Kengo Sudo’s research while affiliated with Nagoya University and other places

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Publications (29)


Annual mean HCHO columns (×1016 molec. cm-2) in 2019 and 2020 obtained from TROPOMI retrievals (first column) and a standard CHASER simulation (second column). The differences between the model and observations in the respective years are shown in the third column. The unit of difference is × 1015 molec. cm-2.
Seasonal variation in HCHO columns (×1016 molec. cm-2) in (a) eastern China (E-China; 30–40° N, 110–123° E), (b) the eastern United States (E-USA; 32–43° N, 95–71° W), (c) the western United States (W-USA; 32–43° N, 125–100° W), (d) Europe (35–60° N, -10° W–30° E), (e) central Africa (C-Africa; 4° S–5° N, 10–40° E), (f) northern Africa (N-Africa; 5–15° N, 10° W–30° E), (g) southern Africa (S-Africa; 5–15° S, 10–30° E), (h) South America (S-America; 20° S–0° N, 50–70° W), (i) India (7.5–35° N, 68–89° E), (j) the Indo-Gangetic Plain (IGP; 21–33° N, 72–89° E), (k) east India (E-India; 15–25° N, 80–90° E), (l) south India (S-India; 0–15° N, 63–80° E), (m) Southeast Asia (SE-Asia, 10–20° N, 96–105° E), and (n) the remote Pacific region (28° S–32° N, 117–177° W), as inferred from CHASER simulations (blue) and TROPOMI observations (red). Blue numbers denote MBE between the TROPOMI and CHASER HCHO columns. The observed and simulated mean values represent the average of 2019 and 2020.
Two-year (2019 and 2020) mean CHASER (first column) and TROPOMI (second column) HCHO columns (×1016 molec. cm-2 cm-2) in China (18.19–53.45° N, 73.67–135.02° E), the United States (18.91–45° N, 66–171° W), Indonesia (10° S–6° N, 95–142° E), and Brazil (33° S–5.24° N, 34–73° W). The differences between the datasets are presented in the third column. Only the coincident dates among the datasets are used to calculate the annual mean data.
Seasonal variation of HCHO (× 1016 molec. cm-2) in selected regions, as inferred from standard simulations (blue), TROPOMI observations (red), and ANI estimates (green). Anthropogenic VOC emissions are increased 3-fold in the ANI simulations. The blue numbers denote the MBE between the TROPOMI and CHASER HCHO columns. The MBE between the ANI and TROPOMI columns is shown in green. The coordinate bounds of the regions are similar to those used in Fig. 2. Simulations and observations in 2019 were used to calculate the monthly mean values.
Annual mean HCHO columns (×1016 molec. cm-2) in 2019, obtained from the (a) standard and (b) OLNE simulations. The HTAP-2008 NOx emission inventory was used instead of the HTAP-2018 inventory for the OLNE simulations (Table 1). The remaining emission inventories were similar in both simulations. (c) Global relative differences between the two HCHO simulations (OLNE-Standard). (d) Relative differences (global) between two OH (OLNE-Standard) simulations. The standard and OLNE OH simulation settings are similar to those described for Table 1. The OH and HCHO simulations were obtained simultaneously.

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Evaluating CHASER V4.0 global formaldehyde (HCHO) simulations using satellite, aircraft, and ground-based remote-sensing observations
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July 2024

