- Settore: Education
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Founded in 1876, Texas A&M University is a U.S. public and comprehensive university offering a wide variety of academic programs far beyond its original label of agricultural and mechanical trainings. It is one of the few institutions holding triple federal designations as a land-, sea- and ...
A method for analyzing transient tracer data where a time dependent box model is used to simulate the inventory or mean concentration of a tracer in a prescribed reservoir. The model is driven by the time dependent surface water concentration and parameters representing exchange times or volume transports are determined by fitting the model to observations.
Industry:Earth science
An instrument used to monitor oceanic fronts since Rossby (1969) first introduced the concept of using variations in acoustic travel time to measure changes in the depth of the main thermocline. They were initially deployed in the MODE project and have been used extensively in many other regions. The use of an IES requires calibration of travel time measurements into other scientific quantities of interest, with calibration requiring knowledge of the variations in temperature and salinity stratification and the resulting density and sound speed profiles in the region where the IES is to be deployed.
Industry:Earth science
The hypothesis that iron plays a major regulatory role in phytoplankton productivity. While the potential role of iron as a limiting factor in phytoplankton productivity was appreciated by researchers as early as the 1930s, it wasn't until John Martin convincingly pieced together several lines of evidence in the late 1980s that the oceanographic community gave notice to the point of planning major experiments to test it. The threads of Martin's argument included that:
* the primary source of iron to the surface waters of the oceans is from the land;
* the dissolved iron concentrations in offshore areas are extremely low, i.e. two orders of magnitude less than thought by the investigators in the 1930s;
* atmospheric dust deposition in the two major high nutrient, low chlorophyll (HNLC) areas of the oceans - the Antarctic and equatorial Pacific Oceans - are the lowest in the world; and
* laboratory experiments in which bottles filled with surface waters from NHLC regions and incubated at simulated in situ light and temperature for about a week showed that iron-enriched bottles always ended up with higher total chlorophyll that the control bottles without iron.
Industry:Earth science
In geophysical fluid dynamics this refers to fluid motion in which there is no vorticity.
Industry:Earth science
The replacement of the z coordinate in an x-y-z coordinate system with the potential temperature. This can be done when horizontal scales are large compared to vertical scales, i.e. when the hydrostatic approximation can be made.
Industry:Earth science
A theoretical wind component originating from the spatial non-uniformity of local rates of change of pressure.
Industry:Earth science
A contour line on a weather map that signifies the location of equal changes of pressure over a specified period.
Industry:Earth science
A horizontal pressure force averaged in longitude and time over a material surface of constant potential density. This is associated with a combinatino of transient (mesoscale) and standing (time-mean, longitudinally varying) eddies.
Industry:Earth science
A scheme to systematize the classification of the hydrography of the oceans developed by Montgomery in the late 1930s. He developed this to overcome limitations he saw in the earlier core layer method of Wust. In this method variable properties (e.g. salinity, temperature, etc.) are examined on surfaces of constant potential density along which it is assumed that maximum mixing and flow occur. The variations in depth of such surfaces can also be used as a diagnostic tool for locating geostrophic currents since rapid changes in depth are indicative of their presence.
The isopycnal method was originally applied such that all densities were calculated relative to the ocean surface, i.e. as either sigma-t or sigma- . This was later modified when it was found that, due to the nonlinearity of the equation of state for seawater, maximum values could exist well above the ocean bottom - ostensibly signifying a hydrostatic instability. The problem was rectified by the use of potential densities calculated relative to different pressures as was required by the situation, i.e. sigma-1 for densities relative to 1000 decibars (db), sigma-2 for 2000 db, etc., a procedure that is still followed today.
Industry:Earth science
An instrument developed at the APL to measure velocity profiles in the ocean. This dropsonde references an electromagnetically inferred velocity profile to one measured near the sea floor.
Industry:Earth science
