[Lowfer] D Region Absorption Prediction Map

[hvanesce at comcast.net]

Dex,

Nothing new in my comments below, just confirming what you and John already
found and concluded regarding NOAA D-RAP:

I hadn't used NOAA D-RAP before, so following John's comments and your
comments I explored Jan-Nov 2016 NOAA D-RAP reports to weakly correlate
minimum GOES X-ray flux with non-zero D-RAP reports and used that to find
recent events including:

September 22 at 19:30 ( ~ 2.5E-6 W/cm^2)
http://www.ngdc.noaa.gov/stp/drap/data/2016/01/29/SWX_DRAP20_C_SWPC_20160129
220000_GLOBAL.png

October 16 at 23:00 ( ~ 9E-7 W/cm^2)
http://www.ngdc.noaa.gov/stp/drap/data/2016/10/16/SWX_DRAP20_C_SWPC_20161016
230000_GLOBAL.png

In search of a rough minimum flux level for non-zero D-RAP reports, I
checked NOAA D-RAP reports for six events between January and October 2016
with GOES (1.0A-8.0A) X-ray flux levels ~ 4E-7 W/m^2.
All six events (with flux levels ~ 4E-7 W/cm^2) that I checked showed as 0
dB (black) on NOAA D-RAP.
GOES flux levels since October 17th have been below 4E-7; so the above fits
with what you and John found and concluded.

73,

Jim AA5BW



    

-----Original Message-----
From: Lowfer [mailto:lowfer-bounces at mailman.qth.net] On Behalf Of Dexter
McIntyre W4DEX
Sent: Friday, November 4, 2016 2:27 PM
To: Discussion of the Lowfer (US, European, & UK) and MedFer bands
Subject: Re: [Lowfer] D Region Absorption Prediction Map

listread at lwca.org wrote:
> One would need to check with NOAA to  see if the data are being 
> generated, but it is possible that the graphic is correct.  It has 
> been quite some time now since there has been more than an A-class 
> X-ray flare to generate an absorption event.
>
>   
Apparently you are correct John.  Looks like the last significant flare was
on 24 July 16.  The map archive for that date does show the enhanced D Layer
ionization:

http://www.ngdc.noaa.gov/stp/drap/data/2016/07/24/SWX_DRAP20_C_SWPC_20160724
172300_GLOBAL.png

Dex
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