The density of water changes during different seasons...if during summer I measure the depth of sea with SONAR device and at an approx it's 20m..but than when I come back to measure the depth in winter I notice a change in density of water...and a change in density can cause a change in speed of sound..so now when I measure in different circumstances i.e in Winter due to the speed I get a different value of depth..now how can the depth of the sea vary?
Answers
Answer:
Density of seawater and pressure
The density of a material is given in units of mass per unit volume and expressed in kilograms per cubic metre in the SI system of units. In oceanography the density of seawater has been expressed historically in grams per cubic centimetre. The density of seawater is a function of temperature, salinity, and pressure. Because oceanographers require density measurements to be accurate to the fifth decimal place, manipulation of the data requires writing many numbers to record each measurement. Also, the pressure effect can be neglected in many instances by using potential temperature. These two factors led oceanographers to adopt a density unit called sigma-t (σt). This value is obtained by subtracting 1.0 from the density and multiplying the remainder by 1,000. The σt has no units and is an abbreviated density of seawater controlled by salinity and temperature only. The σt of seawater increases with increasing salinity and decreasing temperature.
The relationship between pressure and density is demonstrated by observing the effect of pressure on the density of seawater at 35 psu and 0 °C. Because a one-metre (three-foot) column of seawater produces a pressure of about one decibar (0.1 atmosphere), the pressure in decibars is approximately equal to the depth in metres. (One decibar is one-tenth of a bar, which in turn is equal to 105 newtons per square metre.)
Values associated with the change in seawater density with depth are listed in the table
Explanation:
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