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海面高度变化包含了周期性的潮位变化和非周期性的风场、气压和涌浪等过程引起的增、减水变化,较大幅度的增、减水都可能引发自然灾害.本文利用东海海底观测网小衢山试验站获取的长期连续观测资料,通过功率谱及潮汐调和分析方法计算了试验站海平面变化的主周期及其分量值,并由海平面观测值减去潮汐调和分析值得到海面高度异常值(sla).研究海域sla值与南北向风速有较好的相关性,相关系数为0.65,并通过线性拟合得出由局地风场引起的海面高度异常值slawind.slawind是sla的主要分量,但非等值,即由sla-slawind得到剩余海面高度异常值slaresidual不等于零,表明有其他引发海平面异常变化的外力因素存在.通过详细分析2010年2月27日智利8.8级强震发生前后一段时间的海平面变化数据,发现在2010年2月28日15:00时slaresidual达到极大值0.48m,恰好与太平洋海啸中心预报的智利地震海啸进入东中国海沿岸的时间相一致,由此判断该剩余海面高度异常受到了智利地震海啸的影响.这是我国第一次用海底观测网的连续、实时数据详细分析越洋地震海啸在我国近海海域的增水过程、极值及其出现时刻,这对于海啸预报模型的验证与改进和对计划中在东海海域建设海底观测网和海洋灾害预警等均有重要意义.
Changes in sea level include periodic tidal range changes and aperiodic wind field, pressure and surge caused by the increase and decrease of water changes, more substantial increase, reduce water may lead to natural disasters.In this paper, the East China Sea The long-term continuous observation data obtained from Xiaoqushan experimental station in the observation network were used to calculate the main period and its component value of the sea level change at the test station by power spectrum and tidal harmonic analysis. The tidal harmonic analysis value was deducted from the sea level observation The sea surface slab has a good correlation with the north-south wind speed, the correlation coefficient is 0.65, and the sea surface anomaly value caused by the local wind field is obtained through the linear fitting slawind.slawind The main component of sla but non-equivalence, ie, the slaresidual of the remaining sea level anomaly slaresidual obtained by sla-slawind is not equal to zero, indicating that there are other external forces that cause abnormal changes in the sea level. By analyzing in detail February 27, 2010 Chile 8.8 Data on sea level changes over a period of time before and after the strong earthquakes found that the slaresidual reached a maximum of 0.48 m at 15:00 on February 28, 2010, exactly in line with the forecast of the Pacific Tsunami Center Chile earthquake tsunami into the East China Sea coast consistent time, to determine the residual sea level anomalies affected by the Chilean earthquake and tsunami.This is the first time we use continuous and real-time data from the ocean floor observation network detailed analysis of the overseas earthquake tsunami In China’s offshore waters, the process of increasing water, its extreme value and its emergence moment are of great significance for the verification and improvement of the tsunami forecast model and for the planning of early warning of oceanic disasters in the East China Sea.