Weasther/Climate: Chapter 6

  1. What is air pressure?
    The weight of the pressure that the air exerts on the surface of the earth.
  2. What is atmospheric pressure moswt closely related to?
    Atmospheric pressure is most closely related to the temperature and the density of the air.
  3. How is atmospheric pressure affected by density?
    Atmosperic pressure is affected by density because the higher the altitude, the less gravity there is, meaning the less molecules and less density, hence lower air pressure.
  4. How is atmospheric pressure affected by temperature?
    Atmospheric pressure is affected by temperature because when air is close the Earth, it warms which causes the molecuses to scatter and thus makes it less dense, resulting in a low air pressure. Cold air is associated with high atmosperic pressure because cold air sinks and is thus very dense.
  5. How is air pressure measured and in what unit?
    Air pressure is measured by an instrument called a barometer and is measured in millibars (mb).
  6. What is a high pressure system?
    A high pressure system is a circulating body of air that exerts high pressure on the Earth's surface because air descends toward the surface in the core of the system.
  7. What is a low pressure system?
    A low pressure system is a circulating body of air that exerts low pressure on the surface of the Earth because the air is rising from the center of the system.
  8. What are low pressure systems known as, how do they spin, and what type of weather is it associated with?
    Low pressure systems are aso known as cyclones, they spin counterclockwise (in the North), and they are usually associated with cloudy or stormy weather (because the air rises from the core and as it rises it cools; cold air holds less moiswture).
  9. What is a high pressure system also known as, how does it spin, and what type of weather is it usually associated with?
    A high pressure system is also known as anticyclone, it spins clockwise (in the north), and usually associated with fair weather (because in a high pressure system air descends and as it descends it warms up; warm air can hold more moisture).
  10. Info Card: The void filled from rising air in a low pressure system is replaced by the descending air in a high pressure system. This exchange of air is what we come to feel as wind.
  11. What causes wind?
    Wind is caused by unequal heating of land surfaces.
  12. What is advection?
    Advection refers to the horizontal movement of air.
  13. What is convection?
    Convection is the vertical mixing of air due to differences in temperatures.
  14. Info Card: Once air is in motion due to the process of convection and advection, pressure gradient force, Coriolis force, and frictional force incluence the movement of air.
  15. What is pressure gradient force?
    Pressure gradient force is what drives the movement of air between two areas of different pressure.
  16. Info Card: Pressure gradient force works like slope. The greater the elevation between two ares being measured, the steeper the pressure gradient. The greater the pressure gradient, the faster air flows to balance it.
  17. What does widely spaced isobars mean? What does closely spaces isobars mean?
    Widely spaced isobars means very limited pressure change occurs. Closely spaced isobars means that a rapid change in pressure occurs over a small space.
  18. What is Coriolis force?
    Coriolis force is the force created by the Earth's rotation that causes the winds to be deflected to the right in the northern hemisphere and to the left in the southern hemisphere.
  19. Where is air influenced by the Coriolis Force?
    In the upper Trooshpere
  20. Info Card: Once air rises into the upper Troposhere, it flows more freely without obstruction and is hence faster.
  21. What are Frictional forces?
    Frictional forces occur at ground level and operate in direct opposition to the wind.
  22. What creates Frictional forces?
    Frictional Forces are created by structures on the Earth's surface.
  23. Info Card: Frictional forces balance the presure gradient fore Coriolis force so that winds flow in between.
  24. Info Card: Air flows from the equator which is a low pressure system and flows to the poles which is a high pressure system to create a balance.
  25. What are monsoons?
    The monsson is the seasonal change in wind direction that occurs in subtropical locations due to the moving of the ITCZ.
  26. Where are monsoons sometimes seen and where are they most commonly seen?
    Monsoons are sometimes seen through subtropical regions an they are most commonly seen in S.E. Asia.
  27. What are Sea Breezes?
    Sea breezes are when wind over high pressure water moves to an are of low pressure land.
  28. Where are Land-Sea Breezess most commonly found?
    Land-sea breezes are most commonly found along the coast.
  29. Info Card: The sea breeze reverses at night because land cools more rapidly than water and hence becomes an area of high pressure and the water becomes an area of low pressure. When this occurs, the air changes direction and moves fron land to sea in what is known as land breeze.
  30. What are Land Breezes?
    Land breezes are when the wind from an area of high pressure land flows to an area of low pressure over the water.
  31. What are topographic winds?
    Winds that form due to variations in topography (which is changes in the Earth's surface)
  32. Why do topographic winds generally form?
    Topographic winds generally form because large temperature differences can occur with elevation in hills and mountains.
  33. What are two types of topographic winds?
    Valley breeze and mountain breeze
  34. What is a valley breeze?
    Valley breeze is when heat from the sun strikes the top of a mountain, causing warm air which then rises & creates an area of low pressure in which air from the valley flows to fill the void. (At night this switches and is called a mountain breeze)
  35. What is a mountain breeze?
    A mountain breeze is when the heat from a valley breeze is lost at the top of the mountain creating cold air which then sinks into the valley.
  36. What are katabotic winds?
    Katabotic winds which generally form in cold places, is when extremely cold air forms over high altitude places covered by ice and then flows downhill through the valley.
  37. What are chinook winds?
    Chinook winds are a downward flow of air that occurs when a zone of high air pressure exist on one side of a mountain and low pressure exist on the other side.
  38. What is the Windward side?
    The windwrd side is the side of the mountain that faces the oncoming winds.
  39. What is the Leeward side?
    The leeward side is the side of the mountain that faces away from the oncoming winds.
  40. What are gyres?
    Gyres are distinct circulatory systems of water that form due to continents blocking the movement of water.
  41. What is Thermohaline Circulation?
    Thermohaline Circulation is the oceanic circulation system that is driven by differences in salinity. (Water closer to the surface is warmer and less salty thn deeper water)
  42. What happens to warm Carribean water as it travels up north due to the Thermohaline circulation?
    As the water travels up north, it becones saltier and colder.
  43. What is a downwelling current?
    A downwelling current is water that sinks to great depths in the ocean because it becomes colder and saltier.
Card Set
Weasther/Climate: Chapter 6
Flashards for Exam #2