstrate that the near-bottom temperature variability and the tidal currents are influenced by diurnal(O_1 and K_1) and semidiurnal(M_2) tidal currents. The spectral density of residual currents(detided data) at 5, 10 and 16 m depth also shows significant peaks at the diurnal tidal frequency(K_1) and small peaks at the semidiurnal tidal frequency(M_2)indicating the existence of internal tides. The result of the horizontal kinetic energy(HKE) shows a strong intermittent energy of internal tides in the ECPM with the strongest energy is found at 16 m depth during a sporadic cooling event in June and July. A high horizontal cross-shore heat flux(16 m) also indicates strong intrusions of cooler water into the ECPM in June and July. During the short duration of cold pulse water observed in June and July, a cross-wavelet analysis also reveals the strong relationship between the near-bottom temperatures and the internal tidal currents at the diurnal tidal frequency. The intrusion of this cooler water is probably related to the monsoon-induced upwelling in June. It is loosely interpreted that the interaction between the strong barotropic tides and the steep slope in the central basin of the SCS under the stratified condition in southwest monsoon has generated these internal tides. The dissipation of internal tides from the slope area probably has driven the cold-upwelled water into the ECPM coastal shelf sea when the upwelling intensity is th

关键词： east coast of Peninsular Malaysia South China Sea barotropic tidal currents internal tides nearbottom temperature coastal shelf sea

Dynamic Features and Maintenance Mechanism of Asian Summer Monsoon Subsystem

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Advances in Atmospheric Sciences 1999年第4期16卷 523-536页

作者：徐建军吴国雄 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics ( LASG) Institute of Atmspheric Physics Chinese Academy of Sciences Beijing

In the context of the dissociation of vertical shear flow and tropospheric mean flow based on 1980-1996 NCEP/ NCAR re-analysis, study is undertaken of the barotropic and baroclinic development characteristics and kinetic energy maintenance mechanisms of Asian summer monsoon. Evidence suggests that the monsoon activity is marked by noticeable baroclinicity in three active regions of different dynamical characteristics, located in India, East Asian tropics and subtropics, respectively, with greatly differing maintenance mechanisms of barotropic / baroclinic kinetic energy.

关键词： Monsoon barotropic Baroclinic Maintenance