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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 Cross-track Infrared Sounder/Advanced Technology Microwave Sounder (CrIS/ATMS) instruments, also known as CrIMSS (Cross-track Infrared and Microwave Sounding Suite). The CrIS/ATMS instruments used for this product are on board the Suomi National Polar-orbiting Partnership (SNPP) platform and use the Full Spectral Resolution (FSR) data. The CrIS instrument is a Fourier transform spectrometer with a total of 2211 FSR infrared sounding channels covering the longwave (645-1095 cm-1), midwave (1210-1750 cm-1), and shortwave (2000-2550 cm-1) spectral regions. The ATMS instrument is a cross-track scanner with 22 channels in spectral bands from 23 GHz through 183 GHz.

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.

A 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.

The CLIMCAPS algorithm uses data from the second Modern-Era Retrospective analysis for Research and Applications (MERRA-2) as a first-guess for the atmospheric state. Because MERRA-2 products typically have a latency from 3 to 7 weeks, so too do the CLIMCAPS products.

Product Summary

Platforms
Suomi-NPP
Instruments
CrIS ,
ATMS
Spatial Extent

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

Location
GLOBAL
Coordinate System
GEODETIC
Granule Spatial Representation
GEODETIC
Temporal Extent
2015-11-02 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
C1692982075-GES_DISC
Data State
ACTIVE
Number of Files/Granules
459480
Processing Level
2
Published
Updated
Science Keywords
Tropospheric Ozone ,
Tropopause ,
Atmospheric Chemistry ,
Carbon And Hydrocarbon Compounds ,
Methane ,
Outgoing Longwave Radiation ,
Atmospheric Temperature ,
Surface Temperature ,
Air Temperature ,
Skin Temperature ,
Upper Air Temperature ,
Vertical Profiles ,
Atmospheric Water Vapor ,
Layered Precipitable Water ,
Total Precipitable Water ,
Cloud Properties ,
Cloud Fraction ,
Cloud Top Temperature ,
Precipitation ,
Skin Temperature ,
Ocean Temperature ,
Sea Surface Skin 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

Sounder SIPS, & Barnet, C. (2020). Sounder SIPS: Suomi NPP CrIMSS Level 2 CLIMCAPS Full Spectral Resolution: Atmosphere cloud and surface geophysical state V2 [Data set]. NASA Goddard Earth Sciences Data and Information Services Center. https://doi.org/10.5067/62SPJFQW5Q9B Date Accessed: 2026-05-14

