Geography 103:  Weather

Exercise 7.  An 850 mb temperature chart.

 

The map below shows the temperature at the 850 mb level for January 13, 2004.  This was obtained from the web site weather.unisys.com.  Go to this site to find instructions for reading and interpreting this.

 

Please use the data sheet to answer the questions following.

 

Approximately what altitude does this chart correspond to (in meters/km)?

 

What units are the temperatures given in?

 

What is the separation of adjacent contours (in °)?

 

Where is it warmest at this level - at the top (north) or the bottom (south)?

 

Mark the location of Los Angeles.  What is the approximate temperature at 850 mb for Los Angeles?

 

Mark the location of Seattle.  What is the approximate temperature at 850 mb for Seattle?

 

Mark the location of Boston.  What is the approximate temperature at 850 mb for Boston?

 

Look back at your chart of 1000 - 500 mb thicknesses for this date.  How are the temperatures at 850 mb related to these thicknesses?

 

There is a local low temperature in the NE corner of Nevada, what is the approximate minimum temperature here?

 

Does this low correspond to locally large or small thicknesses in the 1000 - 500 mb layer?

 

There is a local high temperature in the western part of Montana.  What is the approximate maximum temperature there?

 

Does this high correspond to locally large or small thicknesses in the 1000 - 500 mb layer?

 

Mark the location of Chicago on your map.  Chicago is at roughly the same latitude as the border between California and Oregon.  What is the temperature of Chicago at 850 mb?

 

What is the temperature at the border between California and Oregon on the west coast at 850 mb?

 

Why is Chicago so much colder?