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Description

This level 2 support product is generated by the SiFSAP (Single Field-of-View Sounder Atmospheric Products) algorithm. The SIFSAP algorithm provides retrieval for each sounder Field of View (FOV), therefore, it has 3-times higher horizontal spatial resolution and 9-time denser products compared to other current IR sounder products. Since SiFSAP is an FOV-based algorithm, its product variables have an additional dimension which represents the number of FOVs. For CrIS instrument, there are 9 FOVs for each Field of Regard (FOR). The SiFSAP Level-2 retrieval products contain a variety of geophysical parameters retrieved from IR/MW sounder suites measurements, including profiles of temperature, water vapor and trace gas species as well as clouds and surface properties. This support product provides height vertical sampling (up to 98 levels) and also includes more detailed Empirical Orthogonal Function (EOF) information like averaging kernels. A level 2 granule has been set as 6 minutes of data. There are 240 granules per day, with an orbit repeat cycle of approximately 16 day.

Product Summary

Platforms
Suomi-NPP
Instruments
ATMS ,
CrIS
Spatial Extent

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

Location
GLOBAL
Coordinate System
GEODETIC
Granule Spatial Representation
GEODETIC
Temporal Extent
2015-11-02
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
C2782339991-GES_DISC
Data State
ACTIVE
Number of Files/Granules
460114
Processing Level
2
Published
Updated
Science Keywords
Surface Pressure ,
Surface Temperature ,
Air Temperature ,
Upper Air Temperature ,
Layered Precipitable Water ,
Total Precipitable Water ,
Water Vapor Profiles ,
Skin Temperature ,
Sea Surface Temperature ,
Liquid Water Equivalent ,
Relative Humidity ,
Specific Humidity ,
Atmospheric Ozone ,
Total Ozone ,
Atmospheric Carbon Monoxide ,
Methane ,
Cloud Optical Depth/Thickness ,
Temperature Gradient Rate

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

Liu, X. (2022). Sounder SIPS: Suomi NPP CrIMSS Level 2 SiFSAP Support: Atmosphere cloud and surface geophysical state per footprint V2 [Data set]. NASA Goddard Earth Sciences Data and Information Services Center. https://doi.org/10.5067/XQMJMVTQSGIS Date Accessed: 2026-05-16

Documents

READ-ME

ALGORITHM THEORETICAL BASIS DOCUMENT (ATBD)

SCIENCE DATA PRODUCT VALIDATION

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
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 FOV m float32 9.9692099683869E+36 N/A N/A N/A
surf_alt_sdev standard deviation of surface altitude within the FOV m float32 9.9692099683869E+36 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_dof The trace of the averaging kernel matrix as a measure of the amount of information about the surface IR emissivity extracted from the measured radiation. 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_mw_emis Microwave surface emissivity 1 float32 9.9692099683869E+36 N/A N/A N/A
surf_mw_emis_dof The trace of the averaging kernel matrix as a measure of the amount of information about the surface MW emissivity extracted from the measured radiation. 1 float32 9.9692099683869E+36 N/A N/A N/A
surf_mw_emis_err surf_mw_emis error estimate 1 float32 9.9692099683869E+36 N/A N/A N/A
surf_mw_emis_qc surf_mw_emis QC flag N/A int8 -127 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_temp radiative temperature of the surface kelvin float32 9.9692099683869E+36 N/A N/A N/A
surf_temp_dof The trace of the averaging kernel matrix as a measure of the amount of information about the surface temperature extracted from the measured radiation. 1 float32 9.9692099683869E+36 N/A N/A N/A
surf_temp_err surf_temp error estimate kelvin float32 9.9692099683869E+36 N/A N/A N/A
surf_temp_qc surf_temp QC flag N/A int8 -127 N/A N/A N/A
surf_wnum_ir Surface infrared emissivity frequencies (hinge points) cm-1 float32 9.9692099683869E+36 N/A N/A N/A
tpause_gp_hgt Derived tropopause geopotential height, where tropopause is determined according to the WMO definition m float32 9.9692099683869E+36 N/A N/A N/A
tpause_gp_hgt_qc tpause_gp_hgt QC flag N/A int8 -127 N/A N/A N/A
tpause_pres Derived tropopause pressure, where tropopause is determined according to the WMO definition Pa float32 9.9692099683869E+36 N/A N/A N/A
tpause_pres_qc tpause_pres QC flag N/A int8 -127 N/A N/A N/A
tpause_temp Derived tropopause temperature, where tropopause is determined according to the WMO definition kelvin float32 9.9692099683869E+36 N/A N/A N/A
tpause_temp_qc tpause_temp QC flag N/A int8 -127 N/A N/A N/A
utc_tuple_lbl names of the elements of UTC when it is expressed as an array of integers year,month,day,hour,minute,second,millisecond,microsecond N/A OTHER N/A N/A N/A N/A
view_ang off nadir pointing angle degree float32 9.9692099683869E+36 N/A N/A N/A
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