ENVS 101 1st Edition Lecture 21 Outline of Last Lecture I. Earth’s Climatic SystemII. Evidence of Climatic ChangeOutline of Current LectureIII. Regional wind and Weather systemsIV. Wind and Weather effects and SystemsCurrent LectureSevere Weather: Tornadoes or funnel clouds, are a spiraling column of air that extends downward from a cumulonimbus cloud. - They typically develop from large thunderstorms that have multiple updrafts (supercell thunderstorms) - They are most active during the span of time that occurs from the month of April through August.- Tornadoes are also generated from wind shear: which are winds moving indifferent directions at different levels of atmos. - The largest variety of tornadoes will span about a mile across at most, but anything within this distance will be destroyed by the path of a tornado. - They are very common when cool, dry air off of the Rocky mountains region meets warm air that comes form the Southeastern region of the United States.Drought- Below-average rainfall for an extended period of time. This often comes with an emphasis on affected water supply or harvests. Semi-arid areas adjacent to desert regions are highly susceptible to drought. The expansion of desert conditions into adjacent areas is called desertification. This is due to both natural causes, such as drought, as well as overgrazing and poor land-use practices.Dust Storms- Once in the air, dust constitutes the wind’s suspended load.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.The weather system of the Earth is full of feedback effects, both positive as well as negative. Prolonged drought leads to: vegetation dying out, which leads to: a dust storm, which leads to: desertification: even more droughtThe Earth’s response to this particular situation is a positive feedback, because the end result of the response led to an increase in the drought that was already present in this hypothetical environment.In a positive feedback situation, a prolonged drought might reach a point (a threshold) where it becomes impossible to recover to its former state. The end result of this is a new, drier “normal” would be established.Monsoons are seasonally reversing windsThe monsoon of the Southwestern United States is similar to a large-scale sea-land breeze. During the summer, hot rising air generates a low-pressure system that draws in moisture form the Gulf of California. In winter, the region cools down, and dry air ends up sinking down and spreading out.El Niño and Southern Oscillation- In a normal situation: Off the coast of Peru, cold upwellingsustains fishing grounds with nutrients. The process is driven by Northward and Westward air and water currents. High pressure will be present around the area near Peru, while lowerpressure will be present near the area surrounding Indonesia. Overall, the high and low pressures will undergo a swap situation in which the ocean currents are weakened as a result. With El Niño: As high and low pressures switch as an effect of southern oscillation, the winds slacken and warm water will slosh back over to Peru, towards the equatorial counter current. The dry parts of Peru will end up receiving heavy rains and fisheries fail. Australia and Indonesia both experience drought, and cyclones will appear within the regions of Hawaii as well as French Polynesia.La Niña: Extreme “normal” condition, the opposite of effects that are brought about by El Niño. In these conditions, Indonesia and Australia actually experience flooding, and Peru willundergo drought conditions. Both of these conditions are episodic, and alternate between over monthly to yearly time