README.md

In SantanderMetGroup/convertR: A climate4R Package for Unit Conversion and Variable Derivation

convertR: A climate4R package for unit conversion and variable derivation

convertR is an R package performing unit conversion and variable derivation using the climate4R Common Data Model.

Installation and requirements

Physical quantity handling is done via the Unidata's UDUNITS-2 software libraries, tailoring the functionalities of the R package udunits2 to the climate4R framework. Thus, the C-based UDUNITS-2 package must be installed in your system prior to package installation (link to installation instructions).

Then, install_github can be used:

devtools::install_github("SantanderMetGroup/convertR")

Unit conversion

The function udConvertGrid is used for unit conversion. An example follows:

library(convertR)
data("ps.iberia")
transformeR::getGridUnits(ps.iberia)
## [1] "Pascals"
range(ps.iberia$Data)
## [1]  86657.5 105690.0
ps.mmHg <- udConvertGrid(ps.iberia, new.units = "mmHg")
transformeR::getGridUnits(ps.mmHg)
## [1] "mmHg"
range(ps.mmHg$Data)
## [1] 649.9846 792.7401

Derivation of physical quantities

In the following table the available variable derivations are summarized, including the input variables. The nomenclature of the input variables to calculate the derivations is according to the climate4R vocabulary (see loadeR::c4R.vocabulary())

The (*) symbol indicates that the function is planned but not yet available.

| function | Definition | psl | ps | tas | dpds | tdps | zgs | huss | hurs | rsds | rlds | |----------- |------------------------------------------------- |----- |---- |----- |------ |------ |---- |------ |------ |------ |------ | | psl2ps | Sea-level pressure to surface pressure | X | | X | | | X | | | | | | ps2psl | Surface pressure to sea-level pressure | | X | X | | | X | | | | | | rad2cc | Radiation to cloud cover | | | | | | | | | X | X | | huss2hurs | Specific humidity to relative humidity | | X | X | | | | X | | | | | hurs2huss | Relative humidity from specific humidity | | X | X | | | | | X | | | | tas2ws | Saturation vapor pressure from temperature | | X | X | | | | | | | | | hurs2w | Water vapor mixing ratio from relative humidity | | X | X | | | | | X | | | | dpds2hurs* | Relative humidity from dew-point depression | | X | X | X | | | | | | | | tdps2hurs | Relative humidity from dew-point temperature | | | X | | X | | | | | | | hurs2tdps | Dew-point temperature from relative humidity | | | X | | | | | X | | | | huss2pvp | Partial vapor pressure from specific humidity | | X | | | | | X | | | |

The input variables do not require to be in specific units, as all the necessary unit conversions are internally undertaken by the unit converter utility.

SantanderMetGroup/convertR documentation built on June 30, 2023, 3:03 a.m.