Connection of sea level variability between the tropical western Pacific and the southern Indian Ocean during recent two decades

Based on the merged satellite altimeter data and in-situ observations, as well as a diagnosis of linear baroclinic Rossby wave solutions, this study analyzed the rapidly rise of sea level/sea surface height （SSH） in the tropical Pacific and Indian Oceans during recent two decades. Results show that the sea level rise signals in the tropical west Pacific and the southeast Indian Ocean are closely linked to each other through the pathways of oceanic waveguide within the Indonesian Seas in the form of thermocline adjustment. The sea level changes in the southeast Indian Ocean are strongly influenced by the low-frequency westward-propagating waves originated in the tropical Pacific, whereas those in the southwest Indian Ocean respond mainly to the local wind forcing. Analyses of the lead-lag correlation further reveal the different origins of interannual and interdecadal variabilities in the tropical Pacific. The interannual wave signals are dominated by the wind variability along the equatorial Pa- cific, which is associated with the El Nifio-Southern Oscillation; whereas the interdecadal signals are driven mainly by the wind curl off the equatorial Pacific, which is closely related to the Pacific Decadal Oscillation.

Interannual and Interdecadal Variations in Atmospheric Circulation Factors and Rainfall in China and Their Relationship

Wavelet analysis is used to study the interannual and interdecadal variationsof rainfall in China and atmospheric circulation factors, including the key atmosphericoscillations, W, C, E patterns and subtropical high. Regression analysis and correlation analysisare both used to study the relationship of atmospheric circulation factors and China rainfall ondifferent time scale and spatial scale. The results are as follows: (1) The variations ofatmospheric circulation and rainfall in China are characterized by interannual and interdecadalscales. The variations of atmospheric circulation and rainfall are composed of interannual andinterdecadal variations. It is necessary to separate those two time scales when climate changes andforecast are studied. (2) The variations of China rainfall are due to the interaction ofmulti-factors rather than single factors. The marked factors which influence the interannual andinterdecadal variations are various. Subtropical high is one of the marked factors which influenceinterannual variations of rainfall, while AO, NAO, and NPO are one of the marked factors whichinfluence interdecadal variations of rainfall. (3) The longer the time scale is, and the larger thespatial scale is, and the more remarkable the relationships between atmospheric circulation andrainfall are.