WW2010
University of Illinois

WW2010
 
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Reading Maps
 
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> surface maps
 
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Surafce Maps
 
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> analysis pairs

Analysis Pairs
 
  press & temp
 
  dew point
 
  weather
 
  wind
 
> mixing ratio
 
  moist. convergence
 
  temp. advection
 
  dew point advect
 
  3hr dew pt & wind
 
  3hr temp & wind
 
  3hr press & wind
 
  frontogenesis

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.
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Pressure and Mixing Ratio
surface analysis pairs


Example Pressure and Mixing Ratio

This panel depicts sea-level pressure and mixing ratio. This chart is useful for finding high and low pressure systems. Its also useful for showing regions of moist air at the surface.

The solid white contours represent pressure contours (isobars) in millibars. The isobars have a contour interval of four millibars. The wind speed is directly related to the distance between the isobars. The closer the isobars are together, the stronger the pressure gradient, and the stronger the wind.

The dashed green lines represent lines of equal mixing ratio. Mixing ratio has a contour interval of two grams per kilogram. Mixing ratio is another convenient way to express humidity. Mixing ratio is the mass of the water vapor in a parcel to the mass of the remaining dry air. Another way to express that is Mixing ratio = mass of water vapor / mass of dry air. The units are grams per kilogram. Example: If you have a mixing ratio of 5, that means you have 5 grams of water vapor to every kilogram of dry air.

From the map above you can sometimes find warm fronts, cold fronts, and drylines. Fronts are usually located where the mixing ratio changes drastically over a short distance. A dryline is also an area where mixing ratio changes drastically over a short distance. During the day, temperatures are warmer west of the dryline and at night they are warmer on the east. Drylines can usually be found in the Plains during the development of low pressure systems.

This image shows a very strong dryline (coldfront) located over the Midwest. The strong front preceded the tornado outbreak on July 2, 1997 that hit parts of Michigan, Indiana and Ohio.

For more information on how pressure affects the weather go to our pressure module.



wind
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.

moist. convergence