Deflection of Winds, Oceanic Currents & Coriolis Theory

Deflection of Winds & Oceanic Currents

The wind is always named according to its source. Similarly, the banks of rivers are named in respect to the Origin of the river.

Since the earth rotates from West to East, winds which are northerly & westerly are deflected from their paths. The force which deflects these winds from their paths is due to the rotating force of earth called Coriolis Force.

The amount of deflection of winds is directly proportional to sin

                                    i.e., Deflection ∞ sin

In both hemispheres, the amount of deflation of winds increases as one moves from the equator to poles.

The direction of deflation of wind will be Right-hand side with respect to origin in Northern Hemisphere

& Left-hand side with respect to origin in Southern Hemisphere.

CORIOLIS THEORY

Any fluid that travels across the earth follows the law of conservation of angular momentum since Earth is a rotating frame. According to it,

Therefore, as the radius of the earth decreases, the angular velocity has to increase to keep/ conserve its angular momentum.

Similarly, as the radius of Earth increases, the angular velocity has to decrease to conserve its angular momentum. Since we know that earth is Geoid shaped and its radius increases as we move from poles towards the equator, this is the reason for the more Coriolis force at poles than the equator.

When wind moves from the lower latitudes to higher latitudes its velocity increases, consequently the wind combining this with the rotation of the earth from West to East, the wind is deflected to its right. This combined force is called the Coriolis force.

The Appearance of Moon & Tides

Only one side of the moon is visible to the earth. Sidereal Period is the period of revolution of the moon around the earth.

The time taken for a full moon to reappear is not 27.3 days but it has to compensate the distance traveled by the earth in the same period. The earth travels 30o in one full month. The distance of the moon and earth is calculated as under.

The Lunar Calendar is based on this cycle (Hindu & Muslim Calendar). Translating the above data, we obtain for the appearance of the full moon on earth (for tides).

Therefore, for one rotation of the earth, the moon reappears at a particular location by compensation of this 12o12’. The Earth thus has to be compensating this distance as under:

Revolution of Earth and Tilt of Earth

Revolution of the earth around the sun to produce the following effects:

  1. Length of day and night
  2. The altitude of the mid-day sun
  3. Seasons

Greater the tilt, greater the personal contract. Mars has a tilt of 24o which is very similar to; the tilt of earth =23.5o. Hence, the weather pattern of mars is similar to earth.

Note: The above case is for Equinox is where the midday sun is directly overhead the equator.

Equinoxes and Solstices

Equinox is the phenomenon when the mid-day sun is directly above the equator. This happens twice a year. The mid-day sun moves from 0o to 23.5oLatitude due to the tilt of Earth. Seasonal changes are due to this, combined with the fact that earth also revolves around the sun. During Equinox, the length of the day and night are equal.

Solstice, on the other hand, is the phenomenon when the mid-day sun is directly above the Tropic of Cancer in Summer Solstice 23 1/2o N and the Tropic of Capricorn in Winter Solstice 231/2o S. Solstices are named with respect to the Northern hemisphere since only the northern hemisphere was said to be civilized in those days when astronomy & geography were just beginning to develop.