Since the formation of Earth, friction has been a constant force upon it. This friction
has slowed the Earth's spin down more and more as time passes. The main
cause of the slowing in Earth's spin is the moon, as its gravity tugs on earth.
This slowing of Earth's spin has been determined to be about 1.4 milliseconds
per solar day per century. This means in the year 1907 days were 1.4
milliseconds shorter. This has added up significantly over the course of time,
scientists have determined days were about 6.5 hours long when Earth was first
created. More info here: Information on the Slowing of Earth's Rotation
Of course, the rotational speed of Earth strongly ties into the Coriolis force. It is
easily seen that a slower rotation of Earth about its axis will result in less
Coriolis force but, by how much and over what time is the question. This will
require quite a bit of math.
The horizontal acceleration of the Coriolis force is calculated with the formula
a=fv
where
v is the horizontal component of the velocity
f= 2(omega)Vsin(theta).
omega= angular velocity of earth
V= velocity of object relative to Earth
theta= latitude in degrees
So, the variable we will be dealing with is the angular velocity of Earth, which
requires another formula.
2pie/ time
The current length of a day is 86164.09 seconds. This means that the current angular
velocity of earth is 7.2921159 X 10 to the -5 radians per second. When
this is equated into the Coriolis formulas, our constants will be 40 degrees
of latitude and 20 km/h of movement[/b], it results in a current Coriolis
parameter of 0.0018749127, which in turn makes a horizontal
acceleration of .037498254.
Now that the Coriolis force can be calculated, one must see how it will change over
time with the slowing of 1.4 milliseconds per solar day per century. I have
made a graph of it below. 1 is the current and every data point after that
is another one hundred million years into the future. Thus, a slow decline in
the Coriolis' horizontal acceleration is taking place.
So, the horizontal acceleration of the Coriolis force is decreasing by roughly 5.99 X
10 to the -5 per one hundred million years.
In weather, this decrease in horizontal acceleration of the Coriolis force will have
major effects. Net vorticity of the atmosphere will decrease as the horizontal
acceleration of the Coriolis force provides less and less kinetic energy to the
atmosphere. Cyclonic movement will become weaker on the whole. Using the
data, the horizontal acceleration on Earth will decrease by about 15.9% off the
current per one hundred million years, [b]which can be seen as 15.9% less
energy being infused into the atmosphere due to the Coriolis effect per one
hundred million years.
Although this decrease in Coriolis force will not have a large affect on weather for
millions of years, it is still interesting to ponder.
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