[gradsusr] GFS_0p25 and total precip accum
jsc219 at gmail.com
Tue Jun 22 10:37:29 EDT 2021
Hi GrADS Users,
I am having trouble with computing precip accum using just GFS_0p25
from NCEP. The source that I am using is the following:
To compute precip, I'm using:
'define precip = const((apcpsfc/25.4),0,-u)'
I set the following variables:
Then, in the while loop, I am using this equation to subtract 0-6
hours from 0-3 hours (Please note, I only need to do this for GFS):
'define rain = const(precip(t='t') - precip(t='t0'),0,-u)'
This works well for a 3 hour interval of precip (every three hours up
to 10 days).
Next, I am trying to apply a sum to it to get total accumulated precip totals:
'define accum = sum(rain,t=1,t='t')'
For other models like NAM, I use the following since I don't need the
'define accum = sum(precip,t=1,t='t')'
I then do the counter and then end my loop:
t = t+1
t0 = t0+1
I have tried modifying the define accum equation with no luck. If I
use precip in the equation, then I get ridiculous precip totals of 24
inches for 1/2 of the country in 10 days. If I use rain, then I'm not
getting total precipitation, instead I'm getting an interval.
Any suggestions would be greatly appreciated. I suspect that I have
an error in my equation. the correct accum equation.
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