Estimation of biogenic volatile organic compound (BVOC) emissions in China using WRF–CLM–MEGAN coupled model

Yin, Longfei; Xu, Zhenying; Liu, Mingxu; Xu, Tingting; Wang, Tiantian; Liao, Wenling; Li, Mengmeng; Cai, Xiaoling; Kang, Ling; Zhang, Hongsheng; Yu, Shen

doi:10.5194/bg-2019-458

Cited by 4 publications

(6 citation statements)

References 28 publications

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“…These sensitivity simulations implied that moderate changes of PBL and NO x emissions could not explain the large north‐south discrepancies between simulated and observed isoprene concentrations found in this study. Therefore, the uncertainty in the isoprene emissions may contribute the most to the uncertainties in the isoprene simulation (L. Li et al., 2020; Yin et al., 2020).…”

Section: Experimental Methodologymentioning

confidence: 99%

“…Outside the US and Europe, this kind of comparison between simulated and measured isoprene mixing ratios is very rare, yet the uncertainty in isoprene emission can be even larger in many other regions of the world. Estimates of isoprene emissions in China, for example, span a wide range of 4–29 TgC yr −1 in previous studies (Chi & Xie, 2011; Fu & Liao, 2012; A. Guenther et al., 1995; Klinger et al., 2002; L. Y. Li & Xie, 2014; Li et al., 2013, 2020; Tie et al., 2006; Yin et al., 2020). It is under question whether lacking local EFs is an important reason for this large uncertainty, since field campaigns on emission flux measurements to develop isoprene EFs have mainly been carried out in the developed countries, as summarized in Lathière et al.…”

Section: Introductionmentioning

confidence: 94%

“…Guenther et al, 1995;Klinger et al, 2002;L. Y. Li & Xie, 2014;Li et al, 2013Li et al, , 2020Tie et al, 2006;Yin et al, 2020). It is under question whether lacking local EFs is an important reason for this large uncertainty, since field campaigns on emission flux measurements to develop isoprene EFs have mainly been carried out in the developed countries, as summarized in Lathière et al (2010), and very limited isoprene emission flux measurements have been conducted in China (Bai et al, 2003(Bai et al, , 2016(Bai et al, , 2017Geron et al, 2006;X.…”

Section: Introductionmentioning

confidence: 99%

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Isoprene Mixing Ratios Measured at Twenty Sites in China During 2012–2014: Comparison With Model Simulation

Zhang

et al. 2020

JGR Atmospheres

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Measurement-model comparisons for various atmospheric species have been widely used for evaluating the reliability of model simulations, yet such comparisons are quite limited for atmospheric isoprene due to the lack of systematic observations over a large scale. Here, we collected ambient air samples concurrently at 20 sites in China during 2012-2014 and compared the observed isoprene mixing ratios with those simulated by coupling MEGAN v2.1 with the 3-D Regional chEmical trAnsport Model. The observed average isoprene concentration for all 1,731 samples is 0.35 ± 0.03 ppbv, 13% higher than the model simulated average of 0.31 ± 0.02 ppbv; while during the growing season, the simulated average (0.53 ± 0.05 ppbv) is almost the same as the observed average (0.52 ± 0.04 ppbv). The observed isoprene average level in the north (0.35 ppbv) is similar to that in the south (0.37 ppbv). However, the model simulated average in the south (0.53 ppbv) is ∼4 times that in the north (0.14 ppbv). The model overestimated the observations at most southern sites but underestimated at most northern sites in the growing season, which might be resulted from inadequate characterization of isoprene-emitting land vegetation with fast afforestation in the north and rapid urbanization in the south. Compared to the model simulation, the observations revealed abnormally high isoprene levels in winter at some northern sites, largely due to nonbiogenic emissions, as evidenced by the enhancements of measured combustion tracers concurrent with the abnormally elevated isoprene levels. Plain Language Summary Isoprene alone accounts for approximately one-third of global emission of volatile organic compounds from both nature and human activities, yet in many parts of the world biogenic isoprene emission estimates have large uncertainties (reported isoprene emission estimates span 4-29 TgC y −1 in China), and narrowing these uncertainties is a challenging task. Here we collected ambient air samples concurrently at 20 sites over China during 2012-2014, and made measurementmodel comparison to check the emission estimates for isoprene, and found that although overall observed and predicted average isoprene levels matched well particularly during growing seasons, there exists a south-north discrepancy that model simulated averages in the south were much higher than the north while their observed averages were quite near each other. Modeled values overestimated at most southern sites but underestimated at most northern sites, probably the fast afforestation in the north and rapid urbanization in the southeast were inadequately characterized in the model. Abnormally higher isoprene levels were observed in winter at some northern sites probably due to contribution from nonbiogenic sources. Our results highlight that high-resolution PFT/LAI, field campaigns with higher spatial and temporal resolutions, as well as biomass burning activity data, are necessary for better observation-model comparison.

