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Description

WARNING: To users of the derived product “co_mmr_midtrop” (carbon monoxide mass mixing ratio to dry air [kg/kg] at ~500 hPa). This variable has a significant bias due to a conversion error: the molecular weight of carbon dioxide (CO2, 44.01 g/mol) was used instead of carbon monoxide (CO, 28.01 g/mol). To correct, simply multiply “co_mmr_midtrop” by 28.01/44.01. Alternatively, derive a profile of mass mixing ratio from scratch using the retrieved column density values (“mol_lay/co_mol_lay”) in the Level 2 files. For further questions or concerns please contact the Sounder SIPS at: sounder.sips@jpl.nasa.gov

The CLIMCAPS (Community Long-term Infrared Microwave Coupled Product System) algorithm is used to analyze data from the AIRS (Atmospheric Infrared Sounder) and AMSU (Advanced Microwave Sounding Unit). The AIRS instrument is a grating spectrometer (R = 1200) aboard the second Earth Observing System (EOS) polar-orbiting platform, EOS Aqua. The AIRS in combination with the AMSU constitutes an innovative atmospheric sounding group of infrared and microwave sensors. The AIRS Standard Retrieval Product consists of retrieved estimates of cloud and surface properties, plus profiles of retrieved temperature, water vapor, ozone, carbon monoxide and methane. The temperature profile vertical resolution is 100 levels total between 1100 mb and 0.1 mb, while moisture profile is reported at atmospheric layers between 1100 mb and 300 mb. The horizontal resolution is 50 km.

The CLIMCAPS algorithm uses an Optimal Estimation methodology and uses an a-priori first guess to start the process. A CLIMCAPS sounding is comprised of a set of parameters that characterizes the full atmospheric state and includes a variety of geophysical parameters derived from the CrIMSS data. These include surface temperature and infrared emissivity; full atmosphere profiles of temperature, water vapor and ozone; infrared effective cloud top characteristics; carbon monoxide, methane, carbon dioxide, sulfur dioxide, nitrous oxide, and nitric acid.

This monthly one degree latitude by one degree longitude level-3 product starts with level-2 retrieval products applying the specific quality control (QC) methodology. Specific QC accepts profile level from the top of the atmosphere down to the level where the QC determines that it is still good. Below this level, the data is rejected.

Product Summary

Platforms
Aqua
Instruments
AIRS ,
AMSU-A
Spatial Extent

N: 90 S: -90 E: 180 W: -180

Geographic Region
GLOBAL
Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
2002-08-31 to 2016-09-26
Data Partner
Goddard Earth Sciences Data and Information Services Center (formerly Goddard DAAC), Terrestrial Information Systems Laboratory, Earth Sciences Division, Science and Exploration Directorate, Goddard Space Flight Center, NASA (NASA/GSFC/SED/ESD/TISL/GESDI
Concept ID
C1693440838-GES_DISC
Data State
ACTIVE
Number of Files/Granules
169
Processing Level
3
Published
Updated
Science Keywords
Tropospheric Ozone ,
Tropopause ,
Methane ,
Atmospheric Ozone ,
Surface Pressure ,
Outgoing Longwave Radiation ,
Surface Temperature ,
Air Temperature ,
Upper Air Temperature ,
Layered Precipitable Water ,
Total Precipitable Water ,
Water Vapor Profiles ,
Cloud Fraction ,
Cloud Top Pressure ,
Cloud Top Temperature ,
Cloud Vertical Distribution ,
Precipitation Rate ,
Emissivity ,
Skin Temperature ,
Sea Surface Temperature

Citation

Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.

Copy Citation

Barnet, C. (2021). Sounder SIPS: AQUA AIRS IR + MW Level 3 CLIMCAPS : Specific Quality Control Gridded Monthly V2 [Data set]. NASA Goddard Earth Sciences Data and Information Services Center. https://doi.org/10.5067/I9AJNY3T70UC Date Accessed: 2025-12-14

Documents

READ-ME

ALGORITHM THEORETICAL BASIS DOCUMENT (ATBD)

Variables

Variables are a set of physical properties whose values determine the characteristics or behavior of something. For example, temperature and pressure are variables of the atmosphere. Parameters and variables can be used interchangeably. Variable level attributes provide individual information for each variable.

