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Summary of Proposal Work Done at UAH to Set the Lunar Flux Scale. Workshop on Satellite Calibration for Climate Change Research David B. Pollock. Topics. Status of absolute and relative lunar flux uncertainties?
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Summary of Proposal Work Done at UAH to Set the Lunar Flux Scale Workshop on Satellite Calibration for Climate Change Research David B. Pollock Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Topics • Status of absolute and relative lunar flux uncertainties? • How to improve the absolute accuracy of the Lunar flux (data to develop moon as a standard to meet the requirements of the climate change research)? • Is there a need to extend lunar observations to the infrared and what are the benefits for climate change research. • Ideas to implement solutions to use moon as a standard • What other ancillary radiometric measurements could be made and benefits could be derived while measuring the lunar flux from above the atmosphere? Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Proposal Effort Summary • Background • Work began as a proposal to NSF in response to Solicitation 04-522, due 2/26/04. • 5 year cost estimate $3.9 M >> $2.5 M NSF cost limit. • Proposal halted 2/18/04. • Response from relevance inquires to NSF • Very important, but not relevant the NSF 04-522 solicitation, • Encouraged to discuss work with Atmos. Sci. Prgm. Mgr. Dr. Moyers • Support dollars needed to keep team together while NSF customer courted. • A plus-up from Congress would help. • No help found. Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
BLAIRBalloon Lunar Absolute Irradiance Radiometer A $4M dollar research opportunity. 4/1/2004 Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Goal • Uncertainty SI < 2% will begin to eliminate the deficiency of exo-atmospheric radiometric standards, 300 to 2400 nm spectral region. Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
2005 - Relative and AbsoluteLunar Flux Data Uncertainty • The ROLO lunar data is stable to better than 0.1% * • There is a significant wavelength dependent uncertainty 5 – 15% SI. • There is a bias ~ 6% when compared to satellite instrument measurements. * Hugh H. Kieffer et al, On-orbit Calibration Over time and Between Spacecraft Using the Moon, SPIE 4881. Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Error Budgets Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Participants - Responsibilities • UAH (CAO and ECE) - PI, Radiometer, Pointing and ground station • HARC - Balloon launch and recovery • SDL - Repeated calibrations • TBE - Payload fab, integ & qual test • USGS - Side-by-side measurements at ROLO and data analysis • NASA GSFC - Peer review and critique. Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Costs Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
NSF Interest Solicitation November 4, 2004 Dr. Jarvis L. Moyers Division Director Division of Atmospheric Sciences, 775 S RE: Letter of inquiry dated February 18, 2004 Dear Dr. Moyers, Thank you for your response to the letter of inquiry February 18, 2004. Would the NSF consider an un-solicited proposal for either a high altitude balloon or aircraft program to directly tie the RObotic Lunar Observatory, ROLO, Lunar Flux Model to the International System of Units via the NIST high accuracy cryogenic radiometer, the HACR. This work is to support past as well as future radiometric calibrations for space-based observations of climate parameters. An estimated total program cost is in the $4 to $5M range. The basic concept is build as simple and as stable a filter radiometer as technologically feasible and gather statistically significant data sets from above most of the atmosphere, with NIST calibration immediately before and after each flight. In addition to three to five flights, there would be initial and final concurrent observations at the ROLO site. A NIST transfer device would provide the traceable path to SI units via the HACR. Specific programs that would benefit from this work include SeaWiFS, ASTER, MODIS, ALI, MTI, Hyperion, MISR, and any NPP or NPOESS instrument that can view the Moon, e.g., VIIRS; Figure 1. Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Figure 1 (Data/Model -1) %, Average of Data per Instrument. Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change Thomas C. Stone, USGS & Hugh H. Kieffer, Celestial Reasonings
NSF Response Professor Pollock, If you have prepared your proposal in accordance with the guidelines in NSF 04 522 then by all means go ahead and submit it by the published deadline. The accuracy of atmospheric data used for atmospheric sciences research is also a matter of importance to us. You should be aware that this is likely to be a very competitive solicitation as interest in this topic is currently very keen in the science and engineering communities. Jarvis Moyers Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Notes from a conversation with Danny Ball, site manager at the National Scientific Balloon Facility on Friday, 16 April 2004. • A 75 kg payload carried to 25 km altitude is trivial. • The standard balloon sizes are 4 to 60 x 106 ft3 and anything smaller than 4 x 106 ft3 is a special. • Altitudes in the 25 to 30 km range are “small change”. • A 60 x 106 ft3 balloon will reach 45 km altitude and is 700 ft diameter. • A 