Water vapor imagery

[Jared Farrer]

How would one spot out short waves on water vapor imagery? I dont use satellite infrared and water vapor much, but I am starting to. Do any of you have any tips or tricks when it comes to these two channels?

 

[Bill Schintler]

WV imagery interpretation

First, WV imagery uses a wavelength roughly 15 times longer (in the IR) then visible light. This particular wavelength, about 7000 nm, is readily absorbed by the atmosphere. This allows for atmospheric gas concentrations to be observed without interference from surface features. Moisture in the layer extending from about 15,000 ft to 40,000 ft altitude shows up as a lighter color then areas which are drier, which show up darker. This allows one to see moisture in the atmosphere, not just cloud patterns where moisture has condensed. One can then see circulation patterns and other features even when clouds are not present.

Because organized atmospheric disturbances usually have large regions of upward (or downward) motion and consequent moistening (or drying), the water vapor data can often be used to locate and define synoptic features such as shortwave troughs, ridges, jet streams, etc.

[FONT=&quot]- bill[/FONT]

 

[Alan Switzer]

What would a short wave trough look like on water vapor imagery?

 

[Bill Schintler]

What would a short wave trough look like on water vapor imagery?

Right now (4 PM CDT, 07/21/07), several weak shortwaves are rounding the central US ridge and diving into the Upper-Midwest.

http://weather.msfc.nasa.gov/cgi-bin/post-goes

Go to Water Vapor imagery. Select animation and click northwest Iowa on the map. It helps to speed the animation up. Look for lighter areas with cyclonic rotation. The first of several waves embedded in northwesterly upper-flow is shifting through IL while a second wave is approaching northeastern IA. With dry and stable conditions in these areas, no weather is occurring other then some thin cirrus. Further upstream, stronger shortwave energy is pushing to the east along the SD/ND border. Later tonight, lift from this feature will assist in the genesis of a convective complex as a LLJ develops and transports moisture north over a developing WF. Storms will develop in eastern and northeastern ND after 10 PM CDT, and the complex will expand to the southeast and track through northern MN overnight.

[FONT=&quot]- bill[/FONT]