The Name in this table is the variable name. Fill value indicates missing or undefined data points in a variable. Valid range is the range of values the variable can store. Scale factor is used to increase or decrease the size of an object and can be used to correct for distortion. For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor
air_pres pressure levels Pa float32 9.9692099683869E+36 N/A N/A
air_pres_h2o H2O vapor pressure levels Pa float32 9.9692099683869E+36 N/A N/A
air_temp air temperature profile on 100 levels Kelvin float32 9.9692099683869E+36 N/A N/A
ch4_mmr_midtrop Methane mass mixing ratio to dry air at 40000 Pa, near the peak of sensitivity kg / kg float32 9.9692099683869E+36 N/A N/A
cld_frac effective cloud fraction 1 float32 9.9692099683869E+36 N/A N/A
cld_pres_lay coarse cloud pressure layers Pa float32 9.9692099683869E+36 N/A N/A
cld_pres_lay_bnds min and max pressure for coarse cloud layers Pa float32 9.9692099683869E+36 N/A N/A
cld_pres_lay_lbl Altitude labels for cloud pressure layers N/A OTHER N/A N/A N/A
cld_top_pres cloud top pressure Pa float32 9.9692099683869E+36 N/A N/A
co2_vmr_uppertrop Carbon Monoxide volume mixing ratio to dry air between 20,000-50,000 Pa, near the peak of sensitivity m3 / m3 float32 9.9692099683869E+36 N/A N/A
co_mmr_midtrop Carbon Monoxide mass mixing ratio to dry air at 50000 Pa, near the peak of sensitivity kg / kg float32 9.9692099683869E+36 N/A N/A
dof/air_temp_dof The trace of the averaging kernel matrix as a measure of the number of pieces of information about the air temperature profile provided by the physical retrieval step. 1 float32 9.9692099683869E+36 N/A N/A
dof/ch4_dof The trace of the averaging kernel matrix as a measure of the number of pieces of information about the methane profile provided by the physical retrieval step. 1 float32 9.9692099683869E+36 N/A N/A
dof/co2_dof The trace of the averaging kernel matrix as a measure of the number of pieces of information about the carbon dioxide profile provided by the physical retrieval step. 1 float32 9.9692099683869E+36 N/A N/A
dof/co_dof The trace of the averaging kernel matrix as a measure of the number of pieces of information about the carbon monoxide profile provided by the physical retrieval step. 1 float32 9.9692099683869E+36 N/A N/A
dof/h2o_vap_dof The trace of the averaging kernel matrix as a measure of the number of pieces of information about the water vapor profile provided by the physical retrieval step. 1 float32 9.9692099683869E+36 N/A N/A
dof/o3_dof The trace of the averaging kernel matrix as a measure of the number of pieces of information about the ozone profile provided by the physical retrieval step. 1 float32 9.9692099683869E+36 N/A N/A
dof/surf_temp_dof The trace of the averaging kernel matrix as a measure of the number of pieces of information about the surface provided by the physical retrieval step. 1 float32 9.9692099683869E+36 N/A N/A
gp_hgt Geopotential is the sum of the specific gravitational potential energy relative to the geoid and the specific centripetal potential energy. Geopotential height is the geopotential divided by the standard acceleration due to gravity. m float32 9.9692099683869E+36 N/A N/A
h2o_vap_tot total precipitable water vapor kg / m2 float32 9.9692099683869E+36 N/A N/A
lat Degrees latitude degrees_north float32 9.9692099683869E+36 N/A N/A
lat_bnds min and max degrees for each longitude grid cell degrees_north float32 9.9692099683869E+36 N/A N/A
lay_cld_frac coarse layer effective cloud fraction 1 float32 9.9692099683869E+36 N/A N/A
lon Degrees longitude degrees_east float32 9.9692099683869E+36 N/A N/A
lon_bnds min and max degrees for each longitude grid cell degrees_east float32 9.9692099683869E+36 N/A N/A
nobs/air_temp_nobs air_temp number of observations 1 float32 9.9692099683869E+36 N/A N/A
nobs/ch4_mmr_midtrop_nobs ch4_mmr_midtrop number of observations 1 float32 9.9692099683869E+36 N/A N/A
nobs/cld_frac_nobs cld_frac number of observations 1 float32 9.9692099683869E+36 N/A N/A
nobs/cld_top_pres_nobs cld_top_pres number of observations 1 float32 9.9692099683869E+36 N/A N/A
nobs/co2_vmr_uppertrop_nobs co2_vmr_uppertrop number of observations 1 float32 9.9692099683869E+36 N/A N/A
nobs/co_mmr_midtrop_nobs co_mmr_midtrop number of observations 1 float32 9.9692099683869E+36 N/A N/A
nobs/gp_hgt_nobs gp_hgt number of observations 1 float32 9.9692099683869E+36 N/A N/A
nobs/h2o_vap_tot_nobs h2o_vap_tot number of observations 1 float32 9.9692099683869E+36 N/A N/A
nobs/nobs_max Maximum number of observations including those for which no value was retrieved. Can be used with *_nobs to calculate yield. 1 float32 9.9692099683869E+36 N/A N/A
nobs/o3_tot_nobs o3_tot number of observations 1 float32 9.9692099683869E+36 N/A N/A
nobs/prior_surf_pres_nobs prior_surf_pres number of observations 1 float32 9.9692099683869E+36 N/A N/A
nobs/rel_hum_nobs rel_hum number of observations 1 float32 9.9692099683869E+36 N/A N/A
nobs/spec_hum_nobs spec_hum number of observations 1 float32 9.9692099683869E+36 N/A N/A
nobs/surf_air_temp_nobs surf_air_temp number of observations 1 float32 9.9692099683869E+36 N/A N/A
nobs/surf_alt_nobs surf_alt number of observations 1 float32 9.9692099683869E+36 N/A N/A
nobs/surf_ir_emis_nobs surf_ir_emis number of observations 1 float32 9.9692099683869E+36 N/A N/A
nobs/surf_temp_nobs surf_temp number of observations 1 float32 9.9692099683869E+36 N/A N/A
nobs/tpause_pres_nobs tpause_pres number of observations 1 float32 9.9692099683869E+36 N/A N/A
o3_tot Total column ozone. (Multiply by 4.670e5 to convert to Dobson Units from kg m^-2) kg / m2 float32 9.9692099683869E+36 N/A N/A
obs_time_tai93 Nominal midtime for observations included in grid seconds since 1993-01-01 00:00 float64 9.9692099683869E+36 N/A N/A
obs_time_tai93_bnds Nominal start and end time for observations included in grid seconds since 1993-01-01 00:00 float64 9.9692099683869E+36 N/A N/A
obs_time_utc Nominal midtime for observations included in grid as an array of integers: year, month, day, hour, minute, second, millisec, microsec N/A uint16 65535 N/A N/A
orbit_pass Nominal solar time when the spacecraft passes over the equator. Orbit pass bounds are defined by closest approach of the spacecraft to the poles. hours float32 9.9692099683869E+36 N/A N/A
prior_surf_pres surface pressure from forecast for observations Pa float32 9.9692099683869E+36 N/A N/A
rel_hum relative humidity over equilibrium phase 1 float32 9.9692099683869E+36 N/A N/A
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