60 x 106 ft3 balloon costs $180K and a 4 x 106 ft3 balloon costs $35K. • A 70 ft diameter parachute, for the smallest balloon payload, attaches directly to the balloon and is 110 ft long. There is a 65 ft cable ladder below the parachute. The payload attach point is the end of the ladder. If additional distance between the balloon and the payload is needed a second ladder can be added or a reel-down installed. The reel-down is 50 to 1000 ft in length. • A standard 4 x 106 ft3 balloon will carry a 200 kg payload to 33 km and the cost is $35K. A standard 4 x 106 ft3 balloon will lift up to 1500 kg. • A night launch out of Palestine in the June through August time period is routine. • There are no operational fees beyond the expendables. Expendables run about $50K per launch for a 4 x 106 ft3 balloon. Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Notes Continued • The 65 ft cable ladder provides torsional stiffness to push against for azimuth rotation. Three arc-second pointing has been achieved hanging from a balloon. • The atmospheric guys at JPL may have a payload frame we could borrow. • There is a standard Consolidated Instrument Package available. • NSBF will track the payload. • They will terminate the flight. • They will recover the payload. • The CIP will collect and record the data. • The CIP can be used to send commands. • The NSBF requirements are • A stress analysis that shows the payload can survive 10 g vertically (parachute opening) and 5 g @ 45° (landing), • For a simple gondola, a hand calculation is adequate, • An electronics compatibility test pre-launch. • Users outside the NASA community will be charged for expendables and a nominal user fee all payable to Wallops Island, VA. • The process to get on the NSBF schedule starts with a request for a Flight Request Form. Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Topics • Status of absolute and relative lunar flux uncertainties? • How to improve the absolute accuracy of the Lunar flux (data to develop moon as a standard to meet the requirements of the climate change research)? • Is there a need to extend lunar observations to the infrared and what are the benefits for climate change research. • Ideas to implement solutions to use moon as a standard • What other ancillary radiometric measurements could be made and benefits could be derived while measuring the lunar flux from above the atmosphere? Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Topics • The problem • Working on a solution Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
B A2 = P2 + B2 + (SNR)-2 + “T” 2 Total Uncertainty • Operational envelope • Critical parameters and functions • Relative spectral response, in-, out-of-band. • Absolute response • Saturation response • Dark off-set • Non-linearity of response vs temperature • Relative response over field of regard • Distortion map over field of regard • Response vs array, electronics temperature • Focus (energy on a pixel) • Pixel fill-factor • Response to out-of-field-of-view sources • Gain normalization • Repeated observations - Taylor, B.N., Kuyatt C. E., Guidelines for Evaluating and Expressing the Uncertainty of NIST Measurement Results, NIST Technical Note 1297, 1994 Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
International System of Units, SI Convention of the Metre National Measurement Institutes Transfer radiometers Reference sources Calibration sources Sun, Moon, Stars, Terrestrial Remote sensors Orbital, Airborne, Terrestrial HeuristicSI Traceability* Path * “Property of the result of a measurement … whereby it can be related to stated references… through an unbroken chain of comparisons all having stated uncertainties.” International Vocabulary of Basic and General Terms in Metrology (VIM), Estler, CALCON 2004 Workshop Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Current Path • Transfer measurements in situ. • A set of measurements of Vega at 0.5556 m.* • Data analysis, multiple observers, instruments and sites. Vega Pt or Au point cavity, inside dome, after telescope optics. Striplamp, hundreds of meters distant *Hayes, Calibration of Fundamental Stellar Quantities, Proc. IAU Symposium No. 111 (1985) Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Stars Moon ALIR @ 12 -45 km SDL ROLO & ALIR (TBD)XR NIST - SI Units Planned Path • Polychromatic to span the ROLO range, 0.34 – 2.4 m. • Combined ROLO bands. • Individual, fixed bandpass filters. • HACR – (TBD)XR – MIC – ALIR • Joint ROLO & ALIR observations. • Repeated ground calibrations. • Analysis Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Topics • The problem • Working on a solution for the Lunar Irradiance Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Rationale • What – Reduce the ROLO Lunar Irradiance Model uncertainty. • Why – Remote sensors are being tasked to produce ever more accurate data. • How – Iterative calibrations, coupled with comparative measurements in the field and laboratory. • Who – Trained, qualified participants. • When – Needed now. Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Aperture stop Field stop Entrance pupil 19 bandpass filters + Blank Near aperture stop Detectors ALIR FOV = 0.5 F No. = 10 • Selectable band pass filters • Calibrated at NIST • Common to ROLO • Located near aperture stop • High out-of-field light rejection • Hard field & aperture stops • Internal reference source to • monitor stability Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
