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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). The AIRS instrument is a grating spectrometer (R = 1200) aboard the second Earth Observing System (EOS) polar-orbiting platform, EOS Aqua. The AIRS CLIMCAPS 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.

An AIRS level 2 granule has been set as 6 minutes of data, 30 footprints cross track by 45 lines along track. There are 240 granules per day, with an orbit repeat cycle of approximately 16 day.

Product Summary

Platforms
Aqua
Instruments
AIRS
Spatial Extent

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

Location
GLOBAL
Coordinate System
GEODETIC
Granule Spatial Representation
GEODETIC
Temporal Extent
2002-08-30 to Present
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
C1693440795-GES_DISC
Data State
ACTIVE
Number of Files/Granules
2053818
Processing Level
2
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. (2019). Sounder SIPS: AQUA AIRS IR-only Level 2 CLIMCAPS : Atmosphere, cloud and surface geophysical state V2 [Data set]. NASA Goddard Earth Sciences Data and Information Services Center. https://doi.org/10.5067/ILFPVBTDHTDL Date Accessed: 2026-05-06

Documents

Variables

The table below lists the variables contained within a single granule for this dataset. Variables often contain observed or derived geophysical measurements collected from a variety of sources, including remote sensing instruments on satellite and airborne platforms, field campaigns, in situ measurements, and model outputs. The terms variable, parameter, scientific data set, layer, and band have been used across NASA’s Earth science disciplines; however, variable is the designated nomenclature in NASA’s Common Metadata Repository (CMR). Variable metadata attributes such as Name, Description, Units, Data Type, Fill Value, Valid Range, and Scale Factor allow users to efficiently process and analyze the data. The full range of attributes may not be applicable to all variables. Additional information on variable attributes is typically available in the data, user guide, and/or other product documentation.

