ms_conversions: Convert MacroSheds concentration units and molecular...

In MacroSHEDS/macrosheds: Tools for interfacing with the MacroSheds dataset

Convert MacroSheds concentration units and molecular representations

Description

MacroSheds concentration data are represented in either mass, moles, or equivalents per liter (mg/L, mol/L, or uEq/L, respectively, but note that one variable, "ANC" is represented by default in Eq/L). Use this function to convert among these units. You may also use this function to convert SI prefixes, e.g. mg/L to kg/L, or to convert between molecular and atomic representations for some elements and compounds. For example, nitrate (NO3) can be converted to nitrate-N and vice versa.

Usage

ms_conversions(
  d,
  convert_units_from = "mg/l",
  convert_units_to,
  convert_molecules
)

Arguments

d	data.frame. A data.frame in MacroSheds format (see details), containing stream_chemistry or precip_chemistry data. A tibble in MacroSheds format is generated by ms_load_product().
convert_units_from	(named) character vector. If named, names are variable_codes and values are the units of those variables (see ms_load_variables()). Omit variables that don't need to be converted. Or provide a single unit as an unnamed character if all variables are in the same unit.
convert_units_to	(named) character vector. If named, names are variable_codes and values are the units those variables should be converted to (see ms_load_variables()). Omit variables that don't need to be converted. Or provide a single unit as an unnamed character if all variables will be converted to the same unit.
convert_molecules	character vector. Molecules that will be converted according to the atomic mass of their main constituent. For example, this can be used to convert NO3-N to NO3, or NO3 to NO3-N. See details.

Details

In MacroSheds, concentrations of the following molecules are represented according to the atomic mass of their primary constituent atom: NO3, NO2, NO3_NO2 (variable code for NO3 + NO2), NH4, NH3, NH3_NH4, SO4, SiO2, SiO3, PO4, orthophosphate. For example, if MacroSheds retrieved SiO2 concentration in mg/L from some domain, we converted it to mg/L SiO2-Si (coded as "SiO2_Si"). You could use this function to convert it back to SiO2 by setting convert_molecules = 'SiO2_Si'. You could then convert it to SiO2-Si again by setting convert_molecules = 'SiO2. See examples for more.

Default units for all variables can be seen via ms_load_variables().

MacroSheds format (only var and val columns required as inputs to this function):

header value	column_definition
date	Date in YYYY-mm-dd
site_code	A unique identifier for each MacroSheds site, identical to primary source site code where possible. See ms_load_sites().
grab_sample	Boolean integer indicating whether the observation was obtained via grab sample or installed sensor. 1 = TRUE (grab sample), 0 = FALSE (installed sensor).
var	Variable code. See ms_load_variables().
val	Data value. See ms_load_variables() for units.
ms_status	Boolean integer. 0 = clean value. 1 = questionable value. See "Technical Validation" section of the MacroSheds data paper for details.
ms_interp	Boolean integer. 0 = measured or imputed by primary source. 1 = interpolated by MacroSheds. See "Temporal Imputation and Aggregation" section of the MacroSheds data paper for details.
val_err	The combined standard uncertainty associated with the corresponding data point, if estimable. See "Detection Limits and Propagation of Uncertainty" section of the MacroSheds data paper for details.

Value

returns a tibble in MacroSheds format, containing concentration data converted to new units.

Author(s)

Spencer Rhea

Mike Vlah, [e-mail]

Wes Slaughter

See Also

ms_load_product(), ms_load_variables()

Examples

ms_root = 'data/macrosheds'
ms_download_core_data(macrosheds_root = ms_root,
                      domains = 'hbef')
d <- ms_load_product(macrosheds_root = ms_root,
                     prodname = 'stream_chemistry',
                     domains = 'hbef',
                     filter_vars = c('NO3_N', 'Na', 'Mg', 'SO4_S'))

# Convert all variables from mg/L to ug/L (micrograms per liter)
converted_data <- ms_conversions(d = d,
                                 convert_units_from = 'mg/l',
                                 convert_units_to = 'ug/l')

# Convert mg/L NO3-N to mg/L NO3
converted_data <- ms_conversions(d = d,
                                 convert_units_from = 'mg/l',
                                 convert_units_to = 'mg/l',
                                 convert_molecules = 'NO3_N')

# Convert from mg/L to mmol/L
converted_data <- ms_conversions(d = d,
                                 convert_units_from = 'mg/l',
                                 convert_units_to = 'mmol/l')

# Convert from mg/L to mEq/L
converted_data <- ms_conversions(d = d,
                                 convert_units_from = 'mg/l',
                                 convert_units_to = 'meq/l')

# Convert variables to different units
converted_data <- ms_conversions(d = d,
                                 convert_units_from = c('NO3_N' = 'mg/l',
                                                        'Na' = 'mg/l',
                                                        'Mg' = 'mg/l',
                                                        'SO4_S' = 'mg/l'),
                                 convert_units_to = c('NO3_N' = 'meq/l',
                                                      'Na' = 'ug/l',
                                                      'Mg' = 'umol/l',
                                                      'SO4_S' = 'g/l'))

MacroSHEDS/macrosheds documentation built on Oct. 30, 2024, 11:15 a.m.