New 3-D Acoustic Seafloor Imaging System with High Resolution Successfully Developed

The impact of oil leakage to the ocean every year due to improper lay-down of oil pipes on the seafloor as a result of measurement inaccuracy is far greater than that caused by wreck oil tankers.

The existing sounding scanning sonar system has two major shortcomings: first, its accuracy for locations right under it is poor; second, it can not work when two or more echo waves reflect from two different directions onto the sonar array simultaneously. These factors seriously affect the operation distance, measurement accuracy, efficiency and applicability of the sonar. A new 3-D acoustic seafloor imaging system with high resolution has been developed by Prof. Weiqing ZHU, Institute of Acoustics (IOA), CAS, who successfully tackles the above problems of the conventional sonar with a technical breakthrough. The project has recently passed the Achievement Appraisal organized by the Chinese Academy of Sciences. Experts agreed in concord that the system is "a large-sized sonar that can acquire both the bathymetric and the geomorphological maps, and one of the few systems in the world that can measure microrelief. The IOA is the first to develop the prototype of a high-resolution depth-finding scanning sonar that has been successfully used by underwater robots, and whose indexes have reached the world's leading level at the end of the 20th century."

So far, the system has filed four patent applications, including a foreign one.

Satellite Altimetry in China Achieves Important Headway

The Application of Satellite Altimetry in the Environment of Inshore Geophysics and Marine Dynamics in China is a key project sponsored by the National Natural Science Foundation of China undertaken by the Wuhan Institute of Topography and Geophysics, CAS, it has passed the approval test conducted by an expert panel.

The sea bottom contour processed with the satellite altimetry has a higher resolution and accuracy than the ETOP05 data widely adopted by the international community. It displays more clearly the seabed relief, tectonic features and dynamic events in China seas and neighboring waters. The Institute has developed proprietary software for processing hypsometric data from different satellites, improved the iterative cutting method for hypsometry-gravity problems, and proposed a land-sea gravity field model of Chinese mainland and offing, whose gravity abnormality and model accuracy are equivalent to the international leading level by using the pseudo-conciliatory gravity field demonstration.