For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor Offset
sat_sol_zen solar zenith angle at the satellite degree float32 9.9692099683869E+36 N/A N/A N/A
sat_vel satellite ECR velocity at scan_mid_time m s-1 float32 9.9692099683869E+36 N/A N/A N/A
sat_zen satellite zenith angle at the center of the spot degree float32 9.9692099683869E+36 N/A N/A N/A
scan_mid_time TAI93 at middle of earth scene scans seconds since 1993-01-01 00:00 float64 9.9692099683869E+36 N/A N/A N/A
so2_dof The trace of the averaging kernel matrix as a measure of the number of pieces of information about the sulfur dioxide profile provided by the physical retrieval step. 1 float32 9.9692099683869E+36 N/A N/A N/A
solar_beta_angle Beta angle for the spacecraft orbit, determining the percentage of the orbit that the spacecraft is in direct sunlight. degree float32 9.9692099683869E+36 N/A N/A N/A
sol_azi solar azimuth angle at the center of the spot (clockwise from North) degree float32 9.9692099683869E+36 N/A N/A N/A
sol_zen solar zenith angle at the center of the spot degree float32 9.9692099683869E+36 N/A N/A N/A
spatial_lbl list of spatial directions (X, Y, Z) N/A OTHER N/A N/A N/A N/A
spec_hum mass fraction of water vapor in moist air kg / kg float32 9.9692099683869E+36 N/A N/A N/A
spec_hum_err spec_hum error estimate kg / kg float32 9.9692099683869E+36 N/A N/A N/A
spec_hum_qc spec_hum QC flag N/A int8 -127 N/A N/A N/A
spec_hum_sat_ice saturation specific humidity in equilibrium with ice kg / kg float32 9.9692099683869E+36 N/A N/A N/A
spec_hum_sat_ice_err spec_hum_sat_ice error estimate kg / kg float32 9.9692099683869E+36 N/A N/A N/A
spec_hum_sat_ice_qc spec_hum_sat_ice QC flag N/A int8 -127 N/A N/A N/A
spec_hum_sat_liq saturation specific humidity in equilibrium with liquid water kg / kg float32 9.9692099683869E+36 N/A N/A N/A
spec_hum_sat_liq_err spec_hum_sat_liq error estimate kg / kg float32 9.9692099683869E+36 N/A N/A N/A
spec_hum_sat_liq_qc spec_hum_sat_liq QC flag N/A int8 -127 N/A N/A N/A
subsat_lat sub-satellite latitude at scan_mid_time degrees_north float32 9.9692099683869E+36 N/A N/A N/A
subsat_lon sub-satellite longitude at scan_mid_time degrees_east float32 9.9692099683869E+36 N/A N/A N/A
sun_glint_dist Distance from the center of the calculated sun glint spot to the center of the spot. Note that there may not be a glint for cloudy or land cases and in ocean cases the glint can move based on wind conditions. Fill for night observations. m float32 9.9692099683869E+36 N/A N/A N/A
sun_glint_lat sun glint spot latitude at scan_mid_time. Fill for night observations. degrees_north float32 9.9692099683869E+36 N/A N/A N/A
sun_glint_lon sun glint spot longitude at scan_mid_time. Fill for night observations. degrees_east float32 9.9692099683869E+36 N/A N/A N/A
surf_air_temp near-surface air temperature (~2 meters above surface) Kelvin float32 9.9692099683869E+36 N/A N/A N/A
surf_air_temp_err surf_air_temp error estimate Kelvin float32 9.9692099683869E+36 N/A N/A N/A
surf_air_temp_qc surf_air_temp QC flag N/A int8 -127 N/A N/A N/A
surf_alt mean surface altitude wrt earth model over the FOR m float32 9.9692099683869E+36 N/A N/A N/A
surf_alt_sdev standard deviation of surface altitude within the FOR m float32 9.9692099683869E+36 N/A N/A N/A
surf_gp_hgt geopotential height at the surface m float32 9.9692099683869E+36 N/A N/A N/A
surf_gp_hgt_err surf_gp_hgt error estimate m float32 9.9692099683869E+36 N/A N/A N/A
surf_gp_hgt_qc surf_gp_hgt QC flag N/A int8 -127 N/A N/A N/A
surf_ir_emis infrared surface emissivity 1 float32 9.9692099683869E+36 N/A N/A N/A
surf_ir_emis_err surf_ir_emis error estimate 1 float32 9.9692099683869E+36 N/A N/A N/A
surf_ir_emis_qc surf_ir_emis QC flag N/A int8 -127 N/A N/A N/A
surf_ir_refl infrared surface reflectivity 1 float32 9.9692099683869E+36 N/A N/A N/A
surf_ir_refl_qc infrared surface reflectivity QC flag N/A int8 -127 N/A N/A N/A
surf_ir_wnum Surface infrared emissivity frequencies (hinge points) cm-1 float32 9.9692099683869E+36 N/A N/A N/A
surf_ir_wnum_cnt Number of infrared surface emissivity frequencies 1 int16 -32767 N/A N/A N/A
surf_rel_hum relative humidity near the surface over equilibrium phase 1 float32 9.9692099683869E+36 N/A N/A N/A
surf_rel_hum_err surf_rel_hum error estimate 1 float32 9.9692099683869E+36 N/A N/A N/A
surf_rel_hum_qc surf_rel_hum QC flag N/A int8 -127 N/A N/A N/A
surf_spec_hum Near-surface mass fraction of water vapor in moist air kg / kg float32 9.9692099683869E+36 N/A N/A N/A
surf_spec_hum_err surf_spec_hum error estimate kg / kg float32 9.9692099683869E+36 N/A N/A N/A
surf_spec_hum_qc surf_spec_hum QC flag N/A int8 -127 N/A N/A N/A
surf_spec_hum_sat_ice Near-surface saturation specific humidity in equilibrium with ice kg / kg float32 9.9692099683869E+36 N/A N/A N/A
surf_spec_hum_sat_ice_err surf_spec_hum_sat_ice error estimate kg / kg float32 9.9692099683869E+36 N/A N/A N/A
surf_spec_hum_sat_ice_qc surf_spec_hum_sat_ice QC flag N/A int8 -127 N/A N/A N/A
surf_spec_hum_sat_liq Near-surface saturation specific humidity in equilibrium with liquid water kg / kg float32 9.9692099683869E+36 N/A N/A N/A
surf_spec_hum_sat_liq_err surf_spec_hum_sat_liq error estimate kg / kg float32 9.9692099683869E+36 N/A N/A N/A
surf_spec_hum_sat_liq_qc surf_spec_hum_sat_liq QC flag N/A int8 -127 N/A N/A N/A
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