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Description

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
C2790892760-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: Nadia Smith. (2024). Sounder SIPS: Suomi NPP CrIMSS Level 2 CLIMCAPS Full Spectral Resolution: retrieved atmospheric state V2.1 [Data set]. NASA Goddard Earth Sciences Data and Information Services Center. https://doi.org/10.5067/SD6WORV4GX8P 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
ave_kern/co_func_last_indx Last valid index for all quantities with dimension co_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/co_func_pres Static mean pressures for each vertical basis function used to represent the carbon monoxide profile. Pa float32 9.9692099683869E+36 N/A N/A N/A
ave_kern/h2o_vap_ave_kern Averaging kernel for water vapor retrieval 1.0f float32 9.9692099683869E+36 N/A N/A N/A
ave_kern/h2o_vap_func_hbot Flag if the bottom water_vapor 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/h2o_vap_func_htop Flag if the top water vapor trapezoidal basis function has value of 1/2 or 1 at TOA. N/A int16 -32767 N/A N/A N/A
ave_kern/h2o_vap_func_indxs Pressure indexes defining the trapezoidal basis functions for the water vapor profile 1s int16 -32767 N/A N/A N/A
ave_kern/h2o_vap_func_last_indx Last valid index for all quantities with dimension h2o_vap_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/h2o_vap_func_pres Static mean pressures for each vertical basis function used to represent the water vapor profile. Pa float32 9.9692099683869E+36 N/A N/A N/A
ave_kern/hno3_ave_kern Averaging kernel for nitric acid retrieval 1.0f float32 9.9692099683869E+36 N/A N/A N/A
ave_kern/hno3_func_hbot Flag if the bottom nitric acid 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/hno3_func_htop Flag if the top nitric acid trapezoidal basis function has value of 1/2 or 1 at TOA. N/A int16 -32767 N/A N/A N/A
ave_kern/hno3_func_indxs Pressure indexes defining the trapezoidal basis functions for the nitric acid profile 1s int16 -32767 N/A N/A N/A
ave_kern/hno3_func_last_indx Last valid index for all quantities with dimension hno3_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/hno3_func_pres Static mean pressures for each vertical basis function used to represent the nitric acid profile. Pa float32 9.9692099683869E+36 N/A N/A N/A
ave_kern/o3_ave_kern Averaging kernel for ozone retrieval 1.0f float32 9.9692099683869E+36 N/A N/A N/A
ave_kern/o3_func_hbot Flag if the bottom ozone 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/o3_func_htop Flag if the top ozone trapezoidal basis function has value of 1/2 or 1 at TOA. N/A int16 -32767 N/A N/A N/A
ave_kern/o3_func_indxs Pressure indexes defining the trapezoidal basis functions for the ozone profile 1s int16 -32767 N/A N/A N/A
ave_kern/o3_func_last_indx Last valid index for all quantities with dimension o3_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/o3_func_pres Static mean pressures for each vertical basis function used to represent the ozone profile. Pa float32 9.9692099683869E+36 N/A N/A N/A
ch4_mol_lay CLIMCAPS retrieved methane layer total on pressure layers (air_pres_lay). The value for the lowest layer is prorated to represent the number of molecules between the fixed top of that layer listed in air_pres_lay_bnds and the local surface pressure (prior_surf_pres). molecules / m2 float32 9.9692099683869E+36 N/A N/A N/A
ch4_mol_lay_err ch4_mol_lay error estimate molecules / m2 float32 9.9692099683869E+36 N/A N/A N/A
cld_frac effective cloud fraction 1 float32 9.9692099683869E+36 N/A N/A N/A
cld_frac_err effective cloud fraction error estimate 1 float32 9.9692099683869E+36 N/A N/A N/A
