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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 Normal Spectral Resolution (NSR) data. The CrIS instrument is a Fourier transform spectrometer with a total of 1305 NSR infrared sounding channels covering the longwave (655-1095 cm-1), midwave (1210-1750 cm-1), and shortwave (2155-2550 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. 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.

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.

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
2012-01-20 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
C1692982070-GES_DISC
Data State
ACTIVE
Number of Files/Granules
780070
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

Sounder SIPS, & Barnet, C. (2020). Sounder SIPS: Suomi NPP CrIMSS Level 2 CLIMCAPS Normal Spectral Resolution: Atmosphere cloud and surface geophysical state V2 [Data set]. NASA Goddard Earth Sciences Data and Information Services Center. https://doi.org/10.5067/9HR0XHCH3IGS 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
aux/fg_o3_mol_lay Ozone layer total from the MERRA2 first guess molecules / m2 float32 9.9692099683869E+36 N/A N/A N/A
aux/fg_surf_air_temp near-surface air temperature (~2 meters above surface) from the MERRA2 first guess Kelvin float32 9.9692099683869E+36 N/A N/A N/A
aux/fg_surf_temp radiative temperature of the surface from the MERRA2 first guess Kelvin float32 9.9692099683869E+36 N/A N/A N/A
aux/for_cld_frac_2lay Effective cloud fraction assuming 2 common cloud layers over the whole Field-Of-Regard 1 float32 9.9692099683869E+36 N/A N/A N/A
aux/for_cld_frac_2lay_err for_cld_frac_2lay error estimate 1 float32 9.9692099683869E+36 N/A N/A N/A
aux/for_cld_frac_2lay_qc for_cld_frac_2lay QC flag N/A int8 -127 N/A N/A N/A
aux/for_cld_frac_tot Field-Of-Regard effective cloud fraction summed over all cloud layers 1 float32 9.9692099683869E+36 N/A N/A N/A
aux/for_cld_frac_tot_err for_cld_frac_tot error estimate 1 float32 9.9692099683869E+36 N/A N/A N/A
aux/for_cld_frac_tot_qc for_cld_frac_tot QC flag N/A int8 -127 N/A N/A N/A
aux/for_cld_top_pres_2lay Cloud top pressure assuming 2 common cloud layers over the whole Field-of-Regard Pa float32 9.9692099683869E+36 N/A N/A N/A
aux/for_cld_top_pres_2lay_err for_cld_top_pres_2lay error estimate 1 float32 9.9692099683869E+36 N/A N/A N/A
aux/for_cld_top_pres_2lay_qc for_cld_top_pres_2lay QC flag N/A int8 -127 N/A N/A N/A
aux/for_cld_top_pres_tot Field-Of-Regard weighted cloud top pressure Pa float32 9.9692099683869E+36 N/A N/A N/A
aux/for_cld_top_pres_tot_err for_cld_top_pres_tot error estimate 1 float32 9.9692099683869E+36 N/A N/A N/A
aux/for_cld_top_pres_tot_qc for_cld_top_pres_tot QC flag N/A int8 -127 N/A N/A N/A
aux/fov_weight Contribution weighting of FOV within FOR for cloud cleared radiances. Can be negative. 1 float32 9.9692099683869E+36 N/A N/A N/A
aux/idprof profile ID N/A OTHER N/A N/A N/A N/A
aux/ir_x RMS(rad(IR.ret)-radobs()) for AMSU channels 1 float32 9.9692099683869E+36 N/A N/A N/A
aux/ispare_2 Bit flags for rejection of retrieval steps. Details are algorithm-specific. N/A uint16 65535 N/A N/A N/A
aux/nbest level index of highest pressure (i.e. lowest altitude) for which Quality = 0. A value of 0 indicates that no part of the profile passes the test. 1 int16 -32767 N/A N/A N/A
aux/ngood level index of highest pressure (i.e. lowest altitude) for which Quality = 0 or 1. A value of 0 indicates that no part of the profile passes the test. 1 int16 -32767 N/A N/A N/A
aux/nh3_dbt Brightness temperature difference sum indicating ammonia. Sum of lines near 929 and 966 cm-1. Values over +1.0 K are potential detections. Experimental. Kelvin float32 9.9692099683869E+36 N/A N/A N/A
