The Characteristic Of Northwest Pacific Sea Level Variation, And Influencing Factor

By selecting Northwest Pacific125long-term tide gauge stations, the results showing that the overall long-term trend of the125tide gauge stations is rising, after revising by the use of GIA (Glacial Isostatic Adjustment), the average rate of change turned out to be2.5mm/year. According to the characteristicsof the geography of the region, the region is divided into three zones to analyze, the Near-shore Area (including the South China Sea, East China Sea, Yellow Sea, Bohai Sea, the Sea of Japan), Coastal Area (including the coast of theeast side of Japanese island, Taiwan, Okinawa, the coast of Philippines), Oceanic Area(Pacific open sea).The power spectrum analysis turned out that the general tide gauge sea level change cycle is1year, the annual cycle strength crescendo with increasinglatitude from the Oceanic Area to the Near-shore Area, the strongest site of the annual cycle is in the Near-shore Area of Chinese Bohai. The semi-annualcycle mainly exists in low latitude area and Hokkaido area of Japan, the semi-annual cycle strength from Oceanic Area to the Near-shore Area crescendo. The inter-annual cycle intensity is more intense in the low latitudes than in highlatitudes.The characteristic of distribution of sea-level seasonal variation amplituderesembles a cycle. The general trend in the seasonal variation of amplitude andphase of the T/P observation data and the steric height seasonal change in amplitude and phase is the same, but the spatial differences of the T/P sea level are comparatively larger, while the spatial changes of steric height is smaller.The impact upon the sites of tropical regions of by the ENSO is far greater than high-latitude sites. The inter-decadal variations amplitude of ocean coastal zone is comparatively larger than the sites on the same latitude. Inter-decadal variations amplitude is decreasing with the increasing of latitude, while thecycle length is increasing. The more affected sites by PDO are mainly concentrated in the inshore areas of Japanese island and junction of oceanic coastal zo ne.There are advancing and lagging phenomenon in tide gauge SLA with ENSO and PDO.The more affected sites by ENSO are mainly concentrated in the tropics,and mainly presents in the SLA lags SOI signal within1-3months. The mainrelation of SLA and SOI of the sites in Near-shore Area and the Coastal Areais lagging; The SLA and SOI sites of Oceanic Area are generally in synchronization.In the South China Sea, Yellow Sea, Korean Peninsula,35°N south ofthe Japanese island, most of the relations with SOI of the sites are leading.35°N north the Near-shore Area of Japan, Bohai Sea, the East China Sea siteSLA and PDO relations are mostly lagging. Coastal Area of the site SLA andPDO relations are lagging. The region of north of35°N site is mainly in PDO synchronization. The performance is un-uniform monthly distribution, showing the zonal distribution along the latitude. The relationship between SLA of the Oceanic Area stations and PDO is mainly lagging.Finally, using Markov model, simulate the of South China Sea, the localwind stress, Ekman dynamic height.