cld_frac_for Derived effective cloud fraction for up to two layers of clouds over the whole Field-Of-Regard 1 float32 9.9692099683869E+36 N/A N/A N/A
cld_lay_lbl Cloud layer {top, bottom} N/A OTHER N/A N/A N/A N/A
cld_top_pres_for Cloud top pressure for up to two cloud layers over the whole Field-of-Regard Pa float32 9.9692099683869E+36 N/A N/A N/A
co2_vmr_midtrop Average column mixing ratio of co2_vmr in mid-troposphere, 200-500 hPa. Multiply by 1.0e06 to convert to ppm See co2_vmr_err for error estimate. m3 / m3 float32 9.9692099683869E+36 N/A N/A N/A
co_mol_lay CLIMCAPS retrieved carbon monoxide layer total on pressure layers (air_pres_lay). The value for the lowest layer is prorated to represent the number of molecules between the fixed top of that layer listed in air_pres_lay_bnds and the local surface pressure (prior_surf_pres). molecules / m2 float32 9.9692099683869E+36 N/A N/A N/A
co_mol_lay_err co_mol_lay error estimate molecules / m2 float32 9.9692099683869E+36 N/A N/A N/A
fov_land_frac land fraction over the FOV 1 float32 9.9692099683869E+36 N/A N/A N/A
fov_lat latitude of FOV center degrees_north float32 9.9692099683869E+36 N/A N/A N/A
fov_lat_bnds latitudes of points forming a polygon around the perimeter of the FOV degrees_north float32 9.9692099683869E+36 N/A N/A N/A
fov_lon longitude of FOV center degrees_east float32 9.9692099683869E+36 N/A N/A N/A
fov_lon_bnds longitudes of points forming a polygon around the perimeter of the FOV degrees_east float32 9.9692099683869E+36 N/A N/A N/A
fov_obs_id unique earth view observation identifier for FOV: yyyymmddThhmm.aaExx.f . Includes gran_id plus 2-digit along-track index (01-45), 2-digit cross-track index (01-30), and 1-digit FOV number (1-9). N/A OTHER N/A N/A N/A N/A
fov_surf_alt mean surface altitude wrt earth model over the FOV m float32 9.9692099683869E+36 N/A N/A N/A
fov_surf_alt_sdev standard deviation of surface altitude within the FOV m float32 9.9692099683869E+36 N/A N/A N/A
h2o_vap_mol_lay CLIMCAPS retrieved water vapor layer total on pressure layers (air_pres_lay). The value for the lowest layer is prorated to represent the number of molecules between the fixed top of that layer listed in air_pres_lay_bnds and the local surface pressure (prior_surf_pres). molecules / m2 float32 9.9692099683869E+36 N/A N/A N/A
h2o_vap_mol_lay_err h2o_vap_mol_lay error estimate molecules / m2 float32 9.9692099683869E+36 N/A N/A N/A
hno3_mol_lay CLIMCAPS retrieved nitric acid layer total on pressure layers (air_pres_lay). The value for the lowest layer is prorated to represent the number of molecules between the fixed top of that layer listed in air_pres_lay_bnds and the local surface pressure (prior_surf_pres). molecules / m2 float32 9.9692099683869E+36 N/A N/A N/A
hno3_mol_lay_err hno3_mol_lay error estimate molecules / m2 float32 9.9692099683869E+36 N/A N/A N/A
land_frac land fraction over the FOR 1 float32 9.9692099683869E+36 N/A N/A N/A
lat latitude of FOR center degrees_north float32 9.9692099683869E+36 N/A N/A N/A
lat_bnds latitudes of points forming a polygon around the perimeter of the FOV degrees_north float32 9.9692099683869E+36 N/A N/A N/A
lat_geoid latitude of FOR center on the geoid (without terrain correction) degrees_north float32 9.9692099683869E+36 N/A N/A N/A
lay_air_pres Effective pressure of retrieval layers derived from air_pres and adjusted for surface pressure at target scene Pa float32 9.9692099683869E+36 N/A N/A N/A
local_solar_time local apparent solar time in hours from midnight hours float32 9.9692099683869E+36 N/A N/A N/A
lon longitude of FOR center degrees_east float32 9.9692099683869E+36 N/A N/A N/A
lon_bnds longitudes of points forming a polygon around the perimeter of the FOV degrees_east float32 9.9692099683869E+36 N/A N/A N/A
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