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
mw/mw_air_temp air temperature profile from the MW-only step Kelvin float32 9.9692099683869E+36 N/A N/A N/A
mw/mw_air_temp_err mw_air_temp error estimate Kelvin float32 9.9692099683869E+36 N/A N/A N/A
mw/mw_air_temp_qc mw_air_temp QC flag N/A int8 -127 N/A N/A N/A
mw/mw_h2o_vap_mol_lay Water vapor layer total from the MW-only step molecules / m2 float32 9.9692099683869E+36 N/A N/A N/A
mw/mw_h2o_vap_mol_lay_qc mw_h2o_vap_mol_lay QC flag N/A int8 -127 N/A N/A N/A
mw/mw_h2o_vap_tot Total precipitable water vapor from the MW-only step kg / m2 float32 9.9692099683869E+36 N/A N/A N/A
mw/mw_h2o_vap_tot_err mw_h2o_vap_tot error estimate kg / m2 float32 9.9692099683869E+36 N/A N/A N/A
mw/mw_h2o_vap_tot_qc mw_h2o_vap_tot QC flag N/A int8 -127 N/A N/A N/A
mw/mw_spec_hum mass fraction of water vapor in moist air from the MW-Only step 1 float32 9.9692099683869E+36 N/A N/A N/A
mw/mw_spec_hum_err mw_spec_hum error estimate 1 float32 9.9692099683869E+36 N/A N/A N/A
mw/mw_spec_hum_qc mw_spec_hum QC flag N/A int8 -127 N/A N/A N/A
mw/mw_surf_air_temp Near-surface air temperature (~2 meters above surface) from the MW-only step Kelvin float32 9.9692099683869E+36 N/A N/A N/A
mw/mw_surf_air_temp_err mw_surf_air_temp error estimate Kelvin float32 9.9692099683869E+36 N/A N/A N/A
mw/mw_surf_air_temp_qc mw_surf_air_temp QC flag N/A int8 -127 N/A N/A N/A
mw/mw_surf_mw_emis Microwave surface emissivity from the MW-only retrieval step 1 float32 9.9692099683869E+36 N/A N/A N/A
mw/mw_surf_mw_emis_err mw_surf_mw_emis error estimate 1 float32 9.9692099683869E+36 N/A N/A N/A
mw/mw_surf_mw_emis_qc mw_surf_mw_emis QC flag N/A int8 -127 N/A N/A N/A
mw/mw_surf_spec_hum Near-surface mass fraction of water vapor in moist air from the MW-Only step 1 float32 9.9692099683869E+36 N/A N/A N/A
mw/mw_surf_spec_hum_err mw_surf_spec_hum error estimate 1 float32 9.9692099683869E+36 N/A N/A N/A
mw/mw_surf_spec_hum_qc mw_surf_spec_hum QC flag N/A int8 -127 N/A N/A N/A
mw/mw_surf_temp Radiative temperature of the surface from the MW-only step Kelvin float32 9.9692099683869E+36 N/A N/A N/A
mw/mw_surf_temp_err mw_surf_temp error estimate Kelvin float32 9.9692099683869E+36 N/A N/A N/A
mw/mw_surf_temp_qc mw_surf_temp QC flag N/A int8 -127 N/A N/A N/A
mw_cld_phase Cloud Ice/Water flag from microwave. 0 for liquid clouds or no clouds; 1 for ice clouds. N/A int16 -32767 N/A N/A N/A
mw_surf_class Microwave spectral surface class. 0 for coastline; 1 for land; 2 for ocean; 3 for first-year sea-ice; 4 for multi-year sea-ice; 5 for snow (higher-freq scattering); 6 for glacier/snow (very low-freq scattering); 7 for snow (lower-freq scattering); N/A int16 -32767 N/A N/A N/A
n2o_dof The trace of the averaging kernel matrix as a measure of the number of pieces of information about the nitrous oxide profile provided by the physical retrieval step. 1 float32 9.9692099683869E+36 N/A N/A N/A
num_cld Number of cloud layers with nonzero cloud fraction 1 int8 -127 N/A N/A N/A
num_cld_qc QC flag for number of cloud layers N/A int8 -127 N/A N/A N/A
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 N/A
o3_mmr ozone mass mixing ratio to dry air 1 float32 9.9692099683869E+36 N/A N/A N/A
o3_mmr_err o3_mmr error estimate 1 float32 9.9692099683869E+36 N/A N/A N/A
o3_mmr_qc o3_mmr QC flag N/A int8 -127 N/A N/A N/A
o3_tot Total column ozone. (Multiply by 4.670e5 to convert to Dobson Units from kg m^-2) kg m-2 float32 9.9692099683869E+36 N/A N/A N/A
o3_tot_err o3_tot error estimate kg m-2 float32 9.9692099683869E+36 N/A N/A N/A
o3_tot_qc o3_tot QC flag N/A int8 -127 N/A N/A N/A
obs_id unique earth view observation identifier: yyyymmddThhmm.aaExx. Includes gran_id plus 2-digit along-track index (01-45) and 2-digit cross-track index (01-30). N/A OTHER N/A N/A N/A N/A
obs_time_tai93 earth view observation midtime for each FOV seconds since 1993-01-01 00:00 float64 9.9692099683869E+36 N/A N/A N/A
obs_time_utc UTC earth view observation time as an array of integers: year, month, day, hour, minute, second, millisec, microsec N/A uint16 65535 N/A N/A N/A
rel_hum relative humidity over equilibrium phase 1 float32 9.9692099683869E+36 N/A N/A N/A
rel_hum_err rel_hum error estimate 1 float32 9.9692099683869E+36 N/A N/A N/A
rel_hum_qc rel_hum QC flag N/A int8 -127 N/A N/A N/A
sat_alt satellite altitude with respect to earth model at scan_mid_time m float32 9.9692099683869E+36 N/A N/A N/A
sat_att satellite attitude at scan_mid_time. An orthogonal triad. First element is angle about the +x (roll) ORB axis. +x axis is positively oriented in the direction of orbital flight. Second element is angle about +y (pitch) ORB axis. +y axis is oriented normal to the orbit plane with the positive sense opposite to that of the orbit's angular momentum vector H. Third element is angle about +z (yaw) axis. +z axis is positively oriented Earthward parallel to the satellite radius vector R from the spacecraft center of mass to the center of the Earth. degree float32 9.9692099683869E+36 N/A N/A N/A
sat_azi satellite azimuth angle at the center of the spot (clockwise from North) degree float32 9.9692099683869E+36 N/A N/A N/A
sat_pos satellite ECR position at scan_mid_time m float32 9.9692099683869E+36 N/A N/A N/A
sat_range line of sight distance between satellite and spot center m float32 9.9692099683869E+36 N/A N/A N/A
sat_sol_azi solar azimuth angle at the satellite (clockwise from North) degree float32 9.9692099683869E+36 N/A N/A N/A
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
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