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Section: Experimental Methodologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

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Isoprene Mixing Ratios Measured at Twenty Sites in China During 2012–2014: Comparison With Model Simulation

Zhang

et al. 2020

JGR Atmospheres

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“…is an online coupled meteorology and chemistry model that can simulate meteorology fields and chemical species simultaneously (Grell et al, 2005;Fast et al, 2006). The MEGAN scheme is widely used for estimating biogenic emissions online with WRF-Chem (Jiang et al, 2012a;Wang et al, 2015;Abdi-Oskouei et al, 2018;Wei et al, 2018;Arghavani et al, 2019;Safronov et al, 2019;Visser et al, 2019;Li et al, 2020;Yin et al, 2020). The public versions (v4.2 and older) of WRF-Chem include the first MEGAN version (referred to as MEGANv1.0 hereafter) (Guenther et al, 1995) and the second version (referred to as MEGANv2.0 hereafter) (Guenther, 2006).…”

Section: Wrf-chem (Weather Research and Forecasting Model Coupled Witmentioning

confidence: 99%

Sensitivity of different BVOC emission schemes in WRF-Chem(v3.6) to vegetation distributions and its impacts over East China

Zhang

Zhao

Yang

et al. 2021

Preprint

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Abstract. Biogenic volatile organic compounds (BVOCs) simulated by current air quality and climate models still have large uncertainties, which can influence atmosphere chemistry and secondary pollutant formation over East China. These uncertainties are generally resulted from two sources. One is from different biogenic emission schemes coupled in model, representing for different treatments of physical and chemistry progresses during the emissions of BVOCs. The other is from the biased distribution of vegetation types over a specific region. In this study, the version of WRF-Chem updated by the University of Science and Technology of China (USTC version of WRF-Chem) from the public WRF-Chem(v3.6) is used. The modeling results over East China with different versions (v1.0, v2.0, v3.0) of Model of Emissions of Gases and Aerosols from Nature (MEGAN) in WRF-Chem are examined and documented. Sensitivity experiments with these three versions of MEGAN and two vegetation datasets are conducted to investigate the difference of three MEGAN versions in modeling biogenic VOCs and its dependence on the vegetation distributions. The experiments are also conducted for spring (April) and summer (July) to examine the seasonality of the modeling results. The results indicate that MEGANv3.0 simulates the largest amount of biogenic isoprene emissions over East China. The different performance among MEGAN versions is primarily due to their different treatments of applying emission factors and vegetation types. In particular, the results highlight the importance of considering sub-grid vegetation fraction in estimating BVOCs emissions. Among all activity factors, temperature-dependent factor dominates the seasonal change of activity factor in all three versions of MEGAN, while the different response to the leaf area index (LAI) change determines the difference among the three versions in seasonal variation of BVOC emissions. The simulated surface ozone concentration due to BVOCs can be significantly different among the experiments with three versions of MEGAN, which is mainly due to their impacts on surface VOCs and NOx concentrations. This study suggests that there is still large uncertain range in modeling BVOCs and their impacts on photochemistry and ozone production. More accurate vegetation distribution and measurements of biogenic emission flux and species concentration are needed to evaluate the model performance and reduce the uncertainties.

