台湾巴士海峡

台湾巴士海峡 The southern Taiwan Island bus channel connecting the Pacific Ocean with the South China Sea is an economic, military and political value of the "gold content" of the extremely high sea area, but also the Western Pacific Ocean is an important strategic significance. Due to the special geographical location, special natural geographical features, make it become the important military took control of the hub. And it has the characteristics of special marine hydrology and meteorology, which makes it a good submarine ambush operation area. The Bashi Channel between Taiwan island and the islands is about 185 km wide, with a depth of 2000-5000 meters, and a depth of 5126 meters. The Bahrain Tong channel is located between the Ba islands and Babuyan Islands. It is about 82 km wide, with a depth of 700-2000 meters and a depth of 2887 meters. Bashi Channel is located in Taiwan tectonic belt and the intersection of the Luzon arc tectonic belt, is a natural boundary between the Pacific and the South China sea. The seabed topography is very large, mainly between the continental slope, ridge trench, sill depth between 2400-2600 meters. The island of Luzon near the shelf 20-110 km wide, the southern tip of Taiwan Island shelf is very narrow, only about 20 kilometers. The surface sediments of the Bashi Channel are dominated by silty sand. The bus channel is located in the south of the Tropic of Capricorn. It is a tropical marine climate. The marine meteorological characteristics are characterized by high temperature and rainy weather, monsoon prevalence, thunderstorms, and frequent typhoons. Meteorological factors in the Bashi Channel monsoon and high frequency strong wind and big waves, so that the sea submarine a relatively advantageous position in the mutual antagonism and search of ships and aircraft in the. Launching sonar buoys is one of the important means of submarine searching for ships and aircraft. The surface flow of the sea water with high velocity will rapidly throw the air into the water, and the buoy will shift and take away, thus affecting the positioning accuracy of the submarine target. Sometimes the ocean currents also create the illusion that the stationary target coastal currents move in opposite directions. The Bashi Channel is one of the great waves in the Northwest pacific. Affected by the monsoon, with high frequency of strong wind and big waves. In the Northeast winter waves, 6 winds above 37.5%-40% high frequency, wave frequency 50%-60%, the frequencies of 70%, the average wave height are 2 meters (November and December more than 2.6-3.2 meters), the maximum wave height of 7-9.5 meters. Compared with winter, summer waves to some small channel (except during typhoon period), but there are still 20% frequency waves Chung and 30%-40%, the average wave height of 1.5 meters, the maximum up to 6-7 meters. High sea conditions will bring great difficulties to helicopter submarine search and antisubmarine warfare. When sea surface waves are very large, it is difficult for helicopters to take off and land on ships, and deep sonar and towed sonar are difficult to put down and recycle. The waves will greatly influence the detection performance of the sonar buoy, 3.04 meter high waves will cause loss of information transmission sonar buoy 75%, 4.57 meter high waves almost complete loss of information transmission sonar buoy. In addition, the thunderstorm and its surface breaking waves will increase the environmental noise in a large area of the sea, and reduce the signal-to-noise ratio of sonar receiver, thus reducing the recognition capability of the target. Submarine sonar in underwater activity is less affected by sea surface waves, so it has a comparative advantage in the adversarial search of surface ships and aircraft. The special sea conditions of the Bashi Channel have further expanded the advantages of the submarine. There is a small thermocline with a deeper depth, a deeper thickness and a longer and more stable depth in the Bashi Channel, which is beneficial to submarine communication and submarine covert operations. Thermocline is a water layer whose temperature, salinity, density, sound speed and other parameters vary greatly with depth. In the water layer is relatively stable in the ocean, the vertical distribution of water temperature, salinity, density, velocity and other state parameters is usually not gradual, under the mixed layer almost uniformly in the sea but a very thin, a step like change. In marine science, the sea water temperature, salinity, density, velocity state parameters such as a sharp change or not change series step like change layer, called the sea thermocline, halocline and pycnocline and thermocline velocity. Thermocline often exists in the ocean, and affects salinity, thermocline, thermocline and sonic thermocline. In general, the change of sea water density mainly depends on the change of temperature. In the sea area where the vertical gradient of sea salinity varies little, the thermocline of sea water is generally coincident with thermocline. Sea water has very poor conductivity to most radiation energy, and only acoustic energy is an exception. The average speed of sound transmission in water is about 1450 meters per second, which is about 4 times faster than that in air. Like in the air, any solid in water reflects sound waves, and reflected echoes can be detected by sensitive receivers. Unlike in the air, the speed of sound transmission in the sea depends on the temperature, pressure, and salinity of the sea, and its propagation path is not straight, but in the shape of an arc in accordance with Snell's law. Snell's law is the law of light propagation in air, but applies to the propagation of sound waves in water. According to Snell's law, acoustic refraction occurs when the density of water changes. That is to say, the sound wave in the water from a density layer to another layer of density propagation, the propagation path is curved: sound waves from the low density layer to high density layer propagation, refraction to the normal direction; on