Martin G. Mlynczak Climate Science BranchNASA Langley Research CenterASIC3 WorkshopFar-Infrared Spectroscopy of the Troposphere FIRST16 May 2006

FIRST Team and SponsorsTechnology Development and Flight Demonstration Team

Marty Mlynczak NASA Langley Dave Johnson NASA Langley Charlie Hyde NASA Langley Stan Wellard Utah State/SDLGail Bingham Utah State/SDLMike WatsonUtah State/SDLHarri LatvakoskiUtah State/SDL Ken Jucks Smithsonian Astrophysical Observatory Wes Traub Smithsonian Astrophysical Observatory Jess LanderosJPLJim MargitanJPLBill Stepp & TeamColumbia Scientific Balloon Facility

Science Advisory Team

Dave Kratz NASA Langley Ping YangTexas A & M UniversityBill Smith U. Wisconsin Lou Smith NIAPaul Stackhouse NASA Langley Chris Mertens NASA Langley Bob Ellingson Florida State UniversityRolando Garcia NCAR ACD Bill Collins NCAR CGD Brian Soden GFDL John Harries Imperial College, London Rolando Rizzi U. Bologna, ItalySponsors and Supporters

NASA Earth Science Technology OfficeKen AndersonGeorge KomarCarl WagenfuehrerBrian Killough (LaRC)

NASA Science Mission DirectorateHal MaringJack KayeMike KuryloDon AndersonPhil DeCola

Outline Science Motivation and Justification for far-IR FIRST Sensor Overview

FIRST Flight Summary and Performance Assessment

Future plans and directions to spaceflight

FORGE and RHUBC campaigns FIDTAP

SummaryFar-Infrared Spectroscopy of the Troposphere

Far-Infrared Spectroscopy of the TroposphereA Brief History of Earth Radiation Budget MeasurementsERB measurements from space first proposed by V. Suomi in late 1950s

First quantitative measurement of Earth System from space was ERB in late 1950s, early 1960s

Measurement is of 2 classic energy flows:1. Total Radiation = Emitted Thermal + Reflected Solar2. Reflected Solar Radiation Emitted thermal radiation obtained by subtraction of classic energy flows

In the past 40 years these measurements have been refined in terms of:1. Improved spatial resolution2. Improved calibration 3. Improved angular sampling

Two critical dimensions remain temporal (GERB) and spectral

Far-Infrared Spectroscopy of the TroposphereFar-IRMid-IR

Far-Infrared Spectroscopy of the Troposphere Up to 50% of OLR (surface + atmosphere) is beyond 15.4 mm

Between 50% and 75% of the atmosphere OLR is beyond 15.4 mm

Basic greenhouse effect (~50%) occurs in the far-IR

Clear sky cooling of the free troposphere occurs in the far-IR- Potential to derive atmospheric cooling rates directly from the radiances

Upper Tropospheric H2O radiative feedbacks occur in far-IR

Cirrus radiative forcing has a major component in the far-IR

Longwave cloud forcing in tropical deep convection occurs in the far-IR

Improved water vapor sensing is possible by combining the far-IR and standard mid-IR emission measurementsDirect Observation of Key Atmospheric ThermodynamicsCompelling Science and Applications of the Far-Infrared

Far-Infrared Spectroscopy of the TroposphereAnnual mean TOA fluxes for all sky conditions from the NCAR CAM Reference: Collins and Mlynczak, Fall AGU, 2001

Far-Infrared Spectroscopy of the TroposphereAnnual mean TOA fluxes for clear-sky conditions from the NCAR CAM.Reference: Collins and Mlynczak, Fall AGU, 2001

Far-Infrared Spectroscopy of the TroposphereMid-IRFar-IRClear-Sky Spectral Cooling Rate

Far-Infrared Spectroscopy of the TroposphereObservedUnobservedSpectrally Integrated Cooling Mid-IR vs. Far-IR

FIRST Sensitivity to Cirrus CloudsBrightness temperature difference between two channels n1=250.0 cm-1 and n2=559.5 cm-1 as a function of effective particle size for four cirrus optical thicknesses FIRST spectra can be used to derive optical thickness of thin cirrus clouds (t < 2). Reference: Yang et al., JGR, 2003

Far-IR Measurements in our Solar SystemFar IR least measured from space on Earth!Nimbus III/IV, 1969/70Hanel et al., 2003

