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Rossby Whistle
The Rossby whistle is the oscillation of sea-level and bottom pressure in the Caribbean Sea with the period of 120 days and influenced by propagating westward oceanic Rossby wave. It is observed that a baroclinic Rossby wave propagating westward across the Caribbean Sea, oscillating with a period of 120 days, is rapidly returned to the east along the southern boundary as coastal shelf waves. The porous boundary of the Caribbean Sea results in this oscillation influencing a mass exchange with the wider ocean, leading to an almost uniform bottom pressure variability over the Grenada, Venezuela, and Colombia basins. These observations are based on satellite observation of the sea-level, monthly means of basin-averaged ocean bottom pressure using GRACE data, tide gauge measurements, and data from a bottom pressure recorder. The oscillation was first found in a numerical modelling simulation, from which is shown one cycle of the least squares fit of (left) sea level and (right) bottom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rossby Wave
Rossby waves, also known as planetary waves, are a type of inertial wave naturally occurring in rotating fluids. They were first identified by Sweden-born American meteorologist Carl-Gustaf Arvid Rossby in the Earth's atmosphere in 1939. They are observed in the atmospheres and oceans of Earth and other planets, owing to the rotation of Earth or of the planet involved. Atmospheric Rossby waves on Earth are giant meanders in high-altitude winds that have a major influence on weather. These waves are associated with pressure systems and the jet stream (especially around the polar vortices). Oceanic Rossby waves move along the thermocline: the boundary between the warm upper layer and the cold deeper part of the ocean. Rossby wave types Atmospheric waves Atmospheric Rossby waves result from the conservation of potential vorticity and are influenced by the Coriolis force and pressure gradient. The image on the left sketches fundamental principles of the wave, e.g., its restorin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caribbean Sea
The Caribbean Sea is a sea of the Atlantic Ocean, North Atlantic Ocean in the tropics of the Western Hemisphere, located south of the Gulf of Mexico and southwest of the Sargasso Sea. It is bounded by the Greater Antilles to the north from Cuba to Puerto Rico, the Lesser Antilles to the east from the Virgin Islands to Trinidad and Tobago, South America to the south from the Venezuela, Venezuelan coastline to the Colombia, Colombian coastline, and Central America and the Yucatán Peninsula to the west from Panama to Mexico. The Geopolitics, geopolitical region around the Caribbean Sea, including the numerous islands of the West Indies and adjacent coastal areas in the mainland of the Americas, is known as the Caribbean. The Caribbean Sea is one of the largest seas on Earth and has an area of about . The sea's deepest point is the Cayman Trough, between the Cayman Islands and Jamaica, at below sea level. The Caribbean coastline has many gulfs and bays: the Gulf of Gonâve, the Gul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency
Frequency is the number of occurrences of a repeating event per unit of time. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals (sound), radio waves, and light. The interval of time between events is called the period. It is the reciprocal of the frequency. For example, if a heart beats at a frequency of 120 times per minute (2 hertz), its period is one half of a second. Special definitions of frequency are used in certain contexts, such as the angular frequency in rotational or cyclical properties, when the rate of angular progress is measured. Spatial frequency is defined for properties that vary or cccur repeatedly in geometry or space. The unit of measurement of frequency in the International System of Units (SI) is the hertz, having the symbol Hz. Definitions and units For cyclical phenomena such as oscillations, waves, or for examp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellite Altimeter
Satellite geodesy is geodesy by means of artificial satellites—the measurement of the form and dimensions of Earth, the location of objects on its surface and the figure of the Earth's gravity field by means of artificial satellite techniques. It belongs to the broader field of space geodesy. Traditional geodetic astronomy, astronomical geodesy is ''not'' commonly considered a part of satellite geodesy, although there is considerable overlap between the techniques. The main goals of satellite geodesy are: # Determination of the figure of the Earth, positioning, and navigation (geometric satellite geodesy) # Determination of geoid, gravity of Earth, Earth's gravity field and its temporal variations (dynamical satellite geodesy or satellite physical geodesy) # Measurement of geodynamics, geodynamical phenomena, such as Crust (geology), crustal dynamics and polar motion Satellite geodetic data and methods can be applied to diverse fields such as navigation, hydrography, oceanogr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravity Recovery And Climate Experiment
The Gravity Recovery and Climate Experiment (GRACE) was a joint mission of NASA and the German Aerospace Center (DLR). Twin satellites took detailed measurements of Earth's gravity field anomalies from its launch in March 2002 to the end of its science mission in October 2017. The two satellites were sometimes called Tom and Jerry, a nod to the famous cartoon. The GRACE Follow-On (GRACE-FO) is a continuation of the mission on near-identical hardware, launched in May 2018. On March 19, 2024, NASA announced that the successor to GRACE-FO would be Gravity Recovery and Climate Experiment-Continuity (GRACE-C), to be launched in or after 2028. By measuring gravity anomalies, GRACE showed how mass is distributed around the planet and how it varies over time. Data from the GRACE satellites is an important tool for studying Earth's ocean, geology, and climate. GRACE was a collaborative endeavor involving the Center for Space Research at the University of Texas at Austin, NASA's Jet Pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tide Gauge
