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20030910: Rainfall Rates

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  • Subject: 20030910: Rainfall Rates
  • Date: Thu, 11 Sep 2003 10:48:47 -0600
>From: mljacobs <address@hidden>
>Organization: UCAR/Unidata
>Keywords: 200309102217.h8AMHeLd023414

>Hello,
>I was wondering if there is a way to get a rainfall rate from using the 
>difference in 1-hour precip. in GEMPAK. The files are updated every 6 min.  
>Resulting in the amount of rainfall in 6 minutes.  I have the level III radar 
>data from NCDC.
>Am I going about this the right way or do you have another suggestion?
>Thanks for your time
>Matt Jacobs (KU)
>

Matt,

The NIDS Level III products are 16 value images and not actual data values.
The 16 values therefore represent a range of precipitation values, so
trying to do mathematical differencing is not likely to be accurate.

The products are generated from the PUP using Z to R relationships
assuming a droplet size distribution), so you can use the reflectivity
product (again these are 16 binned data values) as an approximation to
instantaneous rainfall rate. Otherwise, you would have to do a Z to R 
conversion from level 2 data values.

Steve Chiswell