FIRST System Performance RequirementsAt present, no extant sensor in development for spaceflight with spectral sensing capability longer than 15 mm wavelength

FIRST developed technology needed to attain daily global coverage, from low-earth orbit, of the far-infrared spectrum (10 km IFOV from 900 km)

Spectral coverage: 10 to 100 mm (1000 to 100 cm-1)Requires bilayer beamsplitter with > 92% efficiency 10-100 mm

Spectral Resolution: 0.625 cm-1 (unapodized), 0.8 cm OPD

Scan time 1.4 s

NEDT: 0.2 K (10 to 60 mm); 0.5 K (60 to 100 mm)

Optical throughput:Sufficient to meet the NETD requirement for 100 fields in 1.4 s (10 x 10 array)

Technology to be demonstrated in space-like environmentFIRST Developed under NASAs Instrument Incubator Program (IIP)

FIRST Key Technology RequirementsInstrument Type: Fourier Transform Spectrometer Gives greatest possible span of wavelengths in a single instrument

Beamsplitter: Germanium on polypropyleneExcellent response in far-IR, minimal absorption features

Detectors with kilohertz sampling frequenciesTo record > 1000 samples in ~ 1 second from orbit

Single focal planeTo simplilfy the optical design and calibration

Complete system to be deployed on a high altitude balloon To simulate the space environment

FIRST Interferometer Block DiagramCarriageSectionBeamsplitterRemoteAlignmentStationary mirrorTranslating mirrorTach/Torque motorBeam SplitterSection

FIRST Interferometer Cube and Mirror Drive AssemblyScene Radiance

FIRST Interferometer Cube

FIRST Broad Bandpass Beamsplitter4 x RTFIRST beamsplitter in mounting ring at USU/SDLExample FIRST beamsplitterperformance curves

Sample relative response curves (taken with SAO FIRS-2)

FIRST Focal Plane LayoutPerformance of Center (1, 10) and corner (4, 5) detectors will be usedto demonstrate that FIRST has sufficient throughput to meet the NETD requirement for a 10 x 10 array

FIRST Balloon Payload SystemInterferometer CubeAft OpticsLN2 VolumeBeamsplitterPolypropylene Vacuum WindowRemote Alignment AssemblyScatter FilterScene Select MirrorScene Select MotorInterdewar WindowActive LN2 Heat ExchangerPassive LN2 Heat Exchanger

FIRST Scene Select AssemblyScene Select MirrorStepper MotorOptical EncoderMechanical Limit Switch (3)Scene Select Mirror BaffleBearingsFlex Coupling

FIRST Balloon Payload SystemSensor DewarDewar Interface PlatePlumbing / Vacuum PortInterferometer Laser BoxIn-Flight BlackbodyScene Select Assembly

FIRST CalibrationFIRST designed with absolute calibration in mind, from the start

Instrument cooled to 180 K to simulate space environment and reduce instrument background

Full field external calibration sources

Multiple calibration sources (warm, cold) in laboratory

Multiple calibration sources in flight (warm, space)

Spectral range designed to cover 10 15 mm (+ far-IR)Allows verification against standard instruments, e.g, AIRS, AERI, in mid-IR

FIRST Space View SimulatorLN2 TankLHe Tank77-95K Surface6-12K SurfaceProvide a cold source for calibration (

FIRST 300K In-Flight BlackbodyCylinder HeaterCone HeaterG-10 Support / Thermal LeakElectrical ConnectorsCone Temperature SensorBaffleMLI Blanketing

FIRST on the Flight Line June 7 2005

FIRST Flight SpecificsLaunched on 11 M cu ft balloon June 7 2005

Float altitude of 27 km

Recorded 5.5 hours of data

1.2 km footprint of entire FPA; 0.2 km footprint per detector

15,000 interferograms (total) recorded on 10 detectors

Overflight of AQUA at 2:25 pm local time AIRS, CERES, MODIS

Essentially coincident footprints FIRST, AQUA instruments

FIRST met or exceeded technology development goals

FIRST, AIRS, CERES comparisons in window imply excellent calibration (better than 1 K agreement in skin temperature)

FIRST records complete thermal emission spectrum of the Earth at high spatial and spectral resolution

