20000118: unit errors in decoded sounding data (fwd)

Paul,

UWND/VWND is meters per second. UKNT/VKNT are knots. If you want units
in knots, you need to use the appropriate parameter.

The units column label is not from GEMPAK, but apparently something you
have tacked on. You need to maintain that label to be consistent
with the parameter usage above.

Steve Chiswell
Unidata User Support



>From: Paul Ruscher <address@hidden>
>Organization: .
>Keywords: 200001181842.LAA08774

>Gempak decoding problem here, perhaps?  I've checked and I think Chris is
>correct - happens in other soundings, too.  Paul Ruscher
>
>---------- Forwarded message ----------
>Date: Tue, 18 Jan 2000 15:10:32 +0000 (GMT)
>From: Chris Walcek <address@hidden>
>To: address@hidden, address@hidden
>Subject: unit errors in decoded sounding data
>
>To whom it may concern,
>
>I regularly download and use decoded soundings
>from your web pages. There is an error in the
>units of the wind speeds presented in these tabulated
>data. For example, here is a excerp of Tuscon AZ
>0Z sounding, 18 January 2000
>
>PRESS     WDIR    WSPD    UWND    VWND
> MB        DEG    KNTS    KNTS    KNTS
>-----    -----    ----    -----   ----- 
>929.0    310.0     4.0    1.6    -1.3 
>925.0    310.0     4.0    1.6    -1.3
>
>
>First, wind directions and speeds are presented
>in degrees and "KNTS". Speed I assume is in
>nautical miles per hour.
>
>Later, U(west-east) and V(south-north) winds
>are tabulated, also in units of KNTS. However,
>when I take the square root of the sum of
>the squares of U and V (sqrt(U^2 + V^2) one
>does not get the original wind speed. In fact
>there is a discrepancy of a factor of 1.94 which
>is precisely the conversion of nautical miles per
>hour to meters per second.
>
>It looks like the units of U and V are WRONG and
>should be in meters per second (m/s)????
>
>Is this correct? If so please change the table
>headings appropriately. Other explanations
>of this discrepancy are possible.
>
>Thanks
>Chris Walcek
>
>(beware the Mars pathfinder fiasco where 
>sloppy unit conversions were responsbile for
>disaster!!)
>
>