1959年来珠江三角洲地区的海平面变化与趋势

Changes and trends of sea level in the Pearl River Delta in the last 50 years

验潮站资料的低空间分辨率与卫星数据的短时序是区域海平面变化研究存在的关键难题。本文结合卫星高度计海平面高度距平资料及验潮站数据,基于EOF和最小二乘法重建过去53年(1959-2011年)珠江三角洲海平面变化时空序列,并利用主成分分析方法建立区域统一海平面变化时间序列。结果显示,基于EOF和最小二乘法的海平面高度场重建方法能很好地解决卫星高度计资料时间序列不长和验潮站分布稀缺时间不连续等问题,对于海平面变化研究,尤其是关于过去长期的变化过程及特征研究适用性良好。对统一海平面变化时间序列线性拟合显示,近53年珠江三角洲区域海平面平均变化速率为4.08 mm/yr,且存在近期加速上升趋势。与单站研究相比,该方法较好地表达了区域海平面主要变化特征并剔除可能存在的噪音。径流及厄尔尼诺现象也对珠江三角洲海平面空间变化产生影响。

Low spatial resolution of tide gauge records and shortness of satellite altimetry data are the main obstacles in studying regional long sea level change. The present study proposes a reconstruction of consistent regional sea level anomalies(CRSLA) in the Pearl River Delta over the period 1959-2011 by combining satellite altimetry dataset with tide gauge records using empirical orthogonal function(EOF) and principle components analysis method. The results indicate that the reconstruction method addresses issues such as the relative shortage of satellite altimetry data and the sparse and discontinuous nature of tide gauge records, demonstrating the applicability of this technique in investigation of long-term sea level change. Moreover, the rate of regional sea level rise obtained based on CRSLA(4.08 mm/yr) indicates acceleration over recent decades. Compared with the estimation from single tide gauge, the reconstruction explains the leading characteristics of regional sea level change with a low noise level. Both river flow and El Ni?o-Southern Oscillation events have considerable impacts on sea level variability in the Pearl River Delta.