FIRST First Light Spectrum

FIRST Spectrum, Center DetectorMlynczak et al., GRL, 2006

FIRST Spectrum, Corner DetectorMlynczak et al., GRL, 2006

Comparison of AIRS, FIRST in Window RegionMlynczak et al., GRL, 2006

FIRST Spectra Compared with L-b-L SimulationDemonstration of FIRST Recovery of Spectral StructureNote: FIRST, LbL spectra offset by 0.05 radiance units

FIRST Measured, Calculated RadianceMlynczak et al., GRL, 2006

FIRST Spectra Comparisons with L-B-L using AIRS RetrievalsL-b-L does not yet include FIRST Instrument Response Functions

FIRST Performance Assessment

Project finished on time and within budget

Spectra on Corner, Center detectors verify optical throughput requirement met (0.47 cm2 sr)

Spectral coverage (50 to 2000 cm-1) verify spectral response requirement exceeded

Calibration appears to be within 1-2 K of 3 NASA spaceflight sensors (MODIS, AIRS, CERES) calibration met to first orderIn-depth analysis of accuracy, precision, and noise underway

FIRST system now at TRL-6 and ready for science flights/campaigns

FIRST Future Directions Confirmation of far-IR calibration RHUBC Radiative Heating in Underexplored Bands CampaignFORGE: Far-IR Observations of the Radiative Greenhouse EffectZenith view, ground based with multiple instrumentsAERI, FIRST, TAFTS (UK)Cold, dry conditions at altitude (few km)See spectral development in far-IR to ~ 300 cm-1See blackbody spectrum at lower wavenumbersDerive radiative cooling of mid-troposphereObserve far-IR optical properties of cirrus in windowsValidate far-IR water vapor spectroscopy

Development of Far-IR Radiometric StandardsFIRST low-temp blackbodies

Detector development FIDTAP Achieve fast, broadband detectors capable of operation at temps > 10 K

FIRST Simulated Zenith Radiance

FIRST Simulated Zenith Radiance

FIRST Status and SummaryFIRST successfully completed technology demonstration flight 6/2005Met or exceeded technology goals now at TRL/6Combined sounder and radiation budget capabilities

Awaiting opportunity for spaceflight proposal

Continue to improve calibration and related technologies:Develop improved radiometric standards Compare extant far-IR spectral instrumentsDevelop remaining technology (detectors)Validate cryo-cooler (> 10 K) technology for flight

FIRST Lands Safely after a Successful Flight

FIRST BibliographyFormal PublicationsMlynczak, M. G., D. G. Johnson, H. Latvakoski, K. Jucks, M. Watson, G. Bingham, D. P. Kratz, W. A. Traub, S. J. Wellard, and C. R. Hyde, First light from the Far-Infrared Spectroscopy of the Troposphere (FIRST) instrument, Geophys. Res. Lett., doi:10.1029/2005GL025114. Conference Proceedings and Presentations through Calendar Year 2005Mlynczak, M. G., D. G. Johnson, H. Latvakoski, K. Jucks, M. Watson, G. Bingham, W. Traub, S. Wellard, and C. R. Hyde, FIRST Instrument description, performance, and results, Fall Meeting, American Geophysical Union, San Francisco, CA, paper IN13B-1084, 2005. Liu, X., M. G. Mlynczak, D. G. Johnson, D. Kratz, H. Latvakoski, and G. Bingham, Atmospheric Remote Sensing using FIRST, World Scientific and Engineering Academy and Society (WSEAS) Meeting, Venice, Italy, 2005. Bingham, G.E., H. Latvakoski, S. Wellard, D. Garlick, M. Mlynczak, D. Johnson, W. Traub, K. Jucks. 2005. Far-infrared spectroscopy of the troposphere (FIRST): sensor calibration performance. International Symposium on Remote Sensing of Environment. St. Petersburg, RU. June 20 24, 2005. M. G. Mlynczak, D. G. Johnson, G. E. Bingham, K. W. Jucks, W. A. Traub, L. Gordley, P. Yang, The far-infrared spectroscopy of the troposphere project, SPIE Fourth International Asia-Pacific Environmental Remote Sensing Symposium, Honolulu, HI, 2004. Kratz, D. P., Mlynczak, M. G., Johnson, D. G., Bingham, G. P., Traub, W. A., Jucks, K., Hyde, C. R., Wellard, S., FIRST, The Far-Infrared Spectroscopy of the Troposphere Project, Fall AGU Meeting, San Francisco, CA Paper SF43A-0782, 2004.

