NASA GIFTS Measurement Concept OverviewNASA GIFTS Measurement Concept Overview4th Workshop on Hyperspectral Science (MURI, GIFTS, GOES-R)

University of Wisconsin – Madison (April 27-28, 2004)

20/20 Vision (Weather in Our Palm)20/20 Vision (Weather in Our Palm)

By the year 2020, mankind will have the By the year 2020, mankind will have the technology (observations and models) to technology (observations and models) to

digitize the earth’s surface and its atmosphere digitize the earth’s surface and its atmosphere with a resolution of 1 km and 1 minute with a resolution of 1 km and 1 minute

AndAnd

Every individual on earth will have personal Every individual on earth will have personal and timely access to weather observations and and timely access to weather observations and accurate weather forecasts through a “palm” accurate weather forecasts through a “palm”

computer/display unitcomputer/display unit. .

2020 Vision Strategy2020 Vision Strategy

Surface-basedRemotely Sensed

Integrated Data ProductsIntegrated Data Products

Environmental Satellites

METOP(Europe)

NPOESS(USA)

ENVISAT(Europe) EOS

(USA)

ADEOS(Japan)

FY POLAR(China)

FY GEO(China)

Hyperspectral Atmospheric Sounder EvolutionHyperspectral Atmospheric Sounder Evolution

Nimbus 3 & 4 IRIS/SIRSIRIS/SIRS

(1969-1972)

Nimbus 5/ITPRITPRITOS/ITOS/VTPRVTPR

Nimbus 6/NOAA HIRSHIRSGOES/GOES/VAS & HIRSVAS & HIRS

(1972-2009)

METOP-IASIIASI (2005- )

NPP/NPOESS/CrISCrIS(2006- )

AircraftNAST-I / SHISNAST-I / SHIS

(1995 - )

NMP NMP GIFTSGIFTSGOES-HESHES(20??- )

First Satellite Sounders

Hyperspectral Resolution

US Hyperspectral Resolution Sounder

GeostationaryImaging 4-d

T,q,“V”V” Sounder

High Resolution Interferometer Sounder (HISHIS)

(1985- )

High Horizontal Resolution

Hyperspectral Resolution Imagery

European Hyperspectral

Resolution Sounder

ADEOSIMGIMG

(1996-1997)(1996-1997)

First Satellite Hyperspectral Resolution Sounding Spectrometers

FTS Grating

AquaAIRSAIRS

(2002- )

Hyperspectral Atmospheric SoundingHyperspectral Atmospheric Sounding

The Infrared Radiance Spectrum

AIRS Hyperspectral Atmospheric SlicingAIRS Hyperspectral Atmospheric Slicing

wavenumbers (cm-1)

2000 2500 3000 3500

rela

tive

inte

nsi

ty

0

1

2

3

4

5

6

7

2129 cm-1 (4.7 µm)

2314 cm-1 (4.3µm)

2314cm-1 (high gain)

Images from Two Single Spectral Samples (Left)And Spectra from Two Different Spatial Samples (Below) Observed With a 128 x 128 Imaging FTS

Spectrum for Pixel (37,64) on face

Spectrum for Pixel (90,63) in breath

4.3 µm (2314 cm-1)CO2 Absorption Band

(3.0 µm)(5.0 µm)

Hyperspectral ImagingHyperspectral Imaging

Objective of the Geo-Sounder - Water Vapor MotionObjective of the Geo-Sounder - Water Vapor Motion

4-d Digital Camera:4-d Digital Camera:

•

Horizontal:Horizontal: Large area format Focal Plane detector Arrays

Vertical:Vertical: Fourier Transform Spectrometer

Time: Time: Geostationary Satellite

EO-3 “GIFTS”

GGeostationary IImaging FFourier TTransform SSpectrometerNew Technology for Atmospheric Temperature, Moisture, Chemistry, &

Winds

GIFTS Sampling CharacteristicsGIFTS Sampling Characteristics• Two 128x 128 Infrared focal plane detector arrays with 4 km footprint size

• Two 512 x 512 Visible focal plane detector arrays with 1 km footprint size

• Field of Regard 512 km x 512 km at satellite sub-point

• Ten second full spectral resolution integration time per Field of Regard

• ~ 80,000 Atmospheric Soundings every minute

GIFTS IR Measurements and ProductsGIFTS IR Measurements and Products

Products:Water vapor (soundings, fluxes, winds)

Temperature (sounding, stability)Carbon monoxide concentration (2 Layers)

Ozone concentration (4 Layers)Surface Temperature and emissivity

Clouds (altitude, optical depth, microphysical properties, winds)Aerosol Concentration and Depth

(8.8 to 14.6 microns) (4.4 to 6.1 microns)

Spatial Resolution130m/km flight alt.(2.6 km from 20km)