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Kengo Sudo

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Hitoshi Irie

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Formaldehyde (HCHO), a precursor to tropospheric ozone, is an important tracer of volatile organic compounds (VOCs) in the atmosphere. Two years (2019–2020) of HCHO simulations obtained from the global chemistry transport model CHASER at a horizontal resolution of 2.8° × 2.8° have been evaluated using the Tropospheric Monitoring Instrument (TROPOMI) and multi-axis differential optical absorption spectroscopy (MAX-DOAS) observations. In situ measurements from the Atmospheric Tomography Mission (ATom) in 2018 were used to evaluate the HCHO simulations for 2018. CHASER reproduced the TROPOMI-observed global HCHO spatial distribution with a spatial correlation (r) of 0.93 and a negative bias of 7 %. The model showed a good capability to reproduce the observed magnitude of the HCHO seasonality in different regions, including the background conditions. The discrepancies between the model and satellite in the Asian regions were related mainly to the underestimated and missing anthropogenic emission inventories. The maximum difference between two HCHO simulations based on two different nitrogen oxide (NOx) emission inventories was 20 %. TROPOMI's finer spatial resolution than that of the Ozone Monitoring Instrument (OMI) sensor reduced the global model–satellite root-mean-square error (RMSE) by 20 %. The OMI- and TROPOMI-observed seasonal variations in HCHO abundances were consistent. The simulated seasonality showed better agreement with TROPOMI in most regions. The simulated HCHO and isoprene profiles correlated strongly (R=0.81) with the ATom observations. However, CHASER overestimated HCHO mixing ratios over dense vegetation areas in South America and the remote Pacific region (background condition), mainly within the planetary boundary layer (< 2 km). The simulated seasonal variations in the HCHO columns showed good agreement (R>0.70) with the MAX-DOAS observations and agreed within the 1σ standard deviation of the observed values. However, the temporal correlation (R∼0.40) was moderate on a daily scale. CHASER underestimated the HCHO levels at all sites, and the peak occurrences in the observed and simulated HCHO seasonality differed. The coarseness of the model's resolution could potentially lead to such discrepancies. Sensitivity studies showed that anthropogenic emissions were the highest contributor (up to ∼ 35 %) to the wintertime regional HCHO levels.

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Evaluating CHASER V.40 global formaldehyde (HCHO) simulations using satellite, aircraft, and ground-based remote sensing observations

November 2023

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50 Reads

Formaldehyde (HCHO), a precursor to tropospheric ozone, is an important tracer of volatile organic compounds (VOCs) in the atmosphere. Two years of HCHO simulations obtained from the global chemistry transport model CHASER at horizontal resolution of 2.8° × 2.8° have been evaluated using observations from the Tropospheric Ozone Monitoring Experiment (TROPOMI), Atmospheric Tomography Mission (ATom), and multi-axis differential optical absorption spectroscopy (MAX-DOAS) observations. CHASER reproduced the observed global HCHO spatial distribution with spatial correlation (r) of 0.93 and negative bias of 7%. The model showed good capability for reproducing the observed magnitude of the HCHO seasonality in different regions, including the background conditions. The discrepancies between the model and satellite in the Asian regions were related mainly to the underestimated and missing anthropogenic emission inventories. TROPOMI’s finer spatial resolution than that of the Ozone monitoring Experiment (OMI) sensor reduced the global model–satellite root-mean-square-error (RMSE) by 20%. The OMI and TROPOMI observed seasonal variations in HCHO abundances were consistent. However, the simulated seasonality showed better agreement with TROPOMI in most regions. The simulated HCHO and isoprene profiles correlated (R = 0.81) strongly with the ATom observations. CHASER overestimated HCHO mixing ratios over dense vegetation areas in South America and the remote Pacific (background condition) regions, mainly within the planetary boundary layer (<2 km). The simulated temporal (daily and diurnal) variations in the HCHO mixing ratio showed good congruence with the MAX-DOAS observations and agreed within the 1-sigma standard deviation of the observed values.


Historical (1960–2014) lightning and LNOx trends and their controlling factors in a chemistry–climate model

