Notes For ERTH 360 Section 1 October 16th, 2018 Maritza Calderon Rachel Urbina Assignments Writing Assignment 1: (Distribution date Tuesday 10/9/2018; Due date Thursday 10/25/18) Do not put in 6-day cycle regarding advection fog since it has not been discussed through lecture Housekeeping and Announcements Office hours 10/10/18 cancelled; Office hours 10/17/2018 ok Halloween Party Readings Gilliam: All Keen, Keen: Chapter 7, Hurricanes; Chapter 8, Local Winds; Chapter 9, How Hot or How Cold; Weather Maps, pp. 231-234 Williams: Chapter 4 (all) (Storms and Fronts); Chapter 5 (all) (Clouds and Precipitation) and Chapter 6 (Floods and Droughts) Hurricane Michael In recent news, Hurricane Michael made landfall recently in Florida as displayed on the Eyewall video during class discussion. The video displayed strong winds and precipitation coherent with a category 4 hurricane. As part of the video, there were houses that were stripped but some that stood due to enforced foundation renovations that helped to increase the survival of their homes, although the monetary cost was much greater. The Eyewall is experienced as a wide opening, similar to the size of a football field with clouds encircling around the eyewall. The video was part of the discussion of hurricane behavior as well as the level of force that was displayed on footage to further illustrate the distinct behavior of hurricanes and present weather discussion. Polar Jet Stream In discussing the 500 mb chart, there are troughs and ridges. The way to visualize the troughs and ridges are to imagine if there is a jump rope tied on to a door knob and if the person were to begin to move the jump rope, the behavior of the wave is fairly similar to the the jet stream
where they move from west to east, with a forward speed of about 50 mph and they look similar to a jump rope when visualized from the side. New Front We have so far learned about three types of fronts; stationary, warm, and cold fronts. In today s class we are presented with another type of front called an occluded front. The term occluded refers to close up. We define occluded front as cold and warm fronts merging together. It is when the cold front catches up to the warm front. On a surface data plot, the occluded front can be identified by a purple line with alternating triangles and semicircles pointing away from the original cold air mass. As the cold fronts and warm fronts merge together creating this occluded front, there is cold air on both sides of the front and will cause the front to eventually die off. Wave Cyclones Along the polar front warm air masses move in different directions with respects to one another in which divergence occurs in a low pressure area that creates a counterclockwise motion in the cold and warm air masses, this then creates a wave cyclone. A wave cyclone can be defined as a frontal cyclone in which air moving counterclockwise and inward induces a wave like configuration in the frontal pattern which then evolves as depicted. During each cycle the waves get larger and intensify. Divergence and Convergence We can define convergence as horizontal air streams mutually coming together and divergence is horizontal air streams mutually splitting apart. Another way to visualize the concept of convergence and divergence is comparing it to the directions of impacted traffic; think about the intensity of traffic at 8am crossing over the bridge to come into the city for people to go to work; this is the direction of convergence; whereas at 5 pm the impact of traffic when everyone is getting off of work and trying to leave the city to go back home, this direction is divergence. Vegetation in Mediterranean Climate We discussed types of plants that can adapt to different types of climates with little or no precipitation over a period of time. One of the terms discussed is sclerophyllous which is the most common type of adaptation to long term dryness made by vegetation in the mediterranean climate zone. It is described as thickened, spongy, waxy leaves to retain water and to restrict water loss. An example of this type of adaptation are oak tree leaves.