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“…WRF-Chem (Weather Research and Forecasting model coupled with Chemistry) is an online coupled meteorology and chemistry model that can simulate meteorology fields and chemical species simultaneously (Grell et al, 2005;Fast et al, 2006). The MEGAN scheme is widely used for estimating biogenic emissions online with WRF-Chem (Jiang et al, 2012a;Wang et al, 2015;Abdi-Oskouei et al, 2018;Wei et al, 2018;Arghavani et al, 2019;Safronov et al, 2019;Visser et al, 2019;Li et al, 2020;Yin et al, 2020). The public versions (v4.2 and older) of WRF-Chem include the first MEGAN version (referred to as MEGAN v1.0 hereafter) (Guenther et al, 1995) and the second version (referred to as MEGAN v2.0 hereafter) (Guenther et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Modeling sensitivities of BVOCs to different versions of MEGAN emission schemes in WRF-Chem (v3.6) and its impacts over eastern China

et al. 2021

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Abstract. Biogenic volatile organic compounds (BVOCs) simulated by current air quality and climate models still have large uncertainties, which can influence atmospheric chemistry and secondary pollutant formation. These modeling sensitivities are primarily due to two sources. One originates from different treatments in the physical and chemical processes associated with the emission rates of BVOCs. The other is errors in the specification of vegetation types and their distribution over a specific region. In this study, the version of the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) updated by the University of Science and Technology of China (USTC version of WRF-Chem) from the public WRF-Chem(v3.6) is used. The modeling results over eastern China with different versions (v1.0, v2.0, v3.0) of the Model of Emissions of Gases and Aerosols from Nature (MEGAN) in WRF-Chem are examined or documented. Sensitivity experiments with these three versions of MEGAN and two vegetation datasets are conducted to investigate the difference of three MEGAN versions in modeling BVOCs and its dependence on the vegetation distributions. The experiments are also conducted for spring (April) and summer (July) to examine the seasonality of the modeling results. The results indicate that MEGAN v3.0 simulates the largest amount of biogenic isoprene emissions over eastern China. The different performance among MEGAN versions is primarily due to their different treatments of applying emission factors and vegetation types. In particular, the results highlight the importance of considering the sub-grid vegetation fraction in estimating BVOC emissions over eastern China, which has a large area of urbanization. Among all activity factors, the temperature-dependent factor dominates the seasonal change of activity factor in all three versions of MEGAN, while the different response to the leaf area index (LAI) change determines the difference among the three versions in seasonal variation of BVOC emissions. The simulated surface ozone concentration due to BVOCs can be significantly different (ranging from 1 to more than 10 ppbv in some regions) among the experiments with three versions of MEGAN, which is mainly due to their impacts on surface VOCs and NOx concentrations. Theoretically MEGAN v3.0 that is coupled with the land surface scheme and considers the sub-grid vegetation effect should overcome previous versions of MEGAN in WRF-Chem. However, considering uncertainties of retrievals and anthropogenic emissions over eastern China, it is still difficult to apply satellite retrievals of formaldehyde and/or limited sparse in situ observations to constrain the uncertain parameters or functions in BVOC emission schemes and their impacts on photochemistry and ozone production. More accurate vegetation distribution and measurements of biogenic emission fluxes and species concentrations are still needed to better evaluate and optimize models.

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Estimation of biogenic volatile organic compound (BVOC) emissions in China using WRF–CLM–MEGAN coupled model

Cited by 4 publications

References 28 publications

Isoprene Mixing Ratios Measured at Twenty Sites in China During 2012–2014: Comparison With Model Simulation

Isoprene Mixing Ratios Measured at Twenty Sites in China During 2012–2014: Comparison With Model Simulation

Sensitivity of different BVOC emission schemes in WRF-Chem(v3.6) to vegetation distributions and its impacts over East China

Modeling sensitivities of BVOCs to different versions of MEGAN emission schemes in WRF-Chem (v3.6) and its impacts over eastern China

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