Self-affine gravity covariance model for the Bay of Bengal

Abstract

SUMMARY An anisotropic covariance model embedded with self-affine characteristics of gravity and bathymetry anomalies is proposed. High-resolution free air gravity data obtained from the high-density satellite altimetry data have been used to study the self-affinity of the gravity measurements. The digital terrain model—5 (DTM-5) is used for the bathymetry data. The Hurst coefficients (H) are calculated using 2-D power spectral density of the free air gravity and bathymetry data from 140 blocks of 1 ◦ × 1 ◦ . The Hurst coefficients (H) are also determined for free air gravity data along 24 orthogonal profiles using rescaled range (R/S) analysis. Further, the estimated H values are used in order to find the appropriate gravity and bathymetry covariance model for the area. The average value of H is more for 2-D free air gravity data as compared with the bathymetry data. The H values from the 1-D free air gravity profiles are found to be 0.75 and 0.77 along the N‐S and E‐W directions, respectively. The Von Karman covariance model with different correlation lengths is found to be suitable for 2-D and 1-D free air gravity and 2-D bathymetry data.