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6.5: Cyclonic and Anticyclonic flow in real life.

  • Page ID
    44404
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    Finding a "mystery pressure"

    Figure 6.5.1 is a map of surface observations at 1900 UTC on August 30, 2017. Remember that the long poles extending from each circle is pointing in the direction that the wind is coming from. There is a “mystery” pressure system over Eastern Louisiana, indicated by a green “?” Your mission, should you choose to accept it (and you must if you want those precious points!) is to identify the type of pressure system.

    Surface Station Model Map for Southeast United States. Details in Caption
    Figure \(\PageIndex{1}\): Map of Surface data at 1900 UTC on August 30, 2017. Note a "mystery pressure" system is identified as a green question mark in Eastern Louisiana. (CC BY-NC 4.0American Meteorological Society via Unidata). Alternative description of image.  
    1. In general, winds on the Western side of the “mystery” pressure are blowing from the:
      1. North, Northwest, and Northeast.
      2. West, and Southwest
      3. South and Southeast
      4. East, and Northeast

    Print out Figure 6.5.1 (or use a “paint” program) and draw arrows indicating the motions you selected for Question 18. 

    1. In general, winds on the Eastern side of the “mystery” pressure are blowing from the:
      1. North, Northwest, and Northeast.
      2. West, and Southwest.
      3. South and Southeast.
      4. East, and Northeast.

    Draw arrows indicating the motions you selected for Question 19.

    1. Putting these two findings together, the motion around this mystery pressure is generally:
      1. Clockwise
      2. Counter-Clockwise
    2. The direction of the rotation, along with the presence of clouds and stormy weather conditions indicate that this pressure system is indeed a: 
      1. High Pressure System
      2. Low Pressure System. 

    Convergence and Divergence

    The previous situation was a demonstration of Convergence, which occurs when air flows into a center of pressure. Once the air reaches the center, it has nowhere to go but up. 

    1. Convergence must occur in a ______________ pressure system.
      1. Low
      2. High

    On the other hand, Divergence occurs when air is moving away from a center of pressure. In this case, air from above has to sink to fill in the empty space previously occupied by the escaping air. This causes sinking motion in an area of divergence. 

    1. Divergence must occur in a _________________ pressure system.
      1. Low
      2. High

    This page titled 6.5: Cyclonic and Anticyclonic flow in real life. is shared under a CC BY 4.0 license and was authored, remixed, and/or curated by Neel Desai & Alicia Mullens .