GitHub

Variable Types in ERA5Reanalysis.jl

In order to download data from the Climate Data Store, we need to specify at least a variable to download. This variable can be one found directly from CDS, or it can be a custom user-defined variable (in which case it has to be calculated by the user). Information regarding this variable will be loaded into an ERA5Variable.

ERA5Reanalysis.ERA5Variable — Type
ERA5Variable

Abstract supertype for ERA5 variables, with the following subtypes

SingleLevel   <: ERA5Variable
PressureLevel <: ERA5Variable

All ERA5Variable Types contain the following fields:

  • ID : The variable ID, that is also the identifier in the NetCDF files
  • name : The full-name of the variable
  • long : The variable long-name, which is used to specify retrievals from CDS
  • dataset : The full-name of the variable
  • units : The units of the variable

All PressureLevel Types contain the following fields:

  • hPa : The pressure level (in hPa) of the pressure-variable of interest
source

SingleLevel and PressureLevel variables

There are two main ERA5Variable types in ERA5 reanalysis:

  • SingleLevel variables, such as surface temperature, or total cloud cover, that are provided in the (lon,lat) space
  • PressureLevel variables, such as atmospheric temperature, or specific humidity, that are provided in the (lon,lat,pressure) space
ERA5Reanalysis.SingleLevel — Type
SingleLevel <: ERA5Variable

Abstract supertype for Single-Level variables, with the following subtypes:

SingleVariable <: SingleLevel
SingleCustom   <: SingleLevel
source
ERA5Reanalysis.PressureLevel — Type
PressureLevel <: ERA5Variable

Abstract supertype for Single-Level variables, with the following subtypes:

PressureVariable <: PressureLevel
PressureCustom   <: PressureLevel
source

Custom ERA5Variables

Each of these supertypes are further broken down into XXVariable and XXCustom subtypes, where XXVariable represents a variable that is available directly from CDS, and XXCustom variables are user-defined variables. XXCustom variables therefore cannot be downloaded - trying to do so will result in a method error - and can only be calculated from existing variable data.

ERA5Reanalysis.SingleCustom — Type
SingleCustom <: SingleLevel

Subtype for custom user-defined Single-Level variables, which can only be calculated and not downloaded from the Climate Data Store.

source
ERA5Reanalysis.PressureCustom — Type
PressureCustom <: PressureLevel

Subtype for custom user-defined Pressure-Level variables which can only be calculated and not downloaded from the Climate Data Store.

source