COMPARISON OF A NEW LUNAR RADIOMETRIC MODEL BASED ON SELENE/SP WITH SATELLITE OBSERVING LUNAR IMAGES Y. 2 Ishihara , R. 1 Nakamura , S. 1 Tsuchida , T. 3 Matsunaga , Sensor-sensitivity degradation in Space Sensitivity degradation (ASTER) The long-term radiometric calibration is indispensable for quality assurance and control of data products. Sensitivity 1.0 Sever conditions of space: Outgassing, High energy particles, UV light… -> sensitivity degradation of sensors are unavoidable. 2. 3. 4. AIST, JAXA, NIES, JSS 0.8 Band 1 Band 2 0 Days since launch ・Band 3 (530 - 590 nm) ・Band 4 (640 - 670 nm) ・Band 5 (850 - 880 nm) ・Band 9 (1360- 1380 nm) Date: 2013-06-24 Phase angle: 12° Date: 2003-04-14 Phase angle: 27° [Arai et al., 2011, IJAS] 3000 1 % brightness variation  More than 1 Myr [Kieffer, 1997] Earth No atmosphere SELnological and ENgineering Explorer (SELENE) launched in 2007 & observed Moon until June 2009, operated by JAXA. Spectral Profiler (SP): a spectrometer obtaining whole Moon surface reflectance with good spectral resolution Reflectance map (752.8 nm) SELENE/SP reflectance model Radiance comparison ASTER Band 1 Correlation 0.992 coefficient Ratio (Observation / 1.05± 0.05 Model) OLI Correlation coefficient Ratio (Observation / Model) ©NASA ©NASA/USGS Band 2 Band 3 0.993 0.993 1σ 1.01± 0.04 0.95± 0.03 Band 3 Band 4 Band 5 Band 9 0.992 0.993 0.993 0.992 1.08± 0.04 1.05± 0.03 0.98± 0.03 Results of pixel by pixel radiance comparison 0.95± 0.03 Band 5/OLI Band 2/ASTER Observed vs Simulated images: - Good correlation: more than 0.99 - Small uncertainty of ratio: 1σ < 4 % → Standard errors should be much smaller (< 1 %). - Quality remains in different phase angles Simulated radiance (W/m2/μm/str] SP model has good ability to be used for evaluating relative degradation of sensors - High Spectral (VNIR: 6 nm, NIR: 8 nm) This is enough for Moon 4. Summary and future works - Well grid interval (0.5 ˚ x 0.5 ˚) observation from Earth - Spectral range: 510 – 1600 nm Summary - Photometrical dependencies on incident, emission and From the comparison between observed and modeled images, phase angles are included we have confirmed the good quality of SELENE/SP Lunar reflectance model. This model enables us to simulate any Moon observations. Reflectance Application to future hyper spectral satellite missions, such as HISUI. Wavelength [nm] Simulated Moon images on various days Purpose of this study Evaluating usefulness of a new Lunar reflectance model to utilize Moon as much as possible for radiometric calibration of satellite onboarding sensors. Specifications Spectral Range Spectral Bands Spectral Resolution Spatial Resolution Swath Width Hyperspctral Imager VNIR SWIR 400 – 970 nm 900 – 2500 nm 57 128 10 nm 12.5 nm 30 m 30 km Multispectral Imager 450 – 900 nm 4 60 – 110 nm 5m 90 km N. Ohgi et al., Japanese hyper-multi spectral mission, Proc. IEEE IGARSS, 3756-3759 (2010). 1σ Band 2/ASTER Band 5/OLI θphase~27° θphase~12° Brightness Ratio Future works Studying distribution of obs./model brightness ratio - Latitude dependency exists or not ? - Different distribution in different phase angle condition ? Normalized Frequency 2. New Lunar reflectance model based on SELENE/SP June 24, 2013 Landsat 8/OLI (9 bands) ・Band 1 (520 - 600 nm) ・Band 2 (630 - 690 nm) ・Band 3 (760 - 860 nm) Band 3 Extremely Photometrical stable [Yokota et al., 2011, Icarus] and S. 3 1. Yamamoto Simulating Satellite observations Terra/ASTER(14 bands) 0.9 0.7 No atmospheric absorption -> Ideal observation condition for radiometric calibration Y. 3 Yokota 3. Radiance comparison: Observation vs Model 1. Radiometric calibration using Moon Moon as a ideal calibration target F. 4 Sakuma , Observed radiance (W/m2/μm/str) T. 1 Kouyama , -1σ Acknowledgment: Authors greatly appreciate Dr. Jerad, USGS and Landsat8/OLI team members to provide OLI Moon observation data. References: Arai et al., Trend Analysis of Onboard Calibration Data of Terra/ASTER/VNIR and One of the Suspected Causes of Sensitivity Degradation, IJAS, 2, 2011 Kieffer, Photometric Stability of the Lunar Surface, Icarus, 130, 323-327, 1997. Yokota et al., Lunar photometric properties at wavelengths 0.5–1.6 lm acquired by SELENE Spectral Profiler and their dependency on local albedo and latitudinal zones , Icarus, 215, 639-660, 2011.