<div>Hi,<br />I'm trying to display variable 'apcpsfc' from the 3 hr and 1 hr NAM. The resulting images appear to pulsate/accumulate precip every few images then reset only to accumulate again.<br /><br />I've seen the threads in the archive on this issue with HD GFS data, but I'm trying to understand 2 things:<br /><br />1) What is the accumulation period for NAM 1 hr and 3 hr data. I was thinking it was every 3 time steps (i.e. excluding time step 1 / 00 hr), it is 2, 3, 4 then reset and start accumulating again for the next 3 time steps 5, 6 and 7). But that doesnt seem to be the case. <br /><br />2) What does it mean to 'normalize' the data? Westly did something in wgrib2 for HD GFS data to normalize it and I was wondering if that was also applicable to NAM data. What is done to mathmatically to get the data to be valid for just a single timestep?. Can I write something in GRDADS to perform the normalization rather than having to use WGRIB2. <br /><br />Assuming the accumulation theory is correct (that apcpsfc accumulates every three time steps), I've been trying to write code to remove the accumulation by:<br /><br />Display Time = 2<br />Time 3 = Time 3 - Time 2<br />Display Time 3<br />Time 4 = Time 4 - Time 3<br />Display Time 4<br /><br />But it doesnt work. <br /><br />Any help would be appreciated.<br /><br />Thanks,<br />Mark </div>
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<div><span style="font-size: small;">Thanks,<br />Mark</span></div>