ROLO Bands, 32 Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
ROLO Bands Combined,19 Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Dynamic Measurement Range Small Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
S/N, 1 cm Aperture, Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Field-of-view edge Spurious Flux Control Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Command &Control Acquisition / Track Housekeeping ALIR Data storage and transmission Az-El Gimbals ECI Position Flight System Balloon Aircraft or Ground station Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Estimated Parameters Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Schedule Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Management Plan Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Trained, Qualified Participants • SI traceable path • NIST • Space Dynamics Laboratory • USGS • Iterative flights • Balloon, National Scientific Balloon Facility • Aircraft, SOFIA • Payload & Operations – UAH • Data Analysis – USGS, UAH • Peer review and critique – NASA GSFC Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Activities • Stabilization, pointing and position. • Alt-az gimbals w/ 1” pointing, build or borrow. • GPS and lunar ephemeris from vehicle. • Balloon, routine • > 25 km w / a 4 x 106 ft3 volume. • 70 ft diameter by 110 ft long parachute. • Payload attached to the end of 65 ft cable ladder below the parachute. • Added distance between balloon - payload possible w / a second ladder or a 1000’ reel-down. • Aircraft SOFIA. • 12.5 – 13.5 km • 3+ years away • Repeated pre-, post-flight Sensor calibrations. • Concurrent observations w / ROLO telescopes in Flagstaff. • Data reduction and error analysis • Statistically significant data set • 100 s data on 30 successive days or 100 s on 12 selected days / year • Ingest archive data Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Conclusion • A relatively small, < 5 cm aperture, well baffled, <10-11 @ 1, multi-spectral, 340 – 2,400 nm radiometer, limited dynamic range, <2, is feasible. • Setting the ROLO Model scale < 2% is a reasonable task. Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Backup Charts Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
This page and the next as well as many of the preceding pages are from the CALCON Presentation of August 26, 2004. Reducing the RObotic Lunar Observatory (ROLO) Irradiance Model Uncertainty SI David B. Pollock1, Thomas C. Stone2, Hugh H. Kieffer3, Joe P. Rice4 1. The University of Alabama in Huntsville, 301 Sparkman Drive, OB 422, Huntsville, AL 35899 2. U.S. Geological Survey, 2255 N. Gemini Drive, Flagstaff, AZ 86001 3. Celestial Reasonings, 2256 Christmas Tree Lane, Carson City, NV 89703 4. National Institute of Standards and Technology, 100 Bureau Drive, MS 8441, Gaithersburg, MD 20899-8441 Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change
Abstract There is a fundamental remote sensing problem, the inability to identify and to correct biases to the level that current sensor technology permits once a sensor becomes operational in-orbit. This paper presents a concept, retrieval and recalibration of a transfer standard, to reduce in the longer term the uncertainty of the flux from the stars, the solar flux and vicarious sources on the earth using the RObotic Lunar Observatory, ROLO, Irradiance Model as the basis for a technology demonstration. The cause of the fundamental remote sensor problem is the uncertainty of the respective fluxes traced to the International System of Units, SI. This includes the sensors relative to the U. S. Global Climate Change Research Program (U.S. GCRP), sensors for NASA, NOAA, TVA, DoD, DOE, HHS, NSF, USDA, DOI and EPA. An effort to solve this fundamental problem began about 7 years ago with the emergence of the problem at a NIST Workshop in the fall of 1997 and stated in NIST GCR 98-748, High Accuracy Space Based Remote Sensing Requirements, March 1998. Since then there has been expanding recognition and discussion of this remote sensing deficiency at National and International conferences and workshops. Remote sensor data shows that remote sensors are on the order of 4 to 5 times more stable than the uncertainty of either the spectral or total radiant flux from the moon, the stars and the sun. The consequence is data uncertainty increases because there are not adequately uncertain calibration sources available to remove the remote sensor biases that arise during operations. The concept presented by this paper when implemented would begin an effective, systematic attack on the larger problem, the stars, the sun and terrestrial, by attacking a most glaring deficiency of the recognized, accepted ROLO Lunar Irradiance model. Although the lunar data is stable to better than 0.1% there is a significant wavelength dependent uncertainty on an absolute scale thought to be on the order of 5 – 15% SI. A bias of up to 6% is found when results are compared to satellite instrument measurements. Reducing this uncertainty SI will begin to eliminate the deficiency of exo-atmospheric radiometric standards specifically for those remote sensors that can use the lunar flux over the 300 to 2300 nm spectral region for calibration. Workshop - Moon as a Standard for Satellite Sensor Calibration for Climate Change