select output when calculating alkalinity

[Ran He]

Hi Parkhurst,

I was trying to use the package in R to calculate the alkalinity using the equation HCO3 + 2*CO3 + OH - H

I have writen as this way, is it right for the output of these four species? Thank you

Code: [Select]

      'SELECTED_OUTPUT       ',
      '  -high precision   TRUE',
      '  -molalities   HCO3- CO3-2 H+ OH-'  # Track carbonate species for alkalinity calculation
    )
   
    phrRunString(input)
    output <- phrGetSelectedOutput()
   
    # Calculate alkalinity from carbonate species (carb_alk = [HCO3-] + 2[CO3-2])
    hco3 <- output$n1$m_HCO3.
    co3 <- output$n1$m_CO3.2
    H <- output$n1$m_H.
    OH <- output$n1$m_OH
   
    # Calculate alkalinity in mmol/kgw
    # Note: Converting from molalities to mmol/kgw
    Alkalinity[nn, mm] <- hco3 * 1000 + 2 * co3 * 1000 - H *1000+OH*1000

[dlparkhurst]

I don't know R well enough to know if your code is correct. It looks like you have the right concept.

However, the alkalinity may contain more species than you have specified, for instance H3SiO4, or H2BO3-. The complete alkalinity is available with

Code: [Select]

SELECTED_OUTPUT; -alkalinity trueThe column name will be Alk.

In addition, you can print all of the species that contribute to alkalinity in a solution with the following:

Code: [Select]

PRINT; -alkalinity true
An additional block will appear in the output file that lists all of the species and their contribution to the alkalinity.