Liguang Wu, Jianchun Qin, A.K.Sharma, Sunmi Cho* and Carrie Phelps

Goddard Earth Sciences DISC DAACNASA Goddard Space Flight Center, Code 902

Greenbelt, Maryland 20771

FACTS ABOUT AIRSSize: stowed: 116.5 x 80 x 95.3 cm

deployed: 116.5 x 158.7 x 95.3 cmMass: 177 kgPower: 220 WData Rate: 1.27 MbpsSpectral Range: IR: 3.74 - 15.4 µm

Vis/NIR: 0.4 - 1.0 µmChannels: IR: 2378

Vis/NIR: 4Aperture: 10 cmInstrument Field of View: IR: 1.1° (= 13.5 km @ nadir)

Vis/NIR: 0.2° (= 2.3 km @ nadir)Swath Width: 99° (= 1650 km)Scan Sampling: IR: 90 x 1.1°Pointing Accuracy: IR: 0.1°Prime Contractor: British Aerospace Systems

(formerly Lockheed-Martin)Responsible Organization: Jet Propulsion Laboratory

AIRS DATA PRODUCTSLevel 1A Geo-located science data counts

Engineering parametersLevel 1B Calibrated geo-located radiance

Brightness temperatureCalibration coefficients

Level 2 Flux Products Clear-column radiance

Outgoing longwave radiation at the top of the

atmosphereOutgoing shortwave radiation

at the top of the atmosphere

Net longwave flux at the surface

Net shortwave flux at the surfaceAtmospheric Temperature Temperature profile (30 levels)Products Troposphere height

Stratosphere heightHumidity Products Water vapor profile

Total precipitable waterCloud liquid-water contentPrecipitation indicationCloud-ice indication

Cloud Products Cloud-top pressureCloud-top temperatureFractional cloud coverCloud optical propertiesCloud type

Ozone Products Ozone profileTotal ozone

Trace Constituent Products MethaneCarbon monoxide

Surface Analysis Products Sea surface skin temperature

Land surface skin temperature

Infrared surface emissivityMicrowave surface emissivity

The Atmospheric Infrared Sounder (AIRS) is selected by NASA to fly aboard the second Earth Observing System (EOS) polar orbiting platform, EOS Aqua, which will be launched in 2002. AIRS, together with the Advanced Microwave Sounding Unit (AMSU) and the Humidity Sounder for Brazil (HSB), is designed to meet the requirements of the NASA Earth Science Enterprise climate research program and NOAA operational weather forecasting

plans. AIRS constitutes an innovative atmospheric sounding group of visible, infrared, and microwave sensors that will provide measurements for temperature at an accuracy of 1 °C in layers 1 km thick and humidity at an accuracy of 20% in layers 2 km in the troposphere.

Data ProductsBesides Level-1 radiance data, the new data set will contain AIRS Level-2 products consisting of 26 parameters. The table to the right lists the AIRS data products. AIRS data will be generated continuously. Global coverage will be obtained twice daily (day and night) on a 1:30 p.m. sun synchronous orbit from a 705-km altitude. For processing convenience, the data along the orbit will be divided into 6-minute scenes. Each orbit has approximately 16 scenes since each orbit takes 98.8 minutes.

All of the data products will be released for public distribution in HDF-EOS format at the NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) Distributed Active Archive Center (DAAC). The Goddard DAAC’s Atmospheric Dynamics Data Support Team will provide science and data support to assist others in understanding, accessing and using the AIRS data products. For questions or comments, please contact atmdyn-dst@daac.gsfc.nasa.gov or visit our AIRS website at:

http://daac.gsfc.nasa.gov/atmodyn/airs/

Data Assistance

Data Services

FACTS ABOUT AMSUInstrument: AMSU-A1 AMSU-A2Size: 72 x 34 x 59 cm 73 x 61 x 86 cmMass: 49 kg 42 kgPower: 77 W 24 WData Rate: 1.5 kbps 0.5 kbpsSpectral Range: 50 - 90 GHz 23 - 32 GHzChannels: 13 2Aperture: 15 cm (two) 30 cm (one)Instrument Field of View: 3.3° (= 40.5 km @ nadir) 3.3° (= 40.5 km @ nadir)Swath Width: 100° (= 1690 km) 100° (= 1690 km)Scan Sampling: 30 x 3.33° 30 x 3.33 °Pointing Accuracy: 0.2° 0.2°Prime Contractor: Aerojet AerojetResponsible Organization:NASA/GSFC NASA/GSFC

