Mineral Luminescence Observed From Space
Phillipp Koehler1, Woodward Fischer1, George Rossman1, John Grotzinger1, Russell Doughty1, Yujie Wang1, Yi Yin1, Christian Frankenberg1,2
1Division of Geological and Planetary Sciences
California Institute of Technology,
Pasadena, CA, USA
2Jet Propulsion Laboratory, California Institute of Technology,
Pasadena, CA, USA
Abstract
Methods developed to explore the luminescent properties of the moon
facilitated the development of techniques to infer terrestrial
solar-induced chlorophyll fluorescence (SIF) from satellite instruments.
While single SIF retrievals are inherently noisy, averaging many
retrievals allows us to obtain highly accurate estimates. We
analyzed several years of aggregated SIF data collected by the
TROPOspheric Monitoring Instrument (TROPOMI) and the Orbiting Carbon
Observatory-2 (OCO-2) over non-vegetated areas to explore the potential
of SIF retrievals beyond the realm of photosynthesis. The fundamentally
different retrievals at varying wavelengths in the near-infrared reveal
that about 10% of all barren surfaces are weakly luminescent, while a
few areas luminesce strongly- amounts comparable to SIF from vegetation. By
means of lithological maps, we attribute the strongest luminescence
signals to exposed carbonate and evaporite sedimentary rocks. Besides a
detailed evaluation of the signal properties, we discuss implications
for SIF data sets and other remote sensing products.