METR 1014 1st EditionExam # 3 Study GuideThe following questions/statements are meant to help you focus on the most important concepts thatwe’ve covered so far in class (and in the textbook). They do not represent all possible questions thatcould be asked on the exam.Exam 3 covers Week 9, 11, 12, and 13 slides on D2L (chapters 7, 8, and 10 in the textbook)Describe the formation of the following types of thermal circulations:- Sea breezeSea Breeze Circulation: Morning • Consider the land/sea interface in the morning• Assume that the ocean and land surfaces have the same temperature• Also assume that synoptic-scale phenomena are absent• As solar heating increases during the morning, which surface heats quicker and why? Sea Breeze Circulation: Afternoon• By afternoon (3 PM), land is much warmer than the ocean surface• The air over the land will be warmer - will have expanded in response to surface heating• So, at low levels, have cold column of air over the ocean, warm column of air over the land• This differential heating generates the pressure distribution below- Land breezeo Forms at night as the land cools radioactively more rapidly than the ocean surfaceo Radiative cooling produces the pressure distribution showno Resultant flow pattern o The land breeze tends to be weaker than the sea breeze since the land-ocean temperature difference at night tends to be smaller than during the day.- Mountain breezeo At night the sides of the mountain cool down and cool air is pulled down by gravity. o In the morning, the coldest air is, therefore, often found within the valley. - Valley breezeo During the day the air close to the mountainsides becomes warmer than the surrounding air. o This warm air rises up the mountains and is replaced by air from within the valley. o So during the day valley air moves up the mountainsides.o Max at afternoon, cloudiness and T-storms likely. Describe a monsoon circulation during summer and winter.- Monsoon is used to describe seasonal reversals of wind direction, caused by temperature differences between the land and sea. o Winter: Winds blow off the continents (dry)o Summer: Winds blow from the sea towards the land (moist)- The Monsoon climate in Southeast Asia and India is most well known and most potent. o This circulation is known to bring about long drought periods from September to March. It is hard to grow crops during this period due to the lack of water. o The summer monsoon is known to do the opposite, bringing huge amounts of moisture from the Indian Ocean causing massive flooding in many areas. What is a katabatic wind, and how does it form?• Technically refers to any downslope wind (mountain breeze but stronger)• In more recent times, however, the term katabatic wind usually refers to a cold downslope wind• These winds are observed at every latitude of the globe; wherever cooled air meets a significant slopeMistral Wind – katabatic wind of southeastern France Blows as often as 100 days of the year Described as a "brutal, exhausting wind that can blow the ears off a donkey"• Typically forming in winter conditions, a katabatic wind can develop when a pool of cold, high elevation air begins to descend from the highlands due to the high density of the cold air – gravity carries the cold air over the rim like a waterfall • Katabatic winds may also be synoptically triggered or activated by large scale weather featuressuch as a high pressure system over the high elevations. • One of the strongest katabatic winds on this planet blows in the Antarctic. • Here the lowest layers of the air, sitting on some of the high plateaus, come into contact with the cold dense ice sheet. • These Antarctic winds have been measured at over 200 miles an hour and are some of the strongest winds measured on our planet at ground level, outside those in some tornadoes.What is a Chinook wind, and how does it form?• “Snow eater”• The winds are caused by moist weather patterns, originating off the Pacific coast, cooling as they climb the western slopes, and then rapidly warming as they drop down the eastern side of the mountains. • Warm Dry air moving down the east slopes of the Rockies (Chinook) or Alps (Foehn).• At the eastern foothills of the Rocky Mountains, where the mountains meet the plains, strong winds often sweep down from the eastern slope of the Rockies. • With gusts of 160 kilometers per hour or more, these downslope winds can turn violent, ripping roofs from buildings, snapping power lines, shattering windows, and sandblasting paintfrom cars.What are Santa Ana winds?• Hot, dry winds that often sweep through the L.A. Basin in the fall and winter.• Develop when the desert is cold, and are thus most common during the cool season stretchingfrom October through March. • High pressure builds over the Great Basin (e.g., Nevada) and the cold air there begins to sink. • The fast, hot winds cause vegetation to dry out, increasing the danger of wildfire. Once the fires start, the winds fan the flames and hasten their spread.Know the general circulation pattern (and the names of the surface winds)- On Earth, the circulation in the northern and southern hemispheres is broken into 3 bands in each hemisphere.- Hadley Cell o 0-30 N (S)o Air rises at the equator, travels north and subsides between 25-30 N (S) (Horse Latitudes)o From the center of the Horse Latitudes the surface flow splitso Trade Winds: equator-ward but deflected to the right due to Coriolis o Westerlies: Go towards the poles- Where the trade winds (N and S) meet is called the Doldrums. Light winds and humid conditions.- Ferrell Cell o 30-60 N (S)o More complicated than the Hadley cell.o Net surface flow is toward the poles o Coriolis bends them to the west….called Westerlies!o More sporadic and less reliable than the trade windso Migration of cyclones and anti-cyclones disrupts the general westerly flow.- Polar Cell o 60-90 N (S)o Subsidence at the poles produces a surface flow that moves equatorward and is deflected by Coriolis into the Polar Easterlies.o As cold air moves equatorward it meets with the warmer westerly flow and clashes forming the Polar Front.- Trade Winds o Warm air rises near the equator and moves northward through the upper atmosphere.This airflow sinks back to the earth’s surface at 30°N/S latitude and flows back towards the equator. o Trade winds are felt 83-95% of the time in the summer and 42-60% of the