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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

Geographic Region
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: 2025-12-13

Documents

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_pres_h2o_nsurf Index in air_pres_h2o of the level at the surface. Values at levels beyond this are invalid, representing data below the Earth's surface. 1 int16 -32767 N/A N/A
air_pres_lay pressure at the middle of each layer Pa float32 9.9692099683869E+36 N/A N/A
air_pres_lay_bnds Min and max pressure of each layer Pa float32 9.9692099683869E+36 N/A N/A
air_pres_lay_nsurf Index in air_pres_lay of the layer at the surface. Values for layers beyond this are invalid, representing data below the Earth's surface. 1 int16 -32767 N/A N/A
air_pres_nsurf Index in air_pres of the level at the surface. Values at levels beyond this are invalid, representing data below the Earth's surface. 1 int16 -32767 N/A N/A
air_temp air temperature profile Kelvin float32 9.9692099683869E+36 N/A N/A
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
air_temp_err air_temp error estimate Kelvin float32 9.9692099683869E+36 N/A N/A
air_temp_qc air_temp QC flag N/A int8 -127 N/A N/A
asc_flag ascending orbit flag: 1 if ascending, 0 descending N/A uint8 255 N/A N/A
asc_node_local_solar_time local apparent solar time at the last ascending node before time_coverage_end in hours from midnight hours float32 9.9692099683869E+36 N/A N/A
asc_node_lon Longitude of the last ascending node of spacecraft orbit before time_coverage_end. degrees_east float32 9.9692099683869E+36 N/A N/A
asc_node_tai93 TAI93 time of the last ascending node of spacecraft orbit before time_coverage_end. seconds since 1993-01-01 00:00 float64 9.9692099683869E+36 N/A N/A
attitude_lbl list of rotational directions (roll, pitch, yaw) N/A OTHER N/A N/A N/A
aux/a0_cloud intercept of alpha(1)=f(alpha(2)) fitting 1 float32 9.9692099683869E+36 N/A N/A
aux/aeff_1 A_eff(1st eta step) 1 float32 9.9692099683869E+36 N/A N/A
aux/aeff_end A_eff(last eta step) 1 float32 9.9692099683869E+36 N/A N/A
aux/ampl_eta cloud clearing noise amplification factor 1 float32 9.9692099683869E+36 N/A N/A
aux/bad_mw_ret Flag for bad microwave retrieval from bits 2 and 4 (values 2 and 8) of ispare_2. N/A uint8 255 N/A N/A
aux/bad_phys_ret Flag for bad physical retrieval from bit 1 (value 1) of ispare_2. N/A uint8 255 N/A N/A
aux/bad_reg_ret Flag for bad regression retrieval bits 3 and 5 (values 4 and 16) of ispare_2. N/A uint8 255 N/A N/A
aux/blue_spike_fire Blue spike fire signal strength. Experimental. 1 float32 9.9692099683869E+36 N/A N/A
aux/bt2 RMS(T(p) f/IR.ret - T(p) f/ AMSU.ret) 1 float32 9.9692099683869E+36 N/A N/A
aux/c2h6_dbt Brightness temperature difference near 823 cm-1 indicating ethane. Values over +0.05 K are potential detections. Experimental. Kelvin float32 9.9692099683869E+36 N/A N/A
aux/c3h6_dbt Brightness temperature difference near 911 cm-1 indicating propylene. Values over +0.05 K are potential detections. Experimental. Kelvin float32 9.9692099683869E+36 N/A N/A
aux/c5h8_dbt Brightness temperature difference near 893 cm-1 indicating isoprene. Values over +0.05 K are potential detections. Experimental. Kelvin float32 9.9692099683869E+36 N/A N/A
aux/chi2_ch4 Methane chi^2 of alpha(1)=f(alpha(2)) fitting 1 float32 9.9692099683869E+36 N/A N/A
aux/chi2_co Carbon monoxide chi^2 of alpha(1)=f(alpha(2)) fitting 1 float32 9.9692099683869E+36 N/A N/A
aux/chi2_co2 Carbon dioxide chi^2 of alpha(1)=f(alpha(2)) fitting 1 float32 9.9692099683869E+36 N/A N/A
aux/chi2_h2o Water vapor chi^2 of alpha(1)=f(alpha(2)) fitting 1 float32 9.9692099683869E+36 N/A N/A
aux/chi2_hno3 Nitric acid chi^2 of alpha(1)=f(alpha(2)) fitting 1 float32 9.9692099683869E+36 N/A N/A
aux/chi2_n2o Nitrous oxide chi^2 of alpha(1)=f(alpha(2)) fitting 1 float32 9.9692099683869E+36 N/A N/A
aux/chi2_o3 Ozone chi^2 of alpha(1)=f(alpha(2)) fitting 1 float32 9.9692099683869E+36 N/A N/A
aux/chi2_so2 Sulfur dioxide chi^2 of alpha(1)=f(alpha(2)) fitting 1 float32 9.9692099683869E+36 N/A N/A
aux/chi2_temp Temperature profile chi^2 of alpha(1)=f(alpha(2)) fitting 1 float32 9.9692099683869E+36 N/A N/A
aux/cldfrc_500 Total cloud fraction over FOR below 500 hPa 1 float32 9.9692099683869E+36 N/A N/A
aux/cldfrc_tot Total cloud fraction over FOR 1 float32 9.9692099683869E+36 N/A N/A
aux/clim_co2_mmr Assumed carbon dioxide concentration 1 float32 9.9692099683869E+36 N/A N/A
aux/clim_surf_ir_emis Infrared surface emissivity from the climatology first guess 1 float32 9.9692099683869E+36 N/A N/A
aux/clim_surf_ir_refl infrared surface reflectivity from the climatology first guess 1 float32 9.9692099683869E+36 N/A N/A
aux/clim_surf_ir_wnum Surface infrared emissivity frequencies (hinge points) for the climatology first guess cm-1 float32 9.9692099683869E+36 N/A N/A
aux/clim_surf_ir_wnum_cnt Number of infrared surface emissivity frequencies for the climatology first guess 1 int16 -32767 N/A N/A
aux/co2_vmr carbon dioxide volume mixing ratio 1 float32 9.9692099683869E+36 N/A N/A
aux/co2_vmr_err co2_vmr error estimate 1 float32 9.9692099683869E+36 N/A N/A
aux/co2_vmr_qc co2_vmr QC flag N/A int8 -127 N/A N/A
aux/etarej cloud clearing residual used f/ rej at iteration = ieta_rej 1 float32 9.9692099683869E+36 N/A N/A
aux/fg_air_temp air temperature profile from the MERRA2 first guess Kelvin float32 9.9692099683869E+36 N/A N/A
aux/fg_h2o_vap_mol_lay water vapor layer totals from the MERRA2 first guess molecules / m2 float32 9.9692099683869E+36 N/A N/A
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