Equatorial Indian Ocean Sea Surface Temperature Anomaly Heating Diagnostic Analysis And Numerical Experiments, The Impact Of Atmospheric Low Frequency Oscillation In High Latitudes

First a diagnostic analysis is carried out to research the frequency modulation effect that the El-Nino and La-Nina events has on atmospheric low-frequency oscillation (LFO) in the mid-high latitudes. The power spectral analysis is performed for daily 500hPa height field data in the mid-high latitudes of the northern hemisphere from 1950 to 1996.The results show that: (1) Intensity of low-frequency oscillation in winter is stronger than that in summer. (2) The main period of low-frequency oscillation has the shortened tendency during El-Nino events. (3) While in La-Nina years, the main period of low-frequency oscillation has the lengthened tendency. (4) In the year of El-Nino (La-Nina), the shortened (prolonged) main period of wave oscillation in summer is clearer than that in winter. (5) Either in the normal year or in the El-Nino (La-Nina) year, the main period of wave oscillation in summer or in winter on the 40?N is longer 5 days or so at least than that on the 60?N in the north hemisphere respectively.Then numerical experiments on forcing dissipation and heating response of dipole (unipole) are carried out using global spectral model of quasi-geostrophic barotropic vorticity equation. For every experiment model integration is run for 90 days on the condition of three waves quasi-resonance. The results are given as follows: (1) Under the effects of basic flow intensity and dipole (unipole) forcing source, there exist strong interaction among the three planetary waves, and there also exist quasi-two-week and intra-seasonal oscillation of the three planetary waves. (2) The stronger (weaker) the intensity of dipole or unipole forcing source and basic flow, the periods of LFO the shorter(longer). (3) The frequency modulation effects of positive (negative) dipole or unipole forcing source on LFO in the mid-high latitudes are difference. (4) The frequency modulation effects of positive dipole (unipole) forcing source on LFO is stronger than negative dipole (unipole), and the wave oscillation quicken evidently. (5) The frequency modulation effects of positive (negative) dipole and positive (negative) unipole forcing source on LFO have the samesensitive region. (6) The results of the stream function field of quasi-resonance three waves transforming with time evolving make sure further that the low-frequency oscillation exists in extratropical latitude, which has greater corresponding relationship with the wave oscillation obtained from the combination of the basic flow, the number of three waves and amplitude.At last, some theory analysis on wave quasi-resonance in forced and dissipative barotropic atmosphere is analysed in theoretics, which further proved the results of diagnosis and numerical experiments is understated.