A tide gauge is a device for measuring the change in sea level relative to a vertical datum. It is also known as a mareograph, marigraph, and sea-level recorder. When applied to freshwater continental water body, water bodies, the instrument may also be called a limnimeter. Operation Sensors continuously record the height of the water level with respect to a height reference surface close to the geoid. Water enters the device by the bottom pipe (far end of the tube, see picture), and electronic sensors measure its height and send the data to a tiny computer. Historical data are available for about 1,450 stations worldwide, of which about 950 have provided updates to the global data center since January 2010. At some places records cover centuries, for example in Amsterdam where data dating back to 1700 is available. When it comes to estimating the greater ocean picture, new modern tide gauges can often be improved upon by using satellite data. Tide gauges are used to measure t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ocean General Circulation Model
Ocean general circulation models (OGCMs) are a particular kind of general circulation model to describe physical and thermodynamical processes in oceans. The oceanic general circulation is defined as the horizontal space scale and time scale larger than mesoscale (of order 100 km and 6 months). They depict oceans using a three-dimensional grid that include active thermodynamics and hence are most directly applicable to climate studies. They are the most advanced tools currently available for simulating the response of the global ocean system to increasing greenhouse gas concentrations. A hierarchy of OGCMs have been developed that include varying degrees of spatial coverage, resolution, geographical realism, process detail, etc. History The first generation of OGCMs assumed “rigid lid” to eliminate high-speed external gravity waves. According to CFL criteria without those fast waves, we can use a bigger time step, which is not so computationally expensive. But it also filt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Season
A season is a division of the year based on changes in weather, ecology, and the number of daylight hours in a given region. On Earth, seasons are the result of the axial parallelism of Earth's axial tilt, tilted orbit around the Sun. In temperate and polar regions, the seasons are marked by changes in the intensity of sunlight that reaches the Earth's surface, variations of which may cause animals to undergo hibernation or to Migration (ecology), migrate, and plants to be dormant. Various cultures define the number and nature of seasons based on regional variations, and as such there are a number of both modern and historical definitions of the seasons. The Northern Hemisphere experiences most direct sunlight during May, June, and July (thus the traditional celebration of Midsummer in June), as the hemisphere faces the Sun. For the Southern Hemisphere it is instead in November, December, and January. It is Earth's axial tilt that causes the Sun to be higher in the sky during the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whistle
A whistle is a musical instrument which produces sound from a stream of gas, most commonly air. It is a type of Fipple, fipple flute, and may be mouth-operated, or powered by air pressure, steam, or other means. Whistles vary in size from a small slide whistle or nose flute type to a large multi-piped Organ (music), church organ. Whistles have been around since early humans first carved out a gourd or branch and found they could make sound with it. In prehistoric Egypt, small shells were used as whistles. Many present day Wind instrument, wind instruments are inheritors of these early whistles. With the rise of more mechanical power, other forms of whistles have been developed. One characteristic of a whistle is that it creates a pure, or nearly pure, Musical tone, tone. The conversion of flow energy to sound comes from an interaction between a solid material and a fluid stream. The forces in some whistles are sufficient to set the solid material in motion. Classic examples a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clarinet
The clarinet is a Single-reed instrument, single-reed musical instrument in the woodwind family, with a nearly cylindrical bore (wind instruments), bore and a flared bell. Clarinets comprise a Family (musical instruments), family of instruments of differing sizes and pitches. The clarinet family is the largest woodwind family, ranging from the contrabass clarinet, BB♭ contrabass to the A-flat clarinet, A♭ piccolo. The B soprano clarinet is the most common type, and is the instrument usually indicated by the word "clarinet". German instrument maker Johann Christoph Denner is generally credited with inventing the clarinet sometime around 1700 by adding a register key to the chalumeau, an earlier single-reed instrument. Over time, additional keywork and airtight pads were added to improve the tone and playability. Today the clarinet is a standard fixture of the orchestra and concert band and is used in classical music, military bands, klezmer, jazz, and other styles. Etymol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sound
In physics, sound is a vibration that propagates as an acoustic wave through a transmission medium such as a gas, liquid or solid. In human physiology and psychology, sound is the ''reception'' of such waves and their ''perception'' by the brain. Only acoustic waves that have frequency, frequencies lying between about 20 Hz and 20 kHz, the audio frequency range, elicit an auditory percept in humans. In air at atmospheric pressure, these represent sound waves with wavelengths of to . Sound waves above 20 kHz are known as ultrasound and are not audible to humans. Sound waves below 20 Hz are known as infrasound. Different animal species have varying hearing ranges, allowing some to even hear ultrasounds. Definition Sound is defined as "(a) Oscillation in pressure, stress, particle displacement, particle velocity, etc., propagated in a medium with internal forces (e.g., elastic or viscous), or the superposition of such propagated oscillation. (b) Auditory sen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
