基于重力梯度的模拟退火法反演中国南海海底地形

The inversion of seabed terrain of the South China Sea by simulated annealing based on gravity gradient data

模拟退火法是一种全局寻优算法,在地球物理反演中得到广泛应用.本文应用快速模拟退火法对中国南海海域的重力垂直梯度进行反演来获得中国南海高分辨率海底地形,首先推导出密度界面与重力垂直梯度的对应关系,然后利用理论模型试验证明快速模拟退火法能成功地根据重力垂直梯度来计算密度界面的变化,最后将其应用于由Geosat,ERS-1/2,T/P,Jason-1,EnviSat-1卫星测高数据计算得到的中国南海海域重力垂直梯度异常,反演得到的中国南海海底地形与LDEO船测海深相接近,两者之间差的最大值为0.24 km.

Simulated annealing （SA） is a global optimization algorithm, and it is widely used in geophysical inversion. In this paper, we apply the fast simulated annealing （FSA） method to the gravity gradient data of the South China Sea area to obtain the high-resolution submarine topography. First, we derive the corresponding relationship of density interface and gravity gradient, and then we demonstrate that the FSA method can obtain the density interface depending on the gravity vertical gradient data successfully. At last, we apply the proposed method to the gravity gradient data of South China Sea calculated by the satellite elevation data of Geosat, ERS-1/2,T/P,Jason-1,EnviSat-1, and the inverted seabed terrain is close to the measured depth by LDEO, the maximum difference is 0.24 km.