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Intraseasonal variability of the equatorial pacific Ocean and its relationship with ENSO based on Self-Organizing Maps analysis

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Journal of Oceanology and Limnology 2020年第4期38卷 1108-1122页

作者： FENG Junqiao WANG Fujun WANG Qingye HU Dunxin Institute of Oceanology Chinese Academy of SciencesQingdao 266071China Key Laboratory of Ocean Circulation and Waves Chinese Academy of SciencesQingdao 266071China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China Function Laboratory for Ocean Dynamics and Climate Qingdao National Laboratory for Marine Science and TechnologyQingdao 266237China

We investigated the intraseasonal variability of equatorial pacific subsurface temperature and its relationship with El Nino-Southern Oscillation(ENSO) using Self-Organizing Maps(SOM) analysis.Variation in intraseasonal subsurface temperature is mainly found along the thermocline.The SOM patterns concentrate in basin-wide seesaw or sandwich structures along an east-west axis.Both the seesaw and sandwich SOM patterns oscillate with periods of 55 to 90 days,with the sequence of them showing features of equatorial intraseasonal Kelvin wave,and have marked interannual variations in their occurrence frequencies.Further examination shows that the interannual variability of the SOM patterns is closely related to ENSO;and maxima in composite interannual variability of the SOM patterns are located in the central pacific during CP El Nino and in the eastern pacific during EP El Nino.The se results imply that some of the ENSO forcing is manife sted through changes in the occurrence frequency of intraseasonal patterns,in which the change of the intraseasonal Kelvin wave plays an important role.

关键词： intraseasonal variability equatorial pacific El Niño-Southern Oscillation(ENSO) Self-Organizing Maps(SOM)

Sensitivity of the Upper Ocean Temperature and Circulation in the equatorial pacific to Solar Radiation Penetration Due to Phytoplankton

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Advances in Atmospheric Sciences 2007年第5期24卷 765-780页

作者：林鹏飞刘海龙张学洪 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric Physics(IAP) Chinese Academy of Sciences(CAS)Beijing 100029 Graduate University of the Chinese Academy of SciencesBeijing 100039 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric Physics(IAP) Chinese Academy of Sciences(CAS)Beijing 100029

Solar radiation penetration in the upper ocean is strongly modulated by phytoplankton, which impacts the upper ocean temperature structure, especially in the regions abundant with phytoplankton. In the paper, a new solar radiation penetration scheme, based on the concentration of chlorophyll-a, was introduced into the LASG/IAP （State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics/Institute of Atmospheric Physics） Climate system Ocean Model （LICOM）. By comparing the simulations using this new scheme with those using the old scheme that included the constant e-folding attenuation depths in LICOM, it was found that the sea surface temperature （SST） and circulation in the central and eastern equatorial pacific were both sensitive to the amount of phytoplankton present. Distinct from other regions, the increase of chlorophyll-a concentration would lead to SST decrease in the central and eastern equatorial pacific. The higher chlorophyll-a concentration at the equator in comparison to the off-equator regions can enlarge the subsurface temperature gradient, which in turn strengthens the upper current near the equator and induces an enhancing upwelling. The enhancing upwelling can then lead to a decrease in the SST in the central and eastern equatorial pacific. The results of these two sensitive experiments testify to the fact that the meridional gradient in the chlorophyll-a concentration can result in an enhancement in the upper current and a decrease in the SST, along with the observation that a high chlorophyll-a concentration at the equator is one of the predominant reasons leading to a decrease in the SST. This study points out that these results can be qualitatively different simply because of the choice of the solar radiation penetration schemes for comparison. This can help explain previously reported contradictory conclusions.