aux/pbest Maximum value of pressure for which temperature is Quality = 0 Pa float32 9.9692099683869E+36 N/A N/A N/A
aux/pgood Maximum value of pressure for which temperature is Quality = 0 or 1 Pa float32 9.9692099683869E+36 N/A N/A N/A
aux/prior_sea_lev_pres sea level surface pressure from forecast Pa float32 9.9692099683869E+36 N/A N/A N/A
aux/prior_surf_pres surface pressure from forecast Pa float32 9.9692099683869E+36 N/A N/A N/A
aux/qualsurf qualsurf N/A float32 9.9692099683869E+36 N/A N/A N/A
aux/qualtemp qualtemp N/A float32 9.9692099683869E+36 N/A N/A N/A
aux/softcode software rejection code N/A float32 9.9692099683869E+36 N/A N/A N/A
aux/surf_dew_point_temp Near-surface dew-point temperature Kelvin float32 9.9692099683869E+36 N/A N/A N/A
aux/surf_dew_point_temp_qc surf_dew_point_temp QC flag N/A int8 -127 N/A N/A N/A
aux/surf_h2o_vap_pres_deficit Near-surface water vapor saturation pressure deficit Pa float32 9.9692099683869E+36 N/A N/A N/A
aux/surf_h2o_vap_pres_deficit_qc surf_h2o_vap_pres_deficit QC flag N/A int8 -127 N/A N/A N/A
aux/totliqwat total liquid water (MW) 1 float32 9.9692099683869E+36 N/A N/A N/A
ave_kern/air_temp_ave_kern Averaging kernel for air temperature retrieval 1.0f float32 9.9692099683869E+36 N/A N/A N/A
ave_kern/air_temp_func_hbot Flag if the bottom air_temperature trapezoidal basis function has value of 1/2 or 1 at 110000 Pa. N/A int16 -32767 N/A N/A N/A
ave_kern/air_temp_func_htop Flag if the top air_temperature trapezoidal basis function has value of 1/2 or 1 at TOA. N/A int16 -32767 N/A N/A N/A
ave_kern/air_temp_func_indxs Pressure indexes defining the trapezoidal basis functions for the air temperature profile 1s int16 -32767 N/A N/A N/A
ave_kern/air_temp_func_last_indx Last valid index for all quantities with dimension air_temp_func_pres for a given profile. Any further basis functions would be cut off by the surface. Zero when the entire ave_kern matrix is invalid. 1s int16 -32767 N/A N/A N/A
ave_kern/air_temp_func_pres Static mean pressures for each vertical basis function used to represent the air temperature profile. Pa float32 9.9692099683869E+36 N/A N/A N/A
ave_kern/ch4_ave_kern Averaging kernel for methane retrieval 1.0f float32 9.9692099683869E+36 N/A N/A N/A
ave_kern/ch4_func_hbot Flag if the bottom methane trapezoidal basis function has value of 1/2 or 1 at 110000 Pa. N/A int16 -32767 N/A N/A N/A
ave_kern/ch4_func_htop Flag if the top methane trapezoidal basis function has value of 1/2 or 1 at TOA. N/A int16 -32767 N/A N/A N/A
ave_kern/ch4_func_indxs Pressure indexes defining the trapezoidal basis functions for the methane profile 1s int16 -32767 N/A N/A N/A
ave_kern/ch4_func_last_indx Last valid index for all quantities with dimension ch4_func_pres for a given profile. Any further basis functions would be cut off by the surface. Zero when the entire ave_kern matrix is invalid. 1s int16 -32767 N/A N/A N/A
ave_kern/ch4_func_pres Static mean pressures for each vertical basis function used to represent the methane profile. Pa float32 9.9692099683869E+36 N/A N/A N/A
ave_kern/co2_ave_kern Averaging kernel for carbon dioxide retrieval 1.0f float32 9.9692099683869E+36 N/A N/A N/A
ave_kern/co2_func_hbot Flag if the bottom carbon dioxide trapezoidal basis function has value of 1/2 or 1 at 110000 Pa. N/A int16 -32767 N/A N/A N/A
ave_kern/co2_func_htop Flag if the top carbon dioxide trapezoidal basis function has value of 1/2 or 1 at TOA. N/A int16 -32767 N/A N/A N/A
ave_kern/co2_func_indxs Pressure indexes defining the trapezoidal basis functions for the carbon dioxide profile 1s int16 -32767 N/A N/A N/A
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