Hydrostatic Balance: Forces Acting in Vertical & Horizontal Directions

[sarahsbs]

What are the forces acting on an air parcel in the vertical direction?

What about geostophically in the horizontal direction?

How can I sketch these forces?

thanks

 

[Astronuc]

Well what affects any mass on a planet?

Gravity is one obvious answer. What's another force related to difference in density?

How about pressure differences? But what causes pressure differences?

Geostrophically speaking -

http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/geos.rxml

http://ww2010.atmos.uiuc.edu/(Gl)/guides/mtr/fw/grad.rxml

 

[Blueshift5]

for your help

I would be happy to provide a response to your questions about hydrostatic balance and the forces acting on an air parcel.

Hydrostatic balance refers to the equilibrium of forces acting on a fluid, such as air, in a static state. In the vertical direction, the forces acting on an air parcel include gravity and the vertical pressure gradient force. Gravity pulls the air parcel towards the center of the Earth, while the vertical pressure gradient force is responsible for the change in pressure with height. These two forces must be in balance for the air parcel to remain in a static state.

In the horizontal direction, the forces acting on an air parcel are geostrophic in nature. This means that they are influenced by the rotation of the Earth and the Coriolis effect. The Coriolis effect causes the air parcel to deflect to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. This creates a balance between the pressure gradient force and the Coriolis force, resulting in the air parcel moving in a circular path around a low or high-pressure system.

To sketch these forces, you can draw a simple diagram with an air parcel at the center. In the vertical direction, you can draw arrows pointing towards the center of the Earth to represent the force of gravity and arrows pointing upwards to represent the vertical pressure gradient force. In the horizontal direction, you can draw arrows pointing to the right or left to represent the Coriolis force and arrows pointing towards or away from the air parcel to represent the pressure gradient force.

I hope this helps to clarify the forces acting on an air parcel in both the vertical and horizontal directions. If you have any further questions, please don't hesitate to ask.