Exam #2 Study Guide Lectures: 9-15Lecture 9 (October 1)What are two types of weather maps and what are the differences?There are Constant Height Maps and Constant Pressure Maps. Constant height maps have the same elevation everywhere and the pressure varies. An example of a constant heigh map are sur-face maps. Constant pressure maps are upper-air maps and have the same pressure everywhere.**What are high and low heights indicative of relating to pressure level?** How do troughs and ridges relate to this?High heights are indicative of warm air below that pressure level because warm air is less dense than cold air. Low heights are indicative of cold air because as you heat air, it expands. High heights on a constant pressure surface are analogous to high pressures on a constant height sur-face. Low heights on a constant pressure surface are analogous to low pressures on a constant height surface. Troughs have low heights and ridges have hig heights. Remember DO NOT just look at the shape of the contour lines.What does Newton’s Second Law say?Newton’s second law says that a net force is required to accelerate any object, including air. This is the pressure gradient force. What is Coriolis Force?Coriolis force is apparent force due to rotation of earth. Friction is near-surface flow only and gravity is vertical motions only. What is the law of pressure?ATMS 100 1st EditionPresure is force divided by area. It is related to the weight of the atmosphere above you. The greater mass of air above a high pressure system than above a low.What is Pressure Gradient?Pressure Gradient means air molecules want to flow from where there is greater pressure to where there is less pressure. An extreme case of this is a vacuum. Increasing pressure gradient yields greater acceleration and faster flow.What is Pressure Gradient Force?Pressure Gradient Force is change in pressure over distance. If isobars are tightly packed, there isa strong pressure gradient (big change over a small distance). If isobars are widely spaced, there is a weak pressure gradient (small change over big distance). The Pressure Gradient Force is di-rected from higher to lower pressure (heigher to lower heights); It acts pependicular to iso-bars. Pressure Gradient Force causes winds to blow; the stronger Pressure Gradient Force means stronger winds. What is the correlation between the rotation of the earth and the Coriolis Force?While viewing earth from the North Pole, the earth rotates counter-clockwise. The surface rotatesfaster near the equator and slower at the poles. As air from Pole moves southward (outward), it moves slower than the air/ground around it and appears to be deflected westward.**Northward (south winds) moving objects rotate faster than ground beneath them anda appear to be deflected eastward. Southward (north winds) moving objects rotate slow than ground be-neath them and appear to be deflected westward. Eastward (west winds) moving objects de-flected outward from axis of rotation. Westward (east winds) moving objects deflected inward toward axis of rotation.What is the correlation between latitude and the Coriolis Force?Coriolis Force is maximum at Poles and minimum at equator.What is Coriolis Force in the Northern and Southern Hemispheres?Corilois force deflects objects to the right (not necessarily to the east) in the Northern Hemi-sphere. Coriolis force deflects objects to the left (not necessarily to the west) in the Southern Hemisphere. Coriolis force changes the direction, not the speed of motion. Lecture 10 (October 6)Where does PGF act perpendicular to?PGF acts perpendicular towards low heights or low pressures and it’s magnitude is determined by the spacing of height lines.Where does Coriolis force act to?CF always acts to the right of motion in the Northern Hemisphere. The magnitude of CF is pro-portinal to wind speed. Friction is not important at upper levels.What is Geostrophic Wind?Geostrophic wind is wind that is parallel to isobars/height contours.What is the correlation betwen PGF and CF?PGF balances CF. It forces the same magnitude but in opposite directions. Net force on air is zero. Assumes straight isobars. The stronger the PGF, faster the winds. The tighter the countour lines, the faster the winds.How do you determine wind direction?If wind hits you from your back, low heights/pressures are on your left (in the upper level flow and Northern Hemisphere only). **How do you analyze upper-air maps?**The PGF is always perpendicular to height lines and low heights/pressure. Wind is always low heights/pressure on your left. CF is always perpendicular to the right of the wind. Geostrophic winds blow parallel to height lines such that if the wind hits you in the back, low heights are on your left. CF acts perpendicular (or opposite direction of PGF) to the right of the wind direction.What is necessary for curved flow to happen?For curved flow to happen, PGF and Coriolis force cannot balance because balanced forces means no acceleration. One force must be greater than the other because there must be a net in-ward force to change direct. What is the correlation between PGF and CF around lows?PGF is directed inward to the center of the low and CF is directed outward to right of the winds. For curved flow, net force must be directed inward toward center of the low. The PGF must be greater than the CF around lows.What is the correlation between PGF and CF around Highs?PGF is directed outward from the center of the high. CF is directed inward to the right of winds. For curved flow, net force must be directed inward toward center high. Coriolis Force must be greater than PGF around highs. What are the above things called?**Gradient wind balance**; although PGF and CF are not balanced. Force imbalances are neces-sary or flow would not go in a circle. Net force inward to center of circle is necessary. PGF is de-termined by height gradient, CF is determined by wind speed. **Wind speed will be faster around highs and slower around lows.**What is zonal and meridional flows?ZOnal flow is westerly flow. Meridional flow is northerly/southerly flow. Warmer air (high heights) is typically found in the tropics and colder air (low heights) typically found near the poles.What are cyclones?Cyclones are low pressure systems. In the Northern Hemisphere, they flow counter-clockwise. Inthe Southern Hemisphere, they flow clockwise.What are anti-cyclones?Anti-cyclones are high pressure systems. In the northen