Re: [conduit] Removal of 500 and 1000 hPa height anomaly fields from GFS

Hi Justin,

Thanks for the clarification â I was thinking that the climatology on which the 
anomalies were calculated was not the best current source, so your email 
confirmed that.

Greg, et al.:  my first inclination is to create a climatology based on the 
1981-2010 CFSR that uses an 11-day running mean centered on the present day â

Cheers,

Kevin

_____________________________________________
Kevin Tyle, Systems Administrator
Dept. of Atmospheric & Environmental Sciences
University at Albany
Earth Science 235, 1400 Washington Avenue
Albany, NY 12222
Email: ktyle@xxxxxxxxxx<mailto:ktyle@xxxxxxxxxx>
Phone: 518-442-4578
_____________________________________________

From: Justin Cooke - NOAA Federal [mailto:justin.cooke@xxxxxxxx]
Sent: Wednesday, January 14, 2015 4:35 PM
To: Greg Thompson
Cc: Tyle, Kevin R; conduit@xxxxxxxxxxxxxxxx
Subject: Re: [conduit] Removal of 500 and 1000 hPa height anomaly fields from 
GFS

Kevin, Greg,
Several months ago a user evaluating the parallel output from the GFS had the 
same concerns as you about this parameter no longer being available. We reached 
out to NCEP EMC's Mark Iredell and he gave this reasoning for the parameters 
removal:

"the climatology that had been used to compute geopotential height anomalies 
for the GFS was very old, representing a fairly short timeframe from forty 
years ago or so and had some known biases. Your approach of using reanalysis 
data is a far superior solution. Reanalysis climatology would not only have 
known provenance, it is higher resolution in space and longer averaging in 
time."
As you can tell, his recommendation is to use reanalysis data, just like you 
mentioned Greg.
Sorry for the inconvenience the removal of this parameter is causing.
Justin Cooke
NCEP Central Operations


On Wed, Jan 14, 2015 at 4:17 PM, Greg Thompson 
<gthompsn@xxxxxxxx<mailto:gthompsn@xxxxxxxx>> wrote:

Yes, this is a bit disappointing because I've had that product showing for 
years also.  It can always be re-created from opening some reanalysis product 
that is an average, but the ease of plotting a single 2D field, which hardly 
added any real volume to the files, was made it so attractive.

--Greg Thompson,  NCAR-RAL


On Wed, Jan 14, 2015 at 12:33 PM, Tyle, Kevin R 
<ktyle@xxxxxxxxxx<mailto:ktyle@xxxxxxxxxx>> wrote:
Hi everyone,

With todayâs implementation of the GFS upgrades, the 500 and 1000 hPa height 
anomaly grids are no longer part of the output.  This was advertised in the NWS 
Technical Implementation Notice, so it is not a surprise â but up till now, we 
made use of these grids in our web products.

Does anyone know of another quick-and-easy online source of either anomaly or 
mean grids for these two height levels?  I can put something together via the 
CFSR, but that will take a wee bit of time â

Cheers,

Kevin

_____________________________________________
Kevin Tyle, Systems Administrator
Dept. of Atmospheric & Environmental Sciences
University at Albany
Earth Science 235, 1400 Washington Avenue
Albany, NY 12222
Email: ktyle@xxxxxxxxxx<mailto:ktyle@xxxxxxxxxx>
Phone: 518-442-4578<tel:518-442-4578>
_____________________________________________


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