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Spectral Signature of the Biosphere: NISTAR Finds It in Our Solar System From the Lagrangian L‐1 Point
Author(s) -
Carlson Barbara,
Lacis Andrew,
Colose Christopher,
Marshak Alexander,
Su Wenying,
Lorentz Steven
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl083736
Subject(s) - remote sensing , environmental science , shortwave , biosphere , climate model , exoplanet , meteorology , physics , planet , geology , radiative transfer , astronomy , climate change , oceanography , quantum mechanics
NISTAR, aboard the DSCOVR spacecraft, is one of the National Aeronautics and Space Administration's energy budget instruments designed to measure the seasonal changes in Earth's total outgoing radiation from a unique vantage point at the Lagrangian L‐1 point a million miles from Earth. Global radiation energy balance measurements are important constraints for climate models, but are difficult measurements to quantify. CERES data offer the best current observational constraints, but need extensive modeling to get global energy. NISTAR observes the entire dayside hemisphere of the Earth as a single pixel, splitting the shortwave radiation into broadband visible and near‐infrared components (analogous to the narrowband spectral ratios used to define vegetation indices). This spectral partitioning at the 0.7‐μm vegetation red edge offers unique constraints on climate model spectral treatment of cloud and surface albedos. Moreover, NISTAR's unique viewing geometry amounts to observing the Earth as an exoplanet, which opens a new perspective on exoplanet observations.