Posted a couple of days ago on this subject.
The wind blows anti-clockwise round a depression (N Hemisphere). In a stereotypical depression isobars form fairly regular circles round the centre of the depression with kinks at the warm and cold fronts with the isobars in the warm sector generally straight.
Generally the most prevalent forces are the pressure gradient and the Coriolis Effect. I understand the kinks at the fronts are due to thermal disturbances along the fronts (Warm & Cold air mixing) but fail to understand why the isobars in the warm sector are straight. The warm sector seems to be oblivious to the forces acting on the rest of the depression!
I am sure someone can help me in this matter.
Thank you
Mike
maybe think along the lines that the warm fronts are more energy and are more prone to move in the direction that the force of the energy is moving. where as the cloder fronts have less energy and can be easierly influenced by the surrounding invironment. ie. sun, landscape, warm front.
Sorry Spenser this has not helped.
Mike
In case I did not make the question clear.
Why are the isobars straight in the warm sector of a depression?
Thank you
Mike
I think this is because the undercutting of the less dense warm sector air by the relatively more dense cold sector air, induces a small vertical component to the warm sector air mass. This modifies the surface isobar pattern, and, I believe is also accelerates the velocity of the cold front, cf that of the warm front.
Hi Mike,
The isobars in the warm sector of a depression are typically straight because the forces acting in that region are relatively balanced. While the pressure gradient force and the Coriolis Effect are the dominant forces in shaping the overall circulation of a depression, there are other forces at play as well.
In the warm sector, the air mass is relatively warm and moist, and it is characterized by more uniform conditions compared to the colder and drier air masses associated with the fronts. This results in less contrast in temperature and moisture, consequently reducing the potential for significant thermal disturbances or mixing along the warm front.
As a result, the pressure gradient force (which causes air to move from areas of high pressure to areas of low pressure) in the warm sector is relatively weak, as the pressure is more evenly distributed. Additionally, the Coriolis Effect (which deflects moving objects to the right in the Northern Hemisphere) also has a weaker influence in this region due to the more balanced circulation.
Therefore, the combination of these factors leads to the isobars in the warm sector appearing straight rather than forming the characteristic circular pattern seen around the center of the depression. This is because the forces acting on the air in the warm sector are not as pronounced compared to the forces acting on the air along the fronts.
I hope this explanation helps clarify why the isobars in the warm sector of a depression are generally straight. If you have any further questions, feel free to ask!