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Description

Atmospheric Infrared Sounder (AIRS) is a grating spectrometer (R = 1200) aboard the second Earth Observing System (EOS) polar-orbiting platform, EOS Aqua. In combination with the Advanced Microwave Sounding Unit (AMSU) and the Humidity Sounder for Brazil (HSB), AIRS constitutes an innovative atmospheric sounding group of visible, infrared, and microwave sensors. This product is the AIRS mid-tropospheric Carbon Dioxide (CO2) Level 3 8-day Gridded Retrieval, from the AIRS and AMSU instruments on board of Aqua satellite. It is 8-day gridded data, at 2.5x2 deg (lon)x(lat) grid cell size. The data is in mole fraction units (data x 10^6 =ppm in volume). This is a total tropospheric column property. The file format is HDF-EOS 2.12 corresponding to HDF4. This AIRS mid-tropospheric CO2 Level 3, 8-day, Gridded Retrieval Product contains standard retrieval means, standard deviations and input counts as well as the latitude and longitude arrays giving the centers of the grid boxes. Each file covers an 8-day period. The mean values are simply the arithmetic means of the individual CO2 retrievals which fall within that grid box over the 8-day period. The mid-tropospheric CO2 retrievals have been averaged and binned into 2.5 x 2 deg grid cells, from -180.0 to +180.0 deg longitude and from -60.0 to +90.0 deg latitude. For each grid map of 4-byte floating-point mean values there is a corresponding 4-byte floating-point map of standard deviation and a 2-byte integer grid map of counts. The counts map provides the user with the number of points per bin that were included in the mean.

Product Summary

Platforms
Aqua
Instruments
AIRS ,
AMSU-A
Spatial Extent

N: 90 S: -60 E: 180 W: -180

Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
2002-09-01 to 2012-02-25
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
C1238517303-GES_DISC
Data State
COMPLETE
Number of Files/Granules
345
Processing Level
3
Published
Updated
Science Keywords
Absorption ,
Radiative Forcing ,
Atmospheric Carbon Dioxide

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

AIRS Science Team, & Texeira, J. (2009). AIRS/Aqua Level 3 8-day CO2 in the free troposphere (AIRS+AMSU), Version 005 [Data set]. NASA Goddard Earth Sciences Data and Information Services Center. https://doi.org/10.5067/AQUA/AIRS/DATA337 Date Accessed: 2025-12-14

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
Latitude Latitude degrees_north float32 -9999 N/A N/A
Longitude Longitude degrees_east float32 -9999 N/A N/A
mole_fraction_of_carbon_dioxide_in_free_troposphere mole_fraction_of_carbon_dioxide_in_free_troposphere N/A float32 -9999 N/A N/A
mole_fraction_of_carbon_dioxide_in_free_troposphere_count mole_fraction_of_carbon_dioxide_in_free_troposphere_count N/A int32 0 N/A N/A
mole_fraction_of_carbon_dioxide_in_free_troposphere_sdev mole_fraction_of_carbon_dioxide_in_free_troposphere_sdev N/A float32 -9999 N/A N/A
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