Jump to content
GMS, SMS, and WMS User Forum
Sign in to follow this  
Hila

Mass calculation in MT3D

Recommended Posts

Hi,

I wanted to ask about mass calculation in MT3D:

In my model I defined units as g for mass and ppb for conc.

I checked the MAS file and the "Total mass in aquifer" seemed very high than what I expected (I guess about two orders of magnitude). I changed the mass units to Kg and run the model again, and the MAS file looks EXACTLY as the previous file.

Can someone show me how mass calculation is performed ? How is it related to the units I define ?

Thanks in advance,

Hila

Share this post


Link to post
Share on other sites
Hi,

I wanted to ask about mass calculation in MT3D:

In my model I defined units as g for mass and ppb for conc.

I checked the MAS file and the "Total mass in aquifer" seemed very high than what I expected (I guess about two orders of magnitude). I changed the mass units to Kg and run the model again, and the MAS file looks EXACTLY as the previous file.

Can someone show me how mass calculation is performed ? How is it related to the units I define ?

Thanks in advance,

Hila

If you mean that you changed the units in GMS using the Units dialog, than that only affects what units get displayed in the GMS interface. It does not change any of the values you input for the model. The units feature is meant as an aid to remind you what are the proper units you have chosen. It is still up to you to be consistent in your units when you determine the input values. See the wiki page: http://www.xmswiki.com/xms/GMS:Units

Share this post


Link to post
Share on other sites
If you mean that you changed the units in GMS using the Units dialog, than that only affects what units get displayed in the GMS interface. It does not change any of the values you input for the model. The units feature is meant as an aid to remind you what are the proper units you have chosen. It is still up to you to be consistent in your units when you determine the input values. See the wiki page: http://www.xmswiki.com/xms/GMS:Units

So, if the conc. in the units dialog was defined as ppb, and mass as g, what is the unit of "total mass in aquifer" in the MAS file ?

how is it calculated (the numbers in the MAS file are 1E12 - 1E9) ?

Share this post


Link to post
Share on other sites

What you fill in the unit dialog will not influence the calculated mass.

MT3D multiplies concentration with volume, e.g. if the

concentrations you put in the model are micrograms per liter

and the unit of length is meter than the mass is in ug/l x m3 = mg.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Sign in to follow this  

×
×
  • Create New...