Radiosonde Issues

[rdale]

Nice study by Bob Maddox and Barry Schwartz at http://www.madweather.com/

Strongly Superadiabatic Lapse Rates Aloft
at Six Upper-Air Sounding Sites​

Bob Maddox and Barry Schwartz
Tucson, Arizona and Boulder, Colorado
Private Consultants​

25 October 2008
http://www.squidinkbooks.com/madweather/pdfs/Strongly Superadiabatic Lapse Rates Aloft.pdf​

BACKGROUND
One aspect of soundings from the new National Weather Service (NWS) Radiosonde Replacement System (RRS – details may be found at www.ua.nws.noaa.gov/RRS.htm and also on posts here during summer 2007) is that, since the thermistor is easily wetted in moist environments, strongly superadiabatic layers aloft (hereafter SSLAs) now appear frequently in the data. This is usually, but not always, due to “wetbulbingâ€￾ – i.e., the rapid cooling that occurs when water/ice evaporate/sublimate from the thermistor.


SUMMARY AND WARNING
There are large numbers of soundings with physically unrealistic data being added to the upper-air archives each month. The NWS quality control procedures are obviously not working. Anyone using these data for research, computations, or statistical analyses needs to understand that there are new and significant problems with the reliability of the data owing to the NWS transition to the Microsonde MKII – GPS sondes.

 

[Chris Nuttall]

I see that they've done several papers on the RRS system. I'll have to take a look at them when I have more time. We use the RRS at AMA. As one of the interns, my shift is centered around the UA flight. I've run into the superadiabatic problem before, but it almost always occurs immediately following release...within the first 2-4 data points.

Dry bias is another big problem with the MKII sondes, but it's pretty well known and documented.