Earth observing satellite systems are deployed to survey the changes and variations of all factors on the Earth surface including the ocean. This is the useful tool that allows us to sight and observe our beautiful world from space comprehensively. Without remote sensing instruments, it becomes more difficult for us to study anything in large spatial scales. In particular, physical oceanographic factors require the research from comprehensive to detail and their influence on other biological or chemical factors in ocean as well as on the climate and weather phenomena.
There are many kinds of remote sensing instruments which are utilized in study the oceans, involving satellites that have the stable orbits in outer space around the Earth, airbornes and UAV (Unmanned Aerial Vehicle) platforms which their orbits can be changed in every measurement. All these devices use the thermal infrared and microwave scanning sensors that use electromagnetic radiation to view the ocean. Each kind of sensor has different strengths and weakness. Therefore they are applied properly to receive the highest efficient data. Thermal infrared sensors allow scientists to collect the images with high accuracy and good spatial resolutions but they are strongly impacted by clouds, aerosol. However, the microwave scanning sensors enable to measure throughout clouds but their images has low accuracy and spatial resolution. Some physical factors of the oceans require the long-term and continuous measurements because they are large temporal and spatial scale factors such as thermohaline circulation, ocean currents, the sea surface temperature (SST),.. Remote sensing technique is applied to track the change of each factor. These data can be used to provide accurate predictions in the future tens or even hundreds of years and assist scientists give the hindcasts in the past concurrently.
For example, the data of the different variation level in SST allow oceanographers give the predictions for the information of the natural phenomena in the oceans such as fronts, eddies, the change in ocean circulations, the weather conditions in a short time or the percentage of the formation and the extensity of storms, cyclones in the ocean. Moreover, this information also helps fishers find the good fishing ground where has the upwelling phenomenon.
Not only SST, this technique also is utilized for the observations of the ocean color, the water quality, the bathymetry, sea-surface roughness, tide, the wind and wave conditions in the ocean as well as other environment factors. Furthermore, through the analysis of remote sensing images, the researchers can determine which type of wave formed and its characteristics including the direction in the spread process. From there, the possible influences can be predicted and warned such as Tsunami which may cause the considerable disasters. Besides that, the bathymetry information from satellites can be added in the bed topography data measured from the maritime ships or vessels to create the fully work-out marine topography map.
The satellites and other remote sensing instruments help monitor physical factors and other concerned factors in oceans. The ocean color and the water quality can be evaluated by analyzing the concentration of suspended sediment or the variations of SST from the satellite images. The result can indicate the pollution level and the causes of the pollution such as the thermal pollution from nuclear power plant which is usually constructed near the seas as well as the waste pollution from the industrial parks.
Nowadays, this technology is more and more employed in several different fields by scientists around the world and becoming a technique which cannot lack in studying and monitoring our natural world.