Abstract: At present，the mainstream of global carbon flux monitoring is realized through assimilation algorithms by integrating ground-based greenhouse gas flux network and concentration measurement，satellite-based remote sensing greenhouse gas concentration and other data sources.Considering the limited coverage of in-situ measurement，a direct carbon flux measurement method was proposed.The method was based on the first order closure theory of turbulence，adopted the horizontal wind profile and CO₂ concentration profile and combined with Monin-Obukhov similarity theory to directly calculate CO₂ flux.The horizontal wind profile was retrieved by the dual looking lidar using the coherent Doppler wind measurement method，and the CO₂ concentration profile was detected based on the differential absorption principle of the lidar.The method could achieve the current international wind measurement accuracy of 1m/s and the detection accuracy of 10^-6 CO₂ concentration based on the satellite platform.Through preliminary analysis of the flux model，it is found that under neutral atmospheric condition with strong carbon sources（such as near ground CO₂ concentration difference>10^-5），the accuracy of the CO₂ flux can meet the requirements of scientific application，that is，the uncertainty of CO2 flux measurement within 25% can be achieved.In general，this method can provide large-scale CO₂ flux observation data as a meaningful supplement to the in-situ measurement of ground-based carbon flux.

Key words: carbon flux measurement, Monin-Obukhov similarity theory, satellite-based remote sensing, turbulence closure theory, Doppler coherent wind measurement