Study Of Spatial And Temporal Characteristics Variation Of South China Sea Wave

The spatial and temporal characteristics of South China Sea (SCS) wave during the period of1979-2012have been investigated based on the European Centre for Medium-Range Weather Forecasts interim reanalysis (ERA-Interim) dataset, and we focused on the variations in the boreal winter (1979/80-2011/12). The results show that the leading mode of sinificant wave height anomalies (SWHA) over the SCS exhibits significant interannual variations and a decadal shfit around the mid-1990s, and features a basin wide pattern over the entire SCS with a center located in the west of Luzon Strait. The decadal change from a weak regime to a strong regime is mainly associated with the enhancement of winter monsoon modulated by the Pacific Decadal Oscillation (PDO). The interannual variations of SWHA is well negative correlated with the El Nino Southern Oscillation (ENSO) in the simultaneous season and the preceding autumn. For a better understanding of the physical mechism between SCS ocean waves and ENSO, further investigation is made by analyzing atmospheric circulation. The impact of ENSO on SWHA over SCS is bridged by the East Asian winter monsoon and Pacific-East Asian teleconnection in the lower troposphere. During El Nino (La Nina), the anomalous Philippine Sea anticyclone (cyclone) are dominate over the Western North Pacific, helps to weaken (enhance) East Asian winter monsoon and then emerges (negative) positive SWHA over SCS.The numerical simulation of waves is an important part of the study of ocean waves, which has been developed and being more mature in recent years. In the last section of the thesis, the wave fields in south China sea during2008have been simulated by Wave Watch Ⅲ in this thesis, and the high resolution mixed wind field data of QSCAT/NCEP was used as the input wind of the third generation wave numerical model (Wave Watch Ⅲ). The output of the model can generally reflect the variability characteristics of the south China sea wave field. Further analysis show that the simulation result have a good correlation with the input wind, by improving the accuracy of wind field can perfect the simulated results.