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The Tropical Intraseasonal Oscillation in SAMIL Coupled and Uncoupled General Circulation Models

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Advances in Atmospheric Sciences 2012年第3期29卷 529-543页

作者：杨静包庆王晓聪周天军 state Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal University state Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of Sciences

Simulations of tropical intraseasonal oscillation （TISO） in SAMIL, the Spectral Atmospheric Model from the Institute of Atmospheric Physics （IAP） state Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics （LASG） coupled and uncoupled general circulation models were comprehensively evaluated in this study. Compared to the uncoupled model, the atmosphere-ocean coupled model improved the TISO simulation in the following aspects：（1） the spectral intensity for the 30-80-day peak eastward periods was more realistic; （2） the eastward propagation signals over western Pacific were stronger; and （3） the variance distribution and stronger signals of Kelvin waves and mixed Rossby gravity waves were more realistic. Better performance in the coupled run was assumed to be associated with a better mean state and a more realistic relationship between precipitation and SST. In both the coupled and uncoupled runs, the unrealistic simulation of the eastward propagation over the equatorial Indian Ocean might have been associated with the biases of the precipitation mean state over the Indian Ocean, and the unrealistic split of maximum TISO precipitation variance over the Pacific might have corresponded to the exaggeration of the double Intertropical Convergence Zone （ITCZ） structure in precipitation mean state. However, whether a better mean state leads to better TISO activity remains questionable. Notably, the northward propagation over the Indian Ocean during summer was not improved in the mean lead-lag correlation analysis, but case studies have shown some strong cases to yield remarkably realistic northward propagation in coupled runs.

关键词： tropical intraseasonal oscillation atmosphere-ocean interaction mean state northward prop-agation simulation

Interdecadal Variations of ENSO around 1999/2000

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Journal of Meteorological Research 2017年第1期31卷 73-81页

作者： Zeng-Zhen HU Arun KUMAR Bohua HUANG Jieshun ZHU Hong-Li REN Climate Prediction Center NCEP/NWS/NOAA5830 University Research CourtCollege ParkMD 20740USA Department of Atmospheric Oceanic and Earth Sciences and Center for Ocean-Land-Atmosphere StudiesGeorge Mason University4400 University DriveFairfaxVA 22030USA Laboratory for Climate Studies&CMA-NJU Joint Laboratory for Climate Prediction Studies National Climate CenterChina Meteorological AdministrationBeijing 100081China

This paper discusses the interdecadal changes of the climate in the tropical Pacific with a focus on the correspond- ing changes in the characteristics of the E1 Nifio-Southern Oscillation （ENSO）. Compared with 1979-1999, the whole tropical Pacific climate system, including both the ocean and atmosphere, shifted to a lower variability regime after 1999/2000. meanwhile, the frequency of ENSO became less regular and was closer to a white noise process. The lead time of the equatorial Pacific＇s subsurface ocean heat content in preceding ENSO decreased remarkably, in addition to a reduction in the maximum correlation between them. The weakening of the correlation and the shorten- ing of the lead time pose more challenges for ENSO prediction, and is the likely reason behind the decrease in skill with respect to ENSO prediction after 2000. Coincident with the changes in tropical Pacific climate variability, the mean states of the atmospheric and oceanic components also experienced physically coherent changes. The warm an- omaly of SST in the western Pacific and cold anomaly in the eastern Pacific resulted in an increased zonal SST gradi- ent, linked to an enhancement in surface wind stress and strengthening of the Walker circulation, as well as an in- crease in the slope of the thermocline. These changes were consistent with an increase （a decrease） in precipitation and an enhancement （a suppression） of the deep convection in the western （eastern） equatorial Pacific. Possible con- nections between the mean state and ENSO variability and frequency changes in the tropical Pacific are also dis- cussed.

关键词： ENSO interdecadal variation amplitude suppression frequency change mean state

Impacts of Steering Flows with Different Timescales on the Track of Typhoon Sanba(2012)

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Journal of Meteorological Research 2021年第2期35卷 343-357页

作者： Qiao LIU Melinda PENG Weican ZHOU Tim LI Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)/Key Laboratory of Meteorological Disaster Ministry of Education(KLME)/Joint International Research Laboratory of Climate and Environmental Change(ILCEC)Nanjing University of Information Science&TechnologyNanjing 210044China University of Colorado Colorado SpringColorado 80918USA International Pacific Research Center and Department of Atmospheric Sciences School of Ocean and Earth Science and TechnologyUniversity of Hawaii at ManoaHonoluluHawaii 96822USA

Typhoon Sanba(2012),the strongest tropical cyclone(TC)of the year worldwide,moved northward almost along130°longitude during its lifetime and passed through different background flows from low to high *** steering flows with different timescales for Sanba are retrieved by using the NCEP reanalysis data with the total wind field separated into:a mean state,an interannual component,an intraseasonal component,and a synoptic *** analysis indicates that the intraseasonal timescale wave train(WT)with east–west oriented circulations made the largest contribution to the movement of *** effects of the environmental steering with different timescales on Sanba’s movement are investigated with numerical simulations using the Weather Research and Forecasting(WRF)*** the control simulation,total fields from the NCEP reanalysis are used as initial and boundary conditions,and the northward motion of Sanba is well *** sensitivity experiments,each of the intraseasonal and interannual components is removed one at a *** steering vectors associated with these timescales can explain their influences on the movement of Sanba in the *** budget analyses indicate that the horizontal vorticity advection made the largest contribution to the movement of the storm.

关键词： intraseasonal interannual mean state steering flow