Primary observations and derived variables

On this page you will find tables that detail the primary CLIMCAPS atmospheric observations and variables derived from the CLIMCAPS retrieval.

CLIMCAPS primary variables

CLIMCAPS retrieves multiple Earth surface, cloud and atmospheric state variables from infrared and microwave measurements using Optimal Estimation inversion (Rodgers, 2000). An overview of the CLIMCAPS flowchart is available in this user guide, and a more detailed discussion is available in Smith and Barnet (20192020). CLIMCAPS products can be accessed, downloaded and visualized in Earthdata and WorldView

In Table 1, we show the primary atmospheric observations that are available in the CLIMCAPS netCDF files, their respective fieldname inside the file, and their vertical level or layer grid. 

Temperaturewater vaporozonecarbon dioxidecarbon monoxide, and cloud products have their own individual user guides. We recommend reading the individual product guides prior to using them in your research.

Table 1: List of atmospheric variables CLIMCAPS retrieves from the cloud cleared radiances

Retrieved Variable

Units

Fieldname

Vertical grid

Temperature

Kelvin

air_temp

mw_air_temp

air_pres

Water Vapor

molec/cm2

h2o_vap_mol_lay

mw_h2o_vap_mol_lay

air_pres_lay

Ozone

molec/cm2

o3_mol_lay

air_pres_lay

Carbon Dioxide

mol/mol

co2_vmr

air_pres

Carbon Monoxide

molec/cm2

co_mol_lay

air_pres_lay

Cloud fraction

%

cld_frac

n/a

Cloud liquid water

molec/cm2

mw_h2o_liq_mol_lay

air_pres_lay

Cloud top pressure

Pa

for_cld_top_pres_2lay

n/a

Methane

molec/cm2

ch4_mol_lay

air_pres_lay

Nitric Acid

molec/cm2

hno3_mol_lay

air_pres_lay

Nitrous Oxide

molec/cm2

n2o_mol_lay

air_pres_lay

Sulphur Dioxide

molec/cm2

so2_mol_lay

air_pres_lay

Surface emissivity

n/a

surf_ir_emis

surf_mw_emis

n/a

Surface reflectivity

n/a

surf_ir_refl

surf_mw_emis

n/a

Surface temperature

Kelvin

surf_temp

mw_surf_temp

n/a

CLIMCAPS derived variables

The CLIMCAPS netCDF files have several useful derived parameters, which are shown in Table 2. Derived variables are calculated from retrieved variables and may be useful for certain applications.

Table 2: List of variables derived from CLIMCAPS V2 retrieval variables (Table 1). This is not a complete list as the product file contains many derived variables. For a full list, please see the CLIMCAPS V2 product user guide.

Derived Variables

Units

Fieldname

Vertical grid

Methane mass mixing ratio at 400 hPa

kg/kg

ch4_mmr_midtrop

n/a

Cloud top temperature

Kelvin

cld_top_temp

n/a

Carbon monoxide mass mixing ratio at 500 hPa

kg/kg

co_mmr_midtrop

n/a

Geopotential height

meter

gp_hgt

air_pres

Ozone mass mixing ratio

kg/kg

o3_mmr

air_pres

Relative humidity

%

rel_hum

air_pres_h2o

Specific humidity

kg/kg

spec_hum

mw_spec_hum

air_pres_h2o

Total column cloud liquid water

Kg/m2

h2o_liq_tot

n/a

Total column ozone

kg/m2

o3_tot

n/a

Total precipitable water

kg/m2

h2o_vap_tot

mw_h2o_vap_tot

n/a

References

  • Smith, N. and Barnet, C. D.: Uncertainty Characterization and Propagation in the Community Long-Term Infrared Microwave Combined Atmospheric Product System (CLIMCAPS), Remote Sensing, 11(10), 1227, doi:10.3390/rs11101227, 2019.
  • Smith, N. and Barnet, C. D.: CLIMCAPS observing capability for temperature, moisture, and trace gases from AIRS/AMSU and CrIS/ATMS, Atmos. Meas. Tech., 13, 4437–4459, https://doi.org/10.5194/amt-13-4437-2020, 2020