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On the Ability of Space‐Based Passive and Active Remote Sensing Observations of CO 2 to Detect Flux Perturbations to the Carbon Cycle
Author(s) -
Crowell Sean M. R.,
Randolph Kawa S.,
Browell Edward V.,
Hammerling Dorit M.,
Moore Berrien,
Schaefer Kevin,
Doney Scott C.
Publication year - 2018
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2017jd027836
Subject(s) - environmental science , latitude , atmospheric sciences , biosphere , flux (metallurgy) , carbon cycle , annual cycle , carbon flux , sciamachy , greenhouse gas , climatology , remote sensing , meteorology , troposphere , geography , geology , physics , geodesy , ecology , oceanography , materials science , astronomy , ecosystem , metallurgy , biology
Space‐borne observations of CO 2 are vital to gaining understanding of the carbon cycle in regions of the world that are difficult to measure directly, such as the tropical terrestrial biosphere, the high northern and southern latitudes, and in developing nations such as China. Measurements from passive instruments such as GOSAT and OCO‐2, however, are constrained by solar zenith angle limitations as well as sensitivity to the presence of clouds and aerosols. Active measurements such as those in development for the Active Sensing of CO 2 Emissions over Nights, Days and Seasons (ASCENDS) mission show strong potential for making measurements in the high‐latitude winter and in cloudy regions. In this work we examine the enhanced flux constraint provided by the improved coverage from an active measurement such as ASCENDS. The simulation studies presented here show that with sufficient precision, ASCENDS will detect permafrost thaw and fossil fuel emissions shifts at annual and seasonal time scales, even in the presence of transport errors, representativeness errors, and biogenic flux errors. While OCO‐2 can detect some of these perturbations at the annual scale, the seasonal sampling provided by ASCENDS provides the stronger constraint.