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Use absolute values for flux #24

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dnorgaard-usgs opened this issue Dec 15, 2017 · 1 comment

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commented Dec 15, 2017

The final flux value shouldn't be negative. Check with Swedes on this.

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commented Dec 21, 2017

On Thu, Dec 21, 2017 at 12:23 AM, Santiago Arellano wrote:
Hi,

I agree that the final reported value should be positive for both flux and plume width.

There is a file generated with the program, called ‘FluxLog’ that records the increments of the total flux along the route. This one has positive or negative values for the reasons already explained. I guess this file is used by the program for the calculations, but it lacks a header or any sort of explanation for a user to understand what it means. Maybe this could be modified somehow.

Best regards,

Santiago.

From: Kern, Christoph
Sent: den 20 december 2017 19:29
To: Bo Galle
Cc: Norgaard, Diana ; Santiago Arellano
Subject: Re: Flux calc/Plume width

Dear Bo and Diana

Of course it's true that we need to keep the sign during the integration of each segment of the traverse to avoid problems e.g. caused by serpentine roads. However, it would be possible to take the absolute value of the final flux before it is displayed in the software.

I initially thought this was of minor concern, but I have recently gotten several questions from people about the negative flux. It seems that the negative sign is throwing people off, making them not believe their results, or at least causing unnecessary confusion. I recommend we display the absolute value of the final result (unless I am overlooking something here).

Best regards

Christoph

On Wed, Dec 20, 2017 at 2:45 AM, Bo Galle wrote:

Dear Diana

It should be left as it is. Sometimes, for example in driving on a serpentine road up a mountain, you keep going back and forth through the plume. Then having different sign depending on traverse direction is necessary, to avoid counting the same plume twice. Thus, depending on traverse direction, the total flux may be positive or negative. At the end of course the value is always positive.

I hope this was not too confusing...

Best Regards and Merry Christmas,

Bo

Från: Norgaard, Diana
Skickat: den 15 december 2017 20:14
Till: Bo Galle; Santiago Arellano
Kopia: Kern, Christoph
Ämne: Flux calc/Plume width

Hi,

I noticed that the flux calculations and plume width can be negative at times. Christoph explained why, but felt the final value should be positive. He wanted me to check with you guys first though before making this change in case there's a reason to leave it as is.

thanks,

Diana

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