Advanced radiometry measurements and Earth science applications with the Airborne Prism Experiment (APEX)

REMOTE SENSING OF ENVIRONMENT

卷:158

Article

Schaepman, Michael E.¹  Jehle, Michael¹  Hueni, Andreas¹  D'Odorico, Petra¹  Damm, Alexander¹  Weyerrnann, Jurg¹  Schneider, Fabian D.¹  Laurent, Valerie¹  Popp, Christoph²  Seidel, Felix C.³  Lenhard, Karim⁴  Gege, Peter⁴  Kuechler, Christoph⁵  Brazile, Jason⁶  Kohler, Peter⁶  De Vos, Lieve⁷  Meuleman, Koen⁸  Meynart, Roland⁹  Schlaepfer, Daniel¹⁰  Kneubuhler, Mathias¹  Itten, Klaus I.¹ 

[1] Univ Zurich, Remote Sensing Labs, CH-8057 Zurich, Switzerland

[2] Smithsonian Inst, NMNH, Washington, DC 20013 USA

[3] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA

[4] Earth Observat Ctr, German Aerosp Ctr, D-82234 Oberpfaffenhofen, Wessling, Germany

[5] RUAG Schweiz AG, RUAG Aviat, CH-6032 Emmenbrucke, Switzerland

[6] Netcetera AG, CH-8004 Zurich, Switzerland

[7] OIP Sensor Syst, B-9700 Oudenaarde, Belgium

[8] VITO, B-2400 Mol, Belgium

[9] ESA ESTEC, NL-2201 AZ Noordwijk, Netherlands

[10] ReSe Applicat Schlapfer, CH-9500 Wil, Switzerland

关键词: Imaging spectroscopy;    Earth observation;    APEX;    Calibration;    Processing;    Validation;    Earth science applications;   

DOI  :  10.1016/j.rse.2014.11.014

来源: Elsevier

【 摘 要 】

We present the Airborne Prism Experiment (APEX), its calibration and subsequent radiometric measurements as well as Earth science applications derived from this data. APEX is a dispersive pushbroom imaging spectrometer covering the solar reflected wavelength range between 372 and 2540 nm with nominal 312 (max. 532) spectral bands. APEX is calibrated using a combination of laboratory, in-flight and vicarious calibration approaches. These are complemented by using a forward and inverse radiative transfer modeling approach, suitable to further validate APEX data. We establish traceability of APEX radiances to a primary calibration standard, including uncertainty analysis. We also discuss the instrument simulation process ranging from initial specifications to performance validation. In a second part, we present Earth science applications using APEX. They include geometric and atmospheric compensated as well as reflectance anisotropy minimized Level 2 data. Further, we discuss retrieval of aerosol optical depth as well as vertical column density of NOx, a radiance data-based coupled canopy atmosphere model, and finally measuring sun-induced chlorophyll fluorescence (Fs) and infer plant pigment content. The results report on all APEX specifications including validation. APEX radiances are traceable to a primary standard with <4% uncertainty and with an average SNR of >625 for all spectral bands. Radiance based vicarious calibration is traceable to a secondary standard with <= 65% uncertainty. Except for inferring plant pigment content, all applications are validated using in-situ measurement approaches and modeling. Even relatively broad APEX bands (FWHM of 6 nm at 760 nm) can assess Fs with modeling agreements as high as R-2 = 0.87 (relative RMSE = 27.76%). We conclude on the use of high resolution imaging spectrometers and suggest further development of imaging spectrometers supporting science grade spectroscopy measurements. (C) 2014 The Authors. Published by Elsevier Inc.

【 授权许可】

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