the contrary, the high density layer to the low density layer spread, to deviate from the normal direction refraction. In addition, the sea surface and the bottom of the sea also scatter the acoustic wave and appear the phenomenon of arc convergence, so that the sound wave emitted from a sound source can not pass through a certain sea area. The sea area is called the convergence zone, and the convergence zone has nothing to do with the intensity of the sound wave. Therefore, the submarine in the converging zone is difficult to detect even though it is very close to the sonar transmitter. During the Second World War, the submarine sunk warship battle, there are many is the convergence zone phenomenon. A sonic thermocline is a water layer whose sound propagation rate changes vertically in the vertical direction due to the uneven temperature, salinity, and pressure of the sea water. The propagation of sound waves in the ocean is not only related to the speed of sound, but also to the vertical gradient of sound velocity. In the upper layer, the influence of water temperature change is the biggest. As the water temperature drops sharply, the sound speed decreases sharply and reaches the minimum value at the thermocline, which is called the vocal tract axis (also called deep sound channel). In the deep sea below the thermocline, the vertical variation of temperature tends to be smooth, and the sound speed increases with the increase of pressure. In the channel under the axial velocity gradient in the opposite direction, the acoustic sound velocity in the line where the largest bending to the thermocline channel axis, the sound produced two results: one is the propagation in the water acoustic signal is not easy through the thermocline; two is the low attenuation of sound signals in deep channel in the distance can be far away (especially the low frequency acoustic wave), generally in the 1000 km above. Sonic thermocline plays an active role in submarine communication and submarine concealment. Underwater acoustic equipment works best in deep channels, and submarines operating in deep channels can detect targets far away. Sonar signals launched above the sonic thermocline are difficult to detect under the thermocline, and submarines that are submerged below the thermocline are less likely to be detected. Affected by the tropical monsoon climate and special hydrological and geographical factors, the Bashi Channel seawater temperature and salinity is divided into vertical structure of the Kuroshio surface water, subtropical subsurface water, middle water, deep water and bottom water in five distinct water masses. There is a small bus channel with strength, upper bound depth (50-150 m), thickness (50-150 m), for a long time deep seawater pycnocline stable, very conducive to submarine communication and avoid water and air search submarine covert action. The sea pycnocline Bashi Channel can produce "liquid seabed" effect of submarine, the submarine to ambush and covert attack. The thermocline of sea water is of great use to the control of submarine. The thermocline is generally stable and can effectively prevent the underwater convection of the sea water. In the upper and lower density density is the density gradient in the thermocline, the water buoyancy, commonly known as "liquid sea"; in the upper density, lower density small negative density gradient in the thermocline, the water buoyancy decreases, known as the "sea cliff interrupt". The density gradient is a stable positive thermocline can make relatively static rotation of submarine floating in the thermocline water, can regulate their buoyancy in the "sea cruise liquid" slow "mute", which is not easy to be found, like the lion slowly approaching the antelope, on the other side of unconscious condition, and close to the target search sure, the rapid implementation of the interception range, attacks on surface ships and hidden hunter, quickly out of combat attack. Affected by climate, monsoon, Kuroshio and other factors, the surface water temperature of the Bashi Channel is higher all the year round, generally at 25-29 degrees Celsius, and the seasonal variation is not large (winter 24-27 degrees, summer 28-30 degrees Celsius). The North East Strait INKUROSHIO water depth of 50-150 meters, affected by the changes in the Bashi Channel surface temperature gradient from the surface to 100 meters deep temperature change is very small, up to 200 meters deep water temperature began to change significantly (14-20 C), the temperature gradient increases with the depth of change. The thermocline of the Bashi Channel persists all the year round and is stable and lasting. The surface salinity of the Bashi Channel is smaller, with 34.5 in winter and 34.1 in summer. Due to the high salinity of the Kuroshio, the salinity gradient is very small. With deep sea type standard, the sea water density layer of the Bashi Channel is a positive thermocline, mainly with thermocline. It exists all the year round and is stable and lasting. The bus channel has a clear blue color and a greater transparency, The general trend is that the summer is high and the winter is low; the eastern part is high and the west is low; the south is high and the north is low. From February to October, the sea water transparency was greater than 30 meters; the sea water transparency was 24-26 meters from November to January of next year. The Bashi Channel high transparency seawater although have certain influence on the submarine stealth, but by the depth of moderate (upper bound depth 50-1 50 meters), large thickness (50-150 meters), stable seawater pycnocline formed "liquid and seabed" dominant meteorological communication conditions, can largely compensate for the high sea due to the transparency of submarine activities. Wide narrow Bashi Channel "submarine submarine liquid" slow "mute" cruise provided a good space, the bus channel and the great depth and large range of common components and northeastern Dongsha waters water, provides a broad space for the submarine tactical maneuver and attack