关键词： SST solar radiation penetration equatorial pacific upwelling Chlorophyll-a

An extended variable-grid global ocean circulation model and its preliminary results of the equatorial pacific circulation

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Acta Oceanologica Sinica 2004年第1期23卷 23-29页

作者： FANGGuohong WEIZexun WANGYonggang CHENHaiying WANGXinyi KeyLaboratoryofMarineScienceandNumericalModelling FirstInstituteofOceanographyStateOceanicAdministrationQingdao266061China InstituteofOceanology ChineseAcademyofSciencesQingdao266071China GraduateSchoolofChineseAcademyofSciences Beijing100039China

To investigate the interaction between the tropical pacific and China seas a variable-grid global ocean circulation model with fine grid covering the area from 20°S to 50°N and from 99° to 150°E is developed. Numerical computation of the annually cyclic circulation fields is performed. The results of the annual mean zonal currents and deep to abyssal western boundary currents in the equatorial pacific Ocean are reported. The North equatorial Current,the North equatorial Countercurrent, the South equatorial Current and the equatorial Undercurrent are fairly well simulated. The model well reproduces the northward flowing abyssal western boundary current.From the model results a lower deep western boundary current east of the Bismarck-Solomon-New Hebrides Island chain at depths around 2 000 m has been found. The model results also show that the currents in the equatorial pacific Ocean have multi-layer structures both in zonal currents and western boundary currents, indicating that the global ocean overturning thermohaline circulation appears of multi-layer pattern.

关键词： global ocean circulation model variable grid equatorial pacific zonal currents lower deep western boundary current abyssal western boundary current

Study　on　the　characteristics　of　the　marine　boundary　layer　in　the　equatorial　pacific

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Acta Oceanologica Sinica 1994年第2期13卷 225-236页

作者： Zhang Ziyu and Zhou Mingyu

In this paper the variations of the wind, temperature,humidity and turbulence in the atmospheric boundary layer over the tropical ocean are analysed by use of observational data with tethersonde over the equatorial pacific of 165°E from November 17, 1989 to June 29, 1990. According to the analyses, it is pointed out that generally the thermodynamic structure of the Marine boundary layer in the tropical ocean area remains in a state of convective boundary layer owing to higher temperature of the sea water. Generally, the cumulus generated by local convection easts in the mixed layer, and the cloud top is the top of the mixed layer. The turbulent kinetic energy in the surface layer (less 0. 4 Zi)and in the capping inversion layer is in exceedingly unbalanced state.

关键词： equatorial pacific marine boundary layer turbulent kinetic energy

equatorial TRAPPED WAVES IN THE MEAN STATE WITH SLOW VARIATION:INHOMOGENOUS equatorial DUCT

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Journal of Hydrodynamics 2004年第2期16卷 182-185页

作者： HANWei HUANGSi-xun InstituteofMeteorology P.L.A.UniversityofscienceandEngineeringNanjing211101Chinae-mail：huangsxp@yahoo***

The effects of zonally varying mean state of equatorial pacific on planetaryequatorial trapped waves were analytically investigated. A WKB approximation was used with the slowzonal variation hypothesis, acceptable in the context of equatorial trapped low-frequencyvariability, and a working space transformation was made to turn the meridional trappedlow-frequency variability, and a working space transformation was made to turn the meridional modeequation into the Weber-Hermite equation in the new space. The inhomoge-neous equatorial wave ductwas proposed and the theoretical results were compared with observation. It matches the real stateof the equatorial pacific to a certain degree.

关键词： equatorial pacific equatorial trapped waves inhowogenous equatorial duct

ENSO Amplitude Change in Observation and Coupled Models

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Advances in Atmospheric Sciences 2008年第3期25卷 361-366页

作者：张琼关月杨海军 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG)Institute of Atmospheric Physics Chinese Academy of Sciences Department of Atmospheric Science School of PhysicsPeking UniversityBeijing 100871

Observations show that the tropical E1 Nifio-Southern Oscillation （ENSO） variability, after removing both the long term trend and decadal change of the background climate, has been enhanced by as much as 60% during the past 50 years. This shift in ENSO amplitude can be related to mean state changes in global climate. Past global warming has caused a weakening of the Walker circulation over the equatorial Indo-pacific oceans, as well as a weakening of the trade winds and a reduction in the equatorial upwelling. These changes in tropical climatology play as stabilizing factors of the tropical coupling system. However, the shallower and strengthening thermocline in the equatorial pacific increases the SST sensitivity to thermocline and wind stress variabilities and tend to destabilize the tropical coupling system. Observations suggest that the destabilizing factors, such as the strengthening thermocline, may have overwhelmed the stabilizing effects of the atmosphere, and played a deterministic role in the enhanced ENSO variability, at least during the past half century. This is different from the recent assessment of IPCC-AR4 coupled models.

关键词： ENSO variability global warming thermocline equatorial pacific