IX. AIR PRESSURE AND WINDS

Review Questions

1. a) What is the wind? b) Describe and explain the forces that influence wind direction and wind speed. 2. a) What is a pressure gradient? On a weather map, how do you know where the strongest winds are found? 3. a) Weather maps are used to look at spatial variations of pressure. What is the standard isobar interval that is plotted? b) On the current surface weather map of the US, where are the strongest winds? What is the pattern of the isobars? 4. a) The earth's rotation causes an apparent deflection of the air. What is the name of this? b) Where is this strongest? Where is it weakest? c) What is the influence of windspeed? d)What components of wind (direction and speed) does this influence? 5. Consult current weather maps to help answer these questions. a)What is the pattern of flow around a high pressure in the northern and southern hemispheres? b) How is this different to a low pressure system? Why? c) How do wind directions differ at the surface and aloft? 6. a) What is the geostrophic wind? b) Where in the atmosphere will the geostrophic wind occur? c)What shape do the isobars have when the wind is geostrophic? d) On what level weather map would you expect to be able to see the geostrophic wind? 7. a What is the influence of friction on surface winds? b) Compare and contrast a surface and an aloft cyclonic system. c) Where will friction be more significant: over smooth or rough terrain? WIND PATTERNS 1. a) What is a convection cell? b) What produces it? 2 a) How does differential heating result in the generation of winds? Explain the heating patterns and winds that result in: land-sea breezes, monsoons and the global circulation 3. a) What is a chinook? b) What causes it? 4. a)What is a katabatic wind? b) Where does it occur? 5. a) Draw a diagram to show the location of the major pressure systems and winds at the global scale (4 pressure systems; 3 winds in each hemisphere). How are each of the pressure and wind systems formed? b) Why do we have subtropical highs, equatorial lows, subpolar lows and polar highs? c)Why are there bands of westerly winds in the mid-latitudes in both hemispheres when coriolis works in opposite directions? d) Why do these systems not run in perfect symmetrical bands, but bend north and south? 6. a) What is the ITCZ? b) Where does it occur? c) Why does its location vary? d) How would you recognize it on satellite imagery? 7. a) What is a jet stream? b) At what elevation in the atmosphere do jet streams occur? c) On what type of weather map would you look to find evidence of their occurrence? d) Where do the jet streams in each hemisphere occur? e) On the current weather map of the U.S. where is the jet stream located? 8. a) What are Rossby waves? b) How do they affect weather? c) On today's northern hemisphere 500 mb map, how many Rossby waves are evident? Where are they? 9. Explain why: a) At the equator there is a low pressure at the surface but a high pressure aloft (above the surface) b) Deserts are located where they are. c) Tropical rainforests occur at the equator. d) The jet stream moves north and south over the course of a year e) California is hot and dry in the summer and wet in the winter 10. a) Draw a diagram to show the general directions ocean currents flow in the northern and southern hemisphere ocean basins? b)What factors control this? 11. a) What is El-Nino? b) What happens to the ocean circulation during El Nino events? c) What is the effect on global weather patterns