What is underwater topography

NASA altimetry data are often combined with data from other ocean-viewing satellites and from in situ measurements taken from ships, profiling buoys and drifters.

These combined data sets are used to:. Ocean surface topography data have a wide spectrum of scientific applications. Ocean topography often corresponds to the amount of heat stored in the upper layers of the ocean. This information is useful in predicting hurricane season severity and forecasting individual storm severity.

Altimetry data also provide ctitical contributions to our knowledge of even longer-term phenomena such as global sea level rise.

Over the next few decades, scientists will continue to study these climate, weather and ocean circulation phenomena to better understand their impact on our environment and our daily lives. In addition to their value as a research tool, ocean surface topography data also have many practical and operational applications. They are used in ship routing, offshore oil operations, fisheries management, recreational boating, oil spill remediation, as well as search-and-rescue and naval maritime operations.

Ocean altimeter data have been used to help understand the behavior of Stellar sea lions and the migratory habits of hawksbill turtles and whales tracked by other satellites. The information ocean topography data provide on the extent and degree of ocean warming is important for coral reef research. There are also land applications of ocean altimetry data.

Near real-time data of the height of water in rivers and lakes is used for flood and drought investigations. Altimetry also provides a measurement of river level variations, which is especially useful in areas that are difficult to reach such as the Amazon River basin. Altimetry data also help to monitor Greenland ice sheet growth rates. The range from the satellite to the ocean surface is measured using an onboard altimeter that bounces microwave pulses off the ocean surface and measures the time it takes the pulses to return to the spacecraft.

The highly accurate altimeter range measurements are subtracted from the satellite orbital height, resulting in ocean height measurements relative to well-defined reference system. Ocean surface topography is estimated by referencing the sea surface height to the geoid. Other ancillary information on the ocean surface is also obtained from satellite altimetry including information on surface waves and roughness. The primary contribution of satellite altimetry to satellite oceanography has been to:.

Altimetry data are often combined with data from other ocean-observing satellites and from in situ measurements taken from ships, profiling floats and satellite-tracked drifting buoys. For example, these combined data sets are used to:. While this page does not contain any data, it provides succinct descriptions and pointers to the data via dataset information pages or online tools.

The information is broken up into multiple sections:. Google Tag Manager. Mailing List Forum PO. Science Disciplines. These sharply sloping sections are known as the Continental Slopes. They identify the border between the granite of the continent, and the basaltic crust of the ocean. Deep valleys have been observed in the Continental Slopes.

It is believed that these valleys have been created due to the earthquakes, or have been eroded by violent ocean currents. The divisions of the ocean water according to depth are known as Abyssal Zones. Each layer has its own characteristic features of pressure, temperature, salinity and biodiversity.

The deepest oceanic zone is the hadalpelagic zone that lies between 6,—11, meters. Radar altimeters have been developed for mapping ocean floor topography, including the valleys and hills of the ocean surface.

A microwave pulse is forwarded by these devices to the ocean surface, and time is measured for this signal to return. A microwave radiometer adjusts for any obstruction produced by the atmospheric water vapor. Other adjustments are also necessary because of the ionosphere electrons and the air in the atmosphere. The shape and strength of the return signal presents information regarding the speed of wind, and the height of ocean waves.

This data is utilized to determine the speed and direction of the oceanic currents. The variations in the global climate, and heat accumulated in the ocean are also measured.