Notes

Slide Show

Outline

1	Chapter 3: Weather Map
2	Weather Maps Many variables are needed to described weather conditions. Local weathers are affected by weather pattern. We need to see all the numbers describing weathers at many locations. We need weather maps. “A picture is worth a thousand words”.
3	The Station Model
4	Weather Map on 7/7/2005
5	Isobar It is useful to examine horizontal pressure differences across space. Pressure maps depict isobars, lines of equal pressure. Through analysis of isobaric charts, pressure gradients are apparent. Steep (weak) pressure gradients are indicated by closely (widely) spaced isobars.
6	The Station Model: Cloudiness
7	The Station Model: Wind
8	The Station Model: Pressure
9	Pressure Correction for Elevation Pressure decreases with height. Recording actual pressures may be misleading as a result. All recording stations are reduced to sea level pressure equivalents to facilitate horizontal comparisons. Near the surface, the pressure decreases about 100mb by moving 1km higher in elevation.
10	The Station Model: Pressure Tendency
11	The Station Model: Dew Point Temperature
12	The Station Model: Significant Weather
13	Contour Lines on Weather Maps
14	Pressure As a Vertical Coordinate
15	Pressure Surface
16	Height (Pressure) Map at a Constant Pressure (Height)
17	Upper-Level Weather Maps Meteorologists use height maps at constant pressure levels to describe weather conditions in the upper atmosphere. On constant pressure maps, we can infer a strong pressure gradient exists where a strong height gradient exists. Height maximum è high pressure. Height minimum è low pressure.
18	Station Model in Upper-Level Weather Maps
19	Other Upper-Level Weather Maps 850mb: to identify fronts 700mb: intersects many clouds; moisture information is important 500mb: used to determine the location of short waves and long waves associated with the ridges and troughs in the flow pattern. Meteorologists examine “vorticity” (i.e. rotation of air) on this pressure level. 300, 250, and 200mb: near the top of the troposphere or the lower stratosphere; these maps are used to identify the location of jetsreams that steer the movements of mid-latitude storms.
20	Example: A 850mb Weather Map
21	Example: A 300mb Weather Map
22	Example: 500mb Weather Map
23	Vorticity Vorticity is the tendency for elements of the fluid to "spin.“. Vorticity can be related to the amount of “circulation” or "rotation" (or more strictly, the local angular rate of rotation) in a fluid. Definition:
24	Three Sources of Vorticity
25	Vorticity-Related Flow Patterns