Re: Ascent Rates of Sounding Balloons

MET wrote: 
Thank you Dave for this information. I actually did already come across
this link and others giving 'general' information on ascent rates like
those given by the balloon manufactureres. The available information is
generally either the ascent rate at the beginning of the sounding or an
approx. mean value for the complete sounding.

The Internet page http://www.eeps.com/zoo/cages/Radiosonde.html gives
from a sounding the time when a height level was reached. These data
indicate that the mean ascent rate is decelerating in the first 3000m
from 5.5m/s to 4m/s and then starting to accelerate slowly to reach
4.7m/s at 18km height. (Note that all these values are approximate.) Is
this behaviour typically? Without this information I would have asumed
that the balloon would be decelerating before bursting.

Marcel Tschudin

Marcel,

I can't say for sure about what is typical. If you are in heavy rain (which I am often launching in) the balloon can even begin to "porpoise" or descend due to heavy wet snow accumulation at the melting level, descend until the snow sloughs off, then begin an ascent again to attempt to punch through the snow. We increase the amount of helium in our balloons if we think this will happen, thus giving greater ascent rates...6-7m/s for example, so there is less time for snow and ice to accumulate. Hope that helps

Dave White
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