FRONTS AND  FRONTOGENESIS

Front : Sloping boundary which  separates two opposing  air masses having  contrasting  characteristics in terms of temprature, humidity, density, pressure and wired direction 

Frontal Zone /Frontal Surface : Represent zone of discontinuity  is the properties of opposing  contrasting air masses.

FRONTOGENESIS : Process  associated  with the creation of new fronts or the regeneration of decaying fronts  already in existence is called frontogenesis.

FRONTOCYSIS : Process of destruction or decaying of fronts is called FRONTOCYSISNecessary  Condition  for frontogenesis.

Pressure of two opposing  air masses having  contrasting  properties of air temperature , air pressure, density , humidity, and weird direction.

Inspite of  Convergence of two air masses at the equator no front is formed due to uniform temperature  condition of  two air masses.

Four Types Of  Air Circulation:

• Translatory  Circulation : Movement of air is horizontal direction from one place to another place is same direction.

• Translatory  Circulation does  not  favor  the  creation of  fronts.

• Rotatory Circulation : Circulation of air is Cyclic and Anticyclic  pattern.

• Rotatory Air Circulation produces  temperature  variation but front is never created.

Convergent and Divergent Circulation:  

• Convergent Circulation –Meetings of wired at common point from all direction.

• Divergent Circulation- Spread of weird air outward direction.

Deformatory Circulation : Involves  convergue  of two contrasting  air masses and horizontal spread along  line which is called air axis of outflow or axis of diacation.

Other axis is called axis of inflow. This type of air circulation is most favourable  for frontozeniesis.

CREATION OF FRONTS  : Contrasting air masses converge  is deformation circulation they spread horizontally alng the axis of outflow dialaction.

In such  a  situation creation of fronts depend on angle between the axis of outflow  and isotherms. 

Front don’t form  when angle exceeds 45 degree.

As the convergence of air continues –Angel  decreases  and  isotherm tries to become parallel to the axis of overflow  and FRONTOGENESIS gets activated.

Steepness and intensity of fronts depends on temperature gradient.

If two contrasting air masses are parallel to each other and there is no upward displacement  of air -Stationary front is formed.

Stationary front  Climatical  air significant – Not Conductive for cloud formation and preparation 

Fronts are not linear between two converging contrasting air masses.

Fronts are formed only in the areas were two air masses converge. The three principal frontal zones on the earth surface.

• Polar Frontal Zone.
•  Artic  Frontal Zone.
• Inter tropical Frontal Zone.
• Polar Frontal Zone / Atlantic Polar Front.

Polar Front:  are formed is the middle attitudes in both the hemisphere because convergence of polar contenental air masses and  tropical air mass.

More developed in northern part of pacific and Atlantic ocean .

Temperate  cyclone produced along polar front travel from west to east under this influences of west lies and yield widespread precipitation over large area Extending from  the eastern parts of North America to Western Europe.

Polar front is wcakened during summer season because the temperature contrast between two air masses is minimum.

Artic Frontal Zone : Created in artic area due to convergence of continental and maritime polar air masses.

Not very strong and active because of less temperature contrast between two air masses.

Active fronts are formed – Relatively warm polar maritime air masses meets extremely cold and artic air masses due to which temperature contrast are accentuated.

MEDITERRANEAN FRONTAL ZONE : Formed due to convergence of cold continental European air masses and winter air masses of North Africa. Along  Mediterranean caspian sea live.

-Some  of these frontal weather disturbance reach Pakistan and north –west India and account for winter precipitation of North India.

Pacific Polar Frontal Zone : Two Frontal zones develop during winter season over the North Pacific ocean.

Frontal disturbance developed along the frontal zone of north-easr pacific ocean influence the winter time weather condition of western coast of North America 

Pacific Artic Frontal zone : Developed along a time running from the rocky mountain to the great cakes during the winter season.

Intertropical Frontal Zone :Tropical front is formed near the equator due to convergence of North East and South East trade wind. 

It may be pointed out that there is no temperature contrast between these two air masses of similar origin and similar properties

Changing weather associated with Fronts : Precipitation of long duration , Cloud Sequences Ciro-stratus , alto stratus and nimbo  stratus.