<div dir="ltr">Sujit,<div><br></div><div>The GFS product you list does not have a spin-up time. It was already warmed by prior model runs in production. You could use the f000 file (first time step) or the analysis file (anl). I'm not exactly sure what the WRF model prefers. I can't say exactly how many time steps it takes before the error grows "high"...we normally describe that based on forecast hours. You can review the performance metrics of the GFS at this webpage:</div><div><br></div><div><a href="http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/" target="_blank">http://www.emc.ncep.noaa.gov/<wbr>gmb/STATS_vsdb/</a><br></div><div><br></div><div>Of interest to you would be the dieoff curves, which are viewable after choosing "Anomaly Correlation" on the left. Those plots are based on forecast hour. An anomaly correlation less than 0.6 is considered low skill.</div><div><br></div><div>In the future please contact our Monsoon Desk for NCEP model inquires. All inquires from IITM are coordinated through that desk. I have cc'd our Monsoon Desk contact (Partha Bhattacharjee) to let him know of your inquiry.</div><div class="gmail_extra"><br clear="all"><div><div class="m_7573992666860966141gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><br>Kate Howard<br>NOAA/NWS/NCEP/EMC GCWMB<br>Global Forecast System (GFS)<br></div></div></div></div></div></div></div>
<br><div class="gmail_quote">On Fri, Feb 24, 2017 at 1:19 AM, Sujit Maji <span dir="ltr"><<a href="mailto:sujit.cat@tropmet.res.in" target="_blank">sujit.cat@tropmet.res.in</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Dear Sir/Madam,<br>
<br>
I want to use GFS product gfs.tCCz.pgrb2.0p50.fFFF (from <a href="http://www.nco.ncep.noaa.gov/pmb/products/gfs/" rel="noreferrer" target="_blank">http://www.nco.ncep.noaa.gov/p<wbr>mb/products/gfs/</a>) as meteorological inpout to forecasting system using WRF-Chem. I have following queries.<br>
<br>
Is the above mentioned GFS output product contain any spin-up time ?<br>
<br>
Can I use GFS output data from time 000 (gfs.tCCz.pgrb2.0p50.f000) as input to WRF ?<br>
<br>
or, I have to use data after the the spin-up time (e.g. if spin-up time is 24 hrs, then i will use data from gfs.tCCz.pgrb2.0p50.f024).<br>
<br>
How many time steps of this data product is useful before the error grows high ?<br>
<br>
Thanks and regards,<br>
Sujit Maji<br>
</blockquote></div><br></div></div>