20031113: GOES 3.9 um emissive vs. reflective

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Date: Thu, 13 Nov 2003 11:28:19 -0600 (CST)
From: Kristopher Bedka <address@hidden>
To: address@hidden
Subject: GOES 3.9 um emissive vs. reflective
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Hi Mcidaser's

I am trying to use the GOES 3.9 um band to examine convective cloud top 
microphysics (ice vs. water).  After reading several references 
(http://www.chmi.cz/meteo/sat/plumes/), it appears that the reflective 
component of the 3.9 um signal can tell you whether a cloud top is 
composed of liquid or ice.  I would like to use this microphysical 
information within a satellite-based convective storm nowcasting system I 
am developing.  Being that I am not a "satellite person" and come from a 
numerical modelling/mesoscale meteo. background, I do not have the 
expertise to pick out the reflective component from the 3.9 um channel.  
Has anyone here ever had to do this procedure before?  If so, would anyone 
be willing to share their McIDAS/Fortran routines to do this?  I would 
greatly appreciate anyone's expertise in this area.

Thanks,
Kris


- -- 
Kristopher Bedka
Assistant Researcher
SSEC/CIMSS, University of Wisconsin-Madison
1225 West Dayton Street, Room 219
Madison, WI 53706    address@hidden

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Date: Thu, 13 Nov 2003 11:49:13 -0600
From: Rick Kohrs <address@hidden>
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Subject: Re: GOES 3.9 um emissive vs. reflective
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As a good start, you can use IMGOPER to subtract the 11um temperature 
from the 3.9um temperature.  This result is used for fog product and 
cloud over snow.

example:

IMGOPER EASTL/CONUS EASTL/CONUS A/A.1 UNIT=TEMP TEMP BAND=4 2 COEF=1 -2 
SCALE=-100 100 0 255 LATLON=48:12:29    102:34:05

Try the above example for todays 17:15 image and compare the results to 
the visible.  I have not worked extensively with this product so you may 
need to adjust the scaling factors. I did some work with Phil Durkee and 
Chuck Wash at NPGS looking at water droplet size differences off the 
coast of California and we generally adjusted the values for the solar 
zenith angle.

Rick

Kristopher Bedka wrote:

> Hi Mcidaser's
> 
> I am trying to use the GOES 3.9 um band to examine convective cloud top 
> microphysics (ice vs. water).  After reading several references 
> (http://www.chmi.cz/meteo/sat/plumes/), it appears that the reflective 
> component of the 3.9 um signal can tell you whether a cloud top is 
> composed of liquid or ice.  I would like to use this microphysical 
> information within a satellite-based convective storm nowcasting system I 
> am developing.  Being that I am not a "satellite person" and come from a 
> numerical modelling/mesoscale meteo. background, I do not have the 
> expertise to pick out the reflective component from the 3.9 um channel.  
> Has anyone here ever had to do this procedure before?  If so, would anyone 
> be willing to share their McIDAS/Fortran routines to do this?  I would 
> greatly appreciate anyone's expertise in this area.
> 
> Thanks,
> Kris
> 
> 


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