FACTS ABOUT HSBSize: 70 x 65 x 46 cmMass: 51 kgPower: 56 WData Rate: 4.2 kbpsSpectral Range: 150 - 190 GHzChannels: 4Aperture: 18.75 cm (one)Instrument Field of View: 1.1° (= 13.5 km @ nadir)Swath Width: 99° (= 1650 km)Scan Sampling: 90 x 1.1°Pointing Accuracy: 0.1°Prime Contractor: Matra Marconi Space (UK)Responsible Organization: INPE (Brazil)

• Channel/variable subsetting and restructuringThe web-based AIRS on-the-fly/on-demand subsetter performs channel/variable subsetting and restructuring for AIRS Level 1A, Level1B and Level2 data products. One can narrow down criteria to subset data files with desired channels and variables and then download the subsetted file.

• Data miningBy using data mining, one can integrate and run user-provided data reduction algorithms to routinely generate value-added products. This type of procedure, so-called “knowledge discovery from data bases” (KDD), provides an external subsystem that interfaces with GES DISC DAAC system in a manner similar to that of other data producers.

• On-line data visualization and analysis HTML/CGI interfaces interacting with data analysis software such as IDL will allow users to search, select, analyze and manipulate data to assure data contents such as domain, parameters, data quality and physical features prior to ordering data products.

• Data format and tools support

AIRS data users will need certain tools to get full use out of AIRS data which is in HDF-EOS format. Tools that are available for reading, displaying and manipulating AIRS data will be tested and recommended to AIRS users as they become available. AIRS users will have a list of those tools from the AIRS Data Support web page. In addition, the AIRS Data Support Team will provide programs in various computer languages (e.g., C, FORTRAN, IDL, MATLAB) for this purpose.

• DAAC Search and OrderEnables users to request data efficiently through hierarchical architecture showing temporal coverage, number of items, average item size, description and browse images for the AIRS data products available. At certain levels of the hierarchy, spatial, temporal, orbital and parameter search features are provided to customize searches.

Data Access

• ECS Data PoolA new solution for distributing EOS data on-line. It will increase the distribution capacity by significantly reducing the need to access a tape archive. In addition, user accesses to the data should be made faster and easier.

• EOS Data GatewayThe EOS Data Gateway (EDG) is the interface to all data available in NASA's Earth Observation System Data Information System and related data centers. With EDG, a user can search for and

acquire a large variety of earth, ocean, and atmospheric science data obtained from EOS instruments.

• DAAC Help desk for various user questions or special requests

• Phone toll-free: 1-877-422-1222• E-mail: daacuso@daac.gsfc.nasa.gov

These informational webpages will provide access to:• Various technical documents such as

Readmes, the AIRS Guide and DIFs• Product ordering and distribution interfaces

(discussed in Data Access section)• Sample imagery and atmospheric profiles as

they become available• HDF-EOS format information and conversion

programs• Online data tools (discussed in Data Services

section)• AIRS Science Team web links at NASA JPL• Contact information for DAAC Help

AIRS L1A simulated data counts (channel 201) for September 13, 1998.

Vertical profiling features available in Online AnalySIS

(OASIS) will be particularly useful with AIRS data. Upper

air observations, such as the station rawinsonde displayed

to the right, will be used to validate AIRS data.

HSB

FACTS ABOUT AQUASize: stowed: 2.68m x 2.49 m x 6.49 m

deployed: 4.81 m x 16.70 m x 8.04 mMass: 2,934 kg (at launch)Power: 4,444 W (orbit average)Design Life: 6 yearsOrbit: Altitude: 705 km, polar, sun synchronous

Inclination: 98.2 +/- 0.1 degreesAscending node: 1:30 p.m. +/- 15

minutesPeriod: 98.8 minutes

Prime Contractor: TRWResponsible Organization:NASA

AIRS

AMSU-A1

AMSU-A2