Question

how has oceanography from space using sensors on orbiting satellites and the development of new tools (e.g., AUVs, multi-beam sonar, among others) contributed to advancing our ability to map the seafloor, trace ocean currents, assess coastal erosion, determine levels of biological productivity, monitor El Nino, as well as reveal other oceanographic processes?

Answer 1

Ans-The space satellite which revolve around the globe are generally equipped with altimeter. Satellite altimeters measure sea surface height and other characteristics of the ocean surface, which are linked to underlying processes and structures. This makes the data useful for understanding the full depth of the global ocean, from the surface down to the sea floor. Before the introduction of these satellites the Measurement is done through buoys, ships, and tidal gauges whose distribution was limited to certain parts of the world.

These satellite are also equipped with microwave sensors, multi spectral and hyper spectral imaging, GPS and airborne light detection and ranging technology (LIDAR), which are used to monitor coastal erosion.

These satellite data is used to-

• Measure sea surface height-through which we can get the estimate about global warming.
• Understanding and modeling of hurricanes.
• Assist with the early detection, analysis, and monitoring of climate events such as the El Nino.
• Monitor coastal erosion.
• Long-term weather forecasting based on a better understanding of ocean-atmospheric coupling.
• measuring water vapor and atmospheric disturbances (through radiometer).

AUVs stands for-autonomous underwater vehicles which have the capabilities to map the seafloor with higher resolution than is possible with hull-mounted or towed sonar systems.

They are equipped with four mapping sonars that operate simultaneously.The multi beam sonar produces high-resolution bathymetry, the side scan sonars produce imagery based on the intensity of the sound energy’s reflections, and the subbottom profiler penetrates sediments on the seafloor, allowing the detection of layers within the sediments, faults, and depth to the basement rock.

They are also equipped with Acoustic Doppler Current Profiler which is commonly used to measure ocean currents,it use radio antennas and high frequency Radio Detecting and Ranging systems (radar) to measure surface ocean currents.

AUVs provide a faster, more reliable to produce very high-quality data sets especially in the deep ocean, and can accomplish this task efficiently and reliably.

These AUVs data is used to-

• Sediment transport from shelf to deep sea.
• Measure surface ocean currents.
• Identification and mapping of the important wildlife habitats.
• Enables targeted sampling.
• Help in planning & installing seafloor observatories.