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20031231: SEARCH

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  • Subject: 20031231: SEARCH
  • Date: Wed, 31 Dec 2003 12:59:40 -0700
Jimmy,

To clarify, gdobscnt uses RADIUS, not SEARCH. This program was written
in response to a user support question I had to count the number
of observations within a certain radius. It is not doing objective analysis.
You could estimate this using RADIUS equal to SRAD as defined below.

The SEARCH parameter used in OABSFC is a number (not a distance) used to
determine if the weight contributed by a member is greater than
EXP (-SEARCH). 

In $GEMPAK/source/gemlib/oa/oawfsr.f, you see that the search radius SRAD
is SEARCH * WEIGHT, eg:
SRAD = SEARCH * [ 5.051457 * ( DELTAN * 2. / PI ) ** 2 ]
as documented in the Koch reference.

Steve Chiswell





>From: address@hidden
>Organization: UCAR/Unidata
>Keywords: 200312311856.hBVIuPp2000555

>Hi-
>(Happy Holidays!)
>I have a question about search and radius from oabsfc and gdobscnt.
>In search the units for the search radius are Kilometers? While in 
>gdobscnt the units are in meters. 
>I am attempting to see how many observations contribute to each grid point 
>from my surface file but don't know how to relate search to radius.
>Can you provide any information that might help me?
>I am currently using 20/EX for search and a radius of 60000 meters.
>Thanks very much,
>
>-- 
>James Correia Jr.
>Ph.D. Candidate in Agricultural Meteorology
>Dept. of Agronomy, Iowa State University
>*********************************************
>Email: address@hidden
>Phone: 515-294-5587
>Web: http://www.mesoscale.iastate.edu/jimmyc/
>*********************************************
>"Imagination is more important than knowledge."
>-Einstein
>
>"There is a difference between knowing the path and walking the path"
>-"Morpheus"
>