The Comparison Of Cimp5 Models On Simulating The South Pacific Dipole

This paper uses the HadISST dataset of the Met Office Hadley Center from 1850 to 2005,the atmospheric dataset of NOAA(National Oceanic and Atmospheric Administration),and the model output data of 15 CMIP5(Coupled Model Intercomparison Project Phase 3)models,with SVD(singular vector decomposition),synthetic analysis and regression analysis.The temporal and spatial characteristics of the SPSD(South Pacific Subtropical Dipole)in historical observations and model simulations were studied and compared.Then it discusses the possible links between SPSD and ENSO(El Nino and South Oscillation).The main conclusions are as follows:(1)The spatial distribution of the first two main modes of the equatorial ENSO and the interpretation of the variance ratio are obtained by the EOF(Empirical Orthogonal Function)method,and then returned to the South Pacific region for deduction.The first major mode resulting from SVD decomposition of the region is SPSD.SST is reflected in the northeast region of the southwest region of the anti-phase of sea surface temperatures,showing a wider range of negative pressure centers on the sea surface pressure.The corresponding time development cycle starts in the southern hemisphere spring(September to November),matures in summer(December to February),and declines in autumn(March to May)(2)The analog pattern data CMIP5 15 performs the same processing,successfully simulated SPSD PSL(Pressure of Sea Level)and SST mode.The results show that ten models can simulate the complete SPSD generation process,and the main areas of SPSD are close to the observations,but the other five models have large differences in intensity,position and observation.(3)All models exhibit dipole mode one month before compare to the observation of the SPSD generation phase,and 1/3 models SST dipole anomaly can be traced back to six months;The spatial and temporal distribution of latent heat flux and SST show that latent heat flux is the main factor affecting the development of dipole mode.SPSD's change is mainly modulated by the atmospheric circulation.When SPSD develops strongest,there is a positive submerged latent heat flux abnormality above the positive pole of some modes,that is,the ocean transfers heat to the atmosphere.The analysis shows that the model's SST simulation intensity during simulating air-sea coupling process is stronger than the observation,and the PSL is close to the observation.