Analysis of CO.sub.2 spatio-temporal variations in China using a weather-biosphere online coupled model.

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Date: May 12, 2021
From: Atmospheric Chemistry and Physics(Vol. 21, Issue 9)
Publisher: Copernicus GmbH
Document Type: Brief article
Length: 316 words

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Abstract :

The dynamics of atmospheric CO.sub.2 has received considerable attention in the literature, yet significant uncertainties remain within the estimates of contribution from the terrestrial flux and the influence of atmospheric mixing. In this study we apply the WRF-Chem model configured with the Vegetation Photosynthesis and Respiration Model (VPRM) option for biomass fluxes in China to characterize the dynamics of CO.sub.2 in the atmosphere. The online coupled WRF-Chem model is able to simulate biosphere processes (photosynthetic uptake and ecosystem respiration) and meteorology in one coordinate system. We apply WRF-Chem for a multi-year simulation (2016-2018) with integrated data from a satellite product, flask samplings, and tower measurements to diagnose the spatio-temporal variations of CO.sub.2 fluxes and concentrations in China. We find that the spatial distribution of CO.sub.2 was dominated by anthropogenic emissions, while its seasonality (with maxima in April 15 ppmv higher than minima in August) was dominated by the terrestrial flux and background CO.sub.2 . Observations and simulations revealed a consistent increasing trend in column-averaged CO.sub.2 (XCO.sub.2) of 2.46 ppmv (0.6 % yr.sup.-1) resulting from anthropogenic emission growth and biosphere uptake. WRF-Chem successfully reproduced ground-based measurements of surface CO.sub.2 concentration with a mean bias of -0.79 ppmv and satellite-derived XCO.sub.2 with a mean bias of 0.76 ppmv. The model-simulated seasonality was also consistent with observations, with correlation coefficients of 0.90 and 0.89 for ground-based measurements and satellite data, respectively. Tower observations from a background site at Lin'an (30.30.sup." N, 119.75.sup." E) revealed a strong correlation (-0.98) between vertical CO.sub.2 and temperature gradients, suggesting a significant influence of boundary layer thermal structure on the accumulation and depletion of atmospheric CO.sub.2.

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Gale Document Number: GALE|A661566911