Swath Width2 km /km flight alt.(40 km from 20 km)

Water Vapor Mixing Ratio( Uncorrected)

NAST-I Validates GIFTS ConceptNAST-I Validates GIFTS Concept

Temperature (K)

Relative humidity (%)

• Instrument Characteristics – infrared Michelson interferometer (9000 spectral channels) 3.5 – 16 microns @ 0.25 cm-1

• Aircraft Accommodation – ER-2 Super pod & Proteus Underbelly pod

• Radiative Measurement Capability– calibrated radiances with 0.5 K absolute accuracy, 0.1 K precision

Tracks over ARM-site

NAST-IWater Vapor TrackingDemonstrates GIFTS

Wind Profiling Technique

δt~35 min

60 km x 40 km

WindWindMeasurementMeasurement

ER-2 NAST H2O Vs Twin Otter Doppler LIDAR Winds

0 90 180 270 360Direction (Degrees)

1000

900

800

700

0 4 8 12 16 20

Pre

ssu

re (

mb

)

Speed (mps)

February 11, 2003

36N, 121.6W

GOES - IR

X

Off California Coast

Geostationary Hyperspectral MeasurementsGeostationary Hyperspectral Measurements

Observation Capability Will Observation Capability Will RevolutionizeRevolutionize

Weather ForecastingWeather Forecasting

• Hurricane landfall (steering wind profiles)

• Tornadic storms (stability change monitoring)

• Nowcasting (rapid measurement update)

• Numerical prediction (initial p,T,q,V data)

• Air quality forecasts (O3 and CO transport)

What About Clouds ????

Cloud Effects on RetrievalCloud Effects on Retrieval

Cloud Tops Moist Layers

PBL Ht

Cloud Tops

OpaqueClouds

Non-opaqueClouds

Non-opaqueClouds

NAST I-HOP June 12, 2002 Over Oklahoma

Cirrus Cloud “Venetian Blind Effect”Cirrus Cloud “Venetian Blind Effect”

•

These retrievals, uncorrected for cloud attenuation, demonstrate the ability of a high spatial resolution

sounder to sense the spatial structure of moisture below a scattered and semi-transparent cirrus cloud cover

16.0 UTC

14.9

13.8Depressions due to Cloud Attenuation

Tem

perat u

re ( K)

Log

10 { VM

R (g/K

g)}

Basis for Cloud Training Algorithm!Basis for Cloud Training Algorithm!Radiance Spectra Carry Information on Cloud Phase

and Microphysical Properties

Wavenumber (cm-1)

Cloud Retrieval Training !Cloud Retrieval Training !• Perform a realistic simulation of clouds for synthetic EOF radiance training• Diagnose cloud layer from radiosonde relative humidity profile

– A single cloud layer (either ice or liquid) is inserted for the highest level of cloud diagnosed from the input radiosonde profile. If a second cloud layer exists it is represented as an opaque cloud.

• Use parameterization of Heymsfeld’s* balloon and aircraft cloud microphysical data base (2003) to specify cloud effective particle radius, re,

and cloud optical depth, , (i.e., re= a / [ - b]) .– Different habitats can be specified (Hexagonal columns assumed here)– Different clouds microphysical properties simulated for same radiosonde using random number generator to specify visible cloud optical depth within a pre-specified range. 10 % random error added to parameterized effective radius to account for real data scatter.

• Use UW/Texas A&M “lookup table” for cloud radiative properties– Spectral transmittance and reflectance for ice and liquid clouds interpolated from multi-dimensional look-up table based on DISORT multiple scattering calculations for the (wavenumber range 500 – 2500 cm-1, zenith angle 0 – 80 deg., Deff (Ice: 10 – 157 um, Liquid: 2 – 100 um), OD(vis) (Ice: 0.04 - 100, Liquid 0.06 – 150)

• Compute EOFs and Regressions from cloudy radiance data base– Regress cloud properties (i.e., p, , re) and profile against Radiance EOFs

– For small optical depth, output entire profile– For large optical depth, output profile above the cloud level

Heymsfield, A. J., S. Matrosov, and B. A. Baum: Ice water path-optical depth relationships for cirrus and precipitating cloud layers. J. Appl. Meteor. October 2003

December 5, 2003

MHX MHX

ConclusionsConclusions• The GIFTS hyperspectral measurement concept for observing temperature, water vapor flux, and wind profiles has a solid theoretical and airborne validated foundation.

• Clouds should not severely limit the utility of the GIFTS measurement concept

• The next generation operational GOES-R sounding system is benefiting from the scientific research and technology development conducted under the GIFTS program

• Although the completion of a space qualified GIFTS instrument for space validation of the GIFTS measurement concept awaits funding from a space flight geostationary satellite mission opportunity, the research and development will continue in support of the world’s next generation global observing system.