Potential improvements in global carbon flux estimates from a network of laser heterodyne radiometer measurements of column carbon dioxide

Abstract

Abstract. We present observing system simulation experiments (OSSEs) to evaluate the impact of a proposed network of ground-based miniaturized laser heterodyne radiometer (mini-LHR) instruments that measure atmospheric column-averaged carbon dioxide (XCO2) with a 1 ppm precision. A particular strength of this passive measurement approach is its insensitivity to clouds and aerosols due to its direct sun pointing and narrow field of view (0.2∘). Developed at the NASA Goddard Space Flight Center (GSFC), these portable, low-cost mini-LHR instruments were designed to operate in tandem with the sun photometers used by the AErosol RObotic NETwork (AERONET). This partnership allows us to leverage the existing framework of AERONET's global ground network of more than 500 sites as well as providing simultaneous measurements of aerosols that are known to be a major source of error in retrievals of XCO2 from passive nadir-viewing satellite observations. We show, using the global 3-D GEOS-Chem chemistry transport model, that a deployment of 50 mini-LHRs at strategic (but not optimized) AERONET sites significantly improves our knowledge of global and regional land-based CO2 fluxes. This improvement varies seasonally and ranges 58 %–81 % over southern lands, 47 %–76 % over tropical lands, 71 %–92 % over northern lands, and 64 %–91 % globally. We also show significant added value from combining mini-LHR instruments with the existing ground-based NOAA flask network. Collectively, these data result in improved a posteriori CO2 flux estimates on spatial scales of ∼10 km2, especially over North America and Europe, where the ground-based networks are densest. Our studies suggest that the mini-LHR network could also play a substantive role in reducing carbon flux uncertainty in Arctic and tropical systems by filling in geographical gaps in measurements left by ground-based networks and space-based observations. A realized network would also provide necessary data for the quinquennial global stocktakes that form part of the Paris Agreement.

Economic Growth Determinants in New and Old Eu Countries With Focus on Construction

“…By 2020, countries submit their plans for climate action and CO 2 reduction known as nationally determined contributions (NDCs). Since the Agreement, subsequent COPs have reviewed implementation progress across its signatories (Palmer et al, 2019). This is especially important given the aggregate of the NDCs are predicted to underperform against the Agreement's target.…”

A new space-borne perspective of crop productivity variations over the US Corn Belt

“…We compare the SIF data with a posteriori CO 2 surface fluxes within the region of interest (ROI) that were inferred from the GOSAT XCO 2 v7.1 product from the University of Leicester (Buchwitz et al, 2018) using the GEOS-Chem atmospheric transport model and an ensemble Kalman filter (Feng et al, 2016;Palmer et al, 2019). In the inversion, we use the v9.02 GEOS-Chem global chemistry transport model (http:// acmg.seas.harvard.edu/geos/index.html) to relate a priori surface fluxes (and their uncertainty) to atmospheric CO2 observations.…”

“…We then infer posterior fluxes by optimally fitting the model simulations with GOSAT XCO 2 retrievals (Feng et al, 2009). For further information on our inversion setup, the reader is referred to Feng et al (2016) and Palmer et al (2019).…”

Statistical Characterization of Temperature and Pressure Vertical Profiles for the Analysis of Laser Heterodyne Radiometry Data

“…A recent derivative of the OEM method that has been presented for LHR data processing makes use of the Planetary Spectrum Generator (PSG) API to extract Modern Era Retrospective Analysis, Version 2 (MERRA-2) vertical profiles a priori for the spectral fitting routine [9]. Spectral simulations using pressure, temperature, and volume mixing ratios from MERRA-2 are used to calculate spectra by fitting CO 2 abundances using the OEM.…”

“…A limitation of this database is that data availability is limited by a lag of several days up to one month for certain products. Palmer et al use the M2I3NVASM component, which does not update daily, severely hindering the capability for near-real time data analysis [9].…”