FIRST BibliographyG. E. Bingham, Harri M. Latvakoski, Stanley J. Wellard, MartinG. Mlynczak, David G. Johnson, Wesley A. Traub, and Kenneth W. Jucks, Far-infrared spectroscopy of the troposphere (FIRST): sensor calibration performance. SPIE Fourth International Asia-Pacific Environmental Remote Sensing Symposium. Multispectral and Hyperspectral Remote Sensing Instruments and Applications II. Paper 5655-25. Honolulu, HI, USA, 2004. Bingham, G.E.,, H.M. Latvakoski, S.J. Wellard, M.G. Mlynczak, D.G. Johnson, W.A. Traub, and K.W. Jucks, Far-infrared spectroscopy of the troposphere (FIRST): sensor development and performance drivers. Optical Spectroscopic Techniques and Instrumentation for Atmospheric and Space Research V. International Symposium on Optical Science and Technology, SPIE, v. 5157, San Diego, CA. August 7-8, 2003. Mlynczak, M., D. Johnson, G. Bingham, K. Jucks, W. Traub, L. Gordley, and J. Harries, The far-infrared spectroscopy of the troposphere (FIRST) project, IGARSS 2003, Toulouse, France. Invited, July 2003. Bingham, G.E., and H. M. Latvakoski, Far Infrared Technology Development for Space Surveillance, Space Based EO/IR Surveillance Technology Conference Kirtland Air Force Base, Albuquerque, NM. May 13-15, 2003. Bingham, G.E., S.J. Wellard, M.G. Mlynczak, D.G. Johnson, W.A. Traub, and K.W. Jucks, Far InfraRed Spectroscopy of the Troposphere (FIRST): Sensor Concept, Asia-Pacific SPIE 02, Hangzhou, China, Paper 4897-23, 2002.Mlynczak, M. G., D. Johnson, E. Kist, D. Kratz, C. Mertens, and W. Collins, Far-Infrared Spectroscopy of the Troposphere, Fall Meeting, American Geophysical Union, San Francisco, December 2001.Collins, W. D., and M. G. Mlynczak, Prospects for measurement of far-infrared tropospheric spectra: Implications for climate modeling, Fall Meeting, American Geophysical Union, San Francisco, December, 2001.

FIRST BibliographyMlynczak, M. G., J.E. Harries, R. Rizzi, P. W. Stackhouse, D. P. Kratz, D. G. Johnson, C. J. Mertens, R. R. Garcia, and B. Soden, The far-infrared: A frontier in remote sensing of Earths climate and energy balance, in Optical Spectroscopic Techniques, Remote Sensing, and Instrumentation for Atmospheric and Space Research IV, Allen M. Larar and Martin G. Mlynczak, Editors, Proceedings of SPIE, Vol 4485, 150-158, 2001. Mertens, C. J., Feasibility of retrieving upper tropospheric water vapor from observations of far-infrared radiation, in Optical Spectroscopic Techniques, Remote Sensing, and Instrumentation for Atmospheric and Space Research IV, Allen M. Larar and Martin G. Mlynczak, Editors, Proceedings of SPIE, Vol 4485, 191-201, 2001. Kratz, D. P., High resolution modeling of the far-infrared, in Optical Spectroscopic Techniques, Remote Sensing, and Instrumentation for Atmospheric and Space Research IV, Allen M. Larar and Martin G. Mlynczak, Editors, Proceedings of SPIE, Vol 4485, 171-180, 2001. Johnson, D. G., Design of a far-infrared spectrometer for atmospheric thermal emission measurements, in Optical Spectroscopic Techniques, Remote Sensing, and Instrumentation for Atmospheric and Space Research IV, Allen M. Larar and Martin G. Mlynczak, Editors, Proceedings of SPIE, Vol 4485, 220-224, 2001.

Intro slideFIRST Science Team Whos on FIRST Show this primarily to indicate the large scientific team supporting far-IR measurementsWill give a backgrond of the far-IR, then concentrate onour technology, and then look to the future beyond IIP. Classic approaches still followed today

Need spectral and temporal. Classic spectrum define mid and far-IRNational AnthemNCAR CAM far-IR really is important