WW2010
University of Illinois

WW2010
 
  welcome
 
> online guides
 
  archives
 
  educational cd-rom
 
  current weather
 
  about ww2010
 
  index

Online Guides
 
  introduction
 
  meteorology
 
  remote sensing
 
> reading maps
 
  projects, activities

Reading Maps
 
  introduction
 
  utc conversions
 
  temp conversions
 
> surface obs
 
  surface maps
 
  upper air obs

Surface Obs
 
  overview
 
  temperature
 
  weather
 
  dew points
 
  cloud cover
 
  pressure
 
  winds
 
> contours

Contours
 
  introduction
 
  isobars
 
  wind & isobars
 
  isotherms
 
  isodrosotherms
 
> more contouring

User Interface
 
  graphics
> text

NOTE: We've guessed that you're not using a client that supports colored tables and have tried to compensate. Low graphics mode looks much better on clients that do... we recommend switching to Netscape 3.0 or Microsoft Internet Explorer.
.
Contouring
surface maps

Sometimes the reported values (black numbers) are not always located between the correct contours. For example, in the dew point temperature map below, a station in Minnesota (circled in blue) reported a dew point temperature of 52 degrees, but it is located between the 60 and 65 degree contours.

Why is this so? Because contours are plotted to provide a "best-fit" for all reports, which include a very large number of stations. To give you an idea, I've increased the number of reporting stations in the image below.

This is the exact same dew point map, but with many more station reports (black numbers). And this still doesn't include all of them!

In order for every station to be within the correct contours, lines would be zigging and zagging everywhere, making the map unreadable. Fortunately, contour lines are smoothed to make the map readable.

Therefore, it is important to remember that although the contours may not be 100% accurate for every single reporting station, contouring provides READABLE information, as accurately as possible, for a HUGE number of reporting stations.



isodrosotherms
Terms for using data resources. CD-ROM available.
Credits and Acknowledgments for WW2010.
Department of Atmospheric Sciences (DAS) at
the University of Illinois at Urbana-Champaign.

Temperature Maps