GRY 135 - Investigations 8A

19. On the Figure 8A-5 map, the lowest height reported at a station was ______ m.

5410

18. Solid lines on the 500-mb map join locations where the 500-mb pressure level is at the same altitude. These lines, called height contours, are drawn here at intervals of 60 m. The coded height values on the map are in tens of meters, labeled in whole meters. The highest reported 500-mb height at any individual station on the Figure 8A-5 map was ______ m.

5840

24. Therefore, the air below the 500-mb region of lowest heights in Figure 8A-5 must be ______ than the air below the surrounding higher 500-mb surfaces.

Colder

14. The shorter thin blue arrow represents the ______ force, which is acting at a right angle and to the right of the direction of motion.

Coriollis

4. With your cards in the same position as Figure 8A-2iii, place the pencil point at the X and slowly pull the lower left tab of the Card B toward you while slowly moving your pencil away from you, drawing a line along the slit of Card B. Card B is rotating counterclockwise. The line you drew is ______.

Curved

6. When viewed relative to rotating Card B, the path was ______. This apparent deflection of motion from a straight line in a rotating system is called the Coriolis Effect, after Gaspard Gustave de Coriolis (1792-1843), who first explained it mathematically. Because Earth is a rotating system, objects moving across its surface exhibit curved paths, except at the equator. This includes air parcels moving horizontally.

Curved

8. Now imagine yourself far above the South Pole and looking down on the Earth below. Again, think of loose Card B as Earth's surface and X representing the South Pole. From this perspective, Earth appears to rotate clockwise. Rotate Card B clockwise by pulling on the lower-right tab as you draw a line along the slit edge. You observe that as the pencil point moves along the slit and away from the X, it draws a path on the rotating card that ______.

Curves to left

7. Now imagine yourself above the North Pole, looking down on Earth below. Think of loose Card B as Earth's surface and that X represents the North Pole. From this perspective, Earth appears to rotate counterclockwise. If the pencil point moves along the slit and away from the X, it draws a path on the rotating surface that ______.

Curves to right

25. The upper air station model also gives the air temperature at 500 mb. The station data show that as latitude increases (i.e. moving poleward), the decline of 500-mb temperatures is accompanied by a(n) ______ in the altitude of the 500-mb surface.

Decrease

26. Suppose at 00Z 4 December 2017 you board an airplane and fly non-stop directly from Miami, the southern-most station in Florida, to Great Falls, the westernmost station in Montana. En route, the plane cruises along the 500-mb surface. Flying from Miami to Great Falls, the aircraft's actual cruising altitude ______.

Decrease

27. At the same time, the air temperature outside the aircraft ______.

Falls

21. Contour lines on constant-pressure upper-air maps separate regions with higher altitudes from those areas with lower altitudes. In Figure 8A-5, the area to the south of the 5760-m contour across the southern U.S. is where 500-mb altitudes are among the ______. Conversely, the area north of the 5460-m contour line from eastern Washington State to northern Maine is a region where 500-mb altitudes are the lowest.

Highest

17. The frictional force added to the pressure gradient force and the Coriolis Effect causes air to spiral ______ in Lows and outward in Highs.

Inward

11. On the Figure 8A-3 weather map segment, consider an air parcel at rest at Point A. An initial horizontal pressure gradient force ______ acting on the parcel.

Is

10. The Coriolis Effect causes objects in the Southern Hemisphere to appear to curve to the ______ as they move freely across Earth's surface.

Left

1. Figure 8A-1 represents a portion of a surface weather map with three straight, parallel isobars. Pressure is in mb, and isobars are uniformly spaced and drawn with a 4-mb interval. ______ pressure is located across the top of the diagram.

Low

16. Point D shows the effect of friction on moving air. The force of friction, represented by the small green arrow, always acts opposite the direction of motion and slows the moving object, which decreases the Coriolis Effect. As shown by the thick arrow at Point D, the direction of airflow changes and air flows obliquely across isobars toward ______ pressure.

Lower

20. The 500-mb map and other constant-pressure upper-air maps are topographic maps that give shape to imaginary surfaces where air pressure is the same everywhere, revealing "hills" and "valleys" of the constant-pressure surface. The contour pattern of the Figure 8A-5 map indicates the 500-mb surface is at a ______ altitude in southern Canada than in the southern U.S.

Lower

2. The diagram shows a pattern of air pressure changing over distance. Assuming the atmosphere is initially calm, the only force acting horizontally on a parcel of air at Point A is a pressure gradient force. On Figure 8A-1, draw an arrow about a centimeter in length starting at Point A and aimed directly toward the top of the diagram to depict the direction the pressure gradient force acts. The arrow shows the pressure gradient force acting directly toward the ______ pressure. This force is directed perpendicular to the isobar lines. The horizontal pressure gradient creates a force that moves an air parcel at A in the direction the force is acting.

Lowest

28. A relationship exists between the orientation of height contours and wind direction on 500-mb maps, especially at higher wind speeds. As seen in Figure 8A-5 across Utah to New Jersey, wind directions are generally ______ to nearby height contour lines. This is because the frictional forces acting on moving air at and near Earth's surface diminish rapidly with height and are essentially absent in determining middle and upper atmosphere motions.

Parellel

15. From Point C and onward, the air parcel will flow ______ to the isobars. This flow is known as the geostrophic wind.

Parrellel

13. The moving air parcel follows the dashed curved path shown on the map. The thick black arrow at Point B shows the parcel's direction of motion at that location. At Point B, the longer thin red arrow represents the ______ force.

Pressure Gradient

23. There is evidence of a broad ______ across the region from the Great Lakes to the Gulf of Mexico.

Ridge

12. Once horizontal motion has begun at this Northern Hemisphere location, the air parcel's path is deflected to the ______ of its direction of motion.

Right

9. The effect of Earth's rotation on the path of objects moving across its surface is greatest at the poles and diminishes to zero at the equator. The Coriolis Effect causes objects freely moving horizontally over Earth's surface in the Northern Hemisphere to appear to curve to the ______.

Right

3. Orient the cards as shown in the Figure 8A-2iii. Place your pencil point at X. With the cards motionless, carefully draw a line on Card B along the slit and directly away from you. The line you drew represents a path that is ______.

Straight

5. You drew a line on a path both straight and curved at the same time! This is possible because motion is measured relative to a frame of reference. In this demonstration, there are two different frames of reference, one fixed and the other rotating. When the pencil-point motion was observed relative to Card A, its path was ______.

Straight

22. The wave pattern among the contour lines on Figure 8A-5 consists of topographic ridges and troughs, that is, elongated crests and depressions, respectively. A ______ appears over the region from western Canada to southern California and Arizona.

Trough