October 2023

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62 Reads

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1 Citation

Lightning can cause natural hazards that result in human and animal injuries and fatalities, infrastructure destruction, and wildfire ignition. Lightning-produced NOx (LNOx), a major NOx (NOx=NO+NO2) source, plays a vital role in atmospheric chemistry and global climate. The Earth has experienced marked global warming and changes in aerosol and aerosol precursor emissions (AeroPEs) since the 1960s. Investigating long-term historical (1960–2014) lightning and LNOx trends can provide important indicators for all lightning-related phenomena and for LNOx effects on atmospheric chemistry and global climate. Understanding how global warming and changes in AeroPEs influence historical lightning and LNOx trends can be helpful in providing a scientific basis for assessing future lightning and LNOx trends. Moreover, global lightning activities' responses to large volcanic eruptions such as the 1991 Pinatubo eruption are not well elucidated and are worth exploring. This study employed the widely used cloud top height lightning scheme (CTH scheme) and the newly developed ice-based ECMWF-McCAUL lightning scheme to investigate historical (1960–2014) lightning and LNOx trends and variations as well as their influencing factors (global warming, increases in AeroPEs, and the Pinatubo eruption) in the framework of the CHASER (MIROC) chemistry–climate model. The results of the sensitivity experiments indicate that both lightning schemes simulated almost flat global mean lightning flash rate anomaly trends during 1960–2014 in CHASER (the Mann–Kendall trend test (significance inferred as 5 %) shows no trend for the ECMWF-McCAUL scheme, but a 0.03 %yr-1 significant increasing trend is detected for the CTH scheme). Moreover, both lightning schemes suggest that past global warming enhances historical trends for global mean lightning density and global LNOx emissions in a positive direction (around 0.03 %yr-1 or 3 %K-1). However, past increases in AeroPEs exert an opposite effect on the lightning and LNOx trends (-0.07 % to -0.04 %yr-1 for lightning and -0.08 % to -0.03 %yr-1 for LNOx) when one considers only the aerosol radiative effects in the cumulus convection scheme. Additionally, effects of past global warming and increases in AeroPEs in lightning trends were found to be heterogeneous across different regions when analyzing lightning trends on the global map. Lastly, this paper is the first of study results suggesting that global lightning activities were markedly suppressed during the first year after the Pinatubo eruption as shown in both lightning schemes (global lightning activities decreased by as much as 18.10 % as simulated by the ECMWF-McCAUL scheme). Based on the simulated suppressed lightning activities after the Pinatubo eruption, the findings also indicate that global LNOx emissions decreased after the 2- to 3-year Pinatubo eruption (1.99 %–8.47 % for the annual percentage reduction). Model intercomparisons of lightning flash rate trends and variations between our study (CHASER) and other Coupled Model Intercomparison Project Phase 6 (CMIP6) models indicate great uncertainties in historical (1960–2014) global lightning trend simulations. Such uncertainties must be investigated further.


Figure 1: Annual mean lightning flash densities from (a) LIS/OTD satellite observations spanning 1996-2000, (b) the STD 286
Figure 2: Lightning flash rate anomalies of 1996-2013 within ±41.25° latitude obtained from two numerical experiments (STD-F1 291
Figure 3: Monthly time-series data of global mean surface temperature anomalies with 1-D Gaussian (Denoising) Filter applied 329
Figure 8: Time-series data of 1960-2014 annual global LNOx production anomalies (TgN yr -1 ) and their fitting curves simulated 422
Figure 14: Comparisons of simulated global mean lightning flash rate anomalies found in our study (CHASER) and other CMIP6 574
Historical (1960–2014) lightning and LNO x trends and their controlling factors in a chemistry–climate model

April 2023

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85 Reads

Lightning can cause natural disasters that engender human and animal injuries or fatalities, infrastructure destruction, and wildfire ignition. Lightning-produced NOx (LNOx), a major NOx (NOx = NO + NO2) source, plays a vital role in atmospheric chemistry and global climate. The Earth has experienced marked global warming and changes in aerosol and aerosol precursor emissions (AeroPEs) since the 1960s. Investigating long-term historical (1960–2014) lightning and LNOx trends can provide important indicators for all lightning-related phenomena and for LNOx effects on atmospheric chemistry and global climate. Understanding how global warming and changes in AeroPEs influence historical lightning–LNOx trends is also helpful because it can provide a scientific basis for assessing future lightning–LNOx trends. Moreover, global lightning activities’ responses to large volcanic eruptions (such as the 1991 Pinatubo eruption) are not well elucidated, and are worth exploring. This study used the widely used cloud top height lightning scheme (CTH scheme) and the newly developed ice-based ECMWF-McCAUL lightning scheme to investigate historical (1960–2014) lightning–LNOx trends and variations and their controlling factors (global warming, increases in AeroPEs, and Pinatubo eruption) in the framework of the CHASER (MIROC) chemistry–climate model. Results of sensitive experiments indicate that both lightning schemes simulated almost flat global mean lightning flash rate trends during 1960–2014 in CHASER. Moreover, both lightning schemes suggest that past global warming enhances historical trends of global mean lightning density and global LNOx emissions in a positive direction (around 0.03 % yr−1 or 3 % K−1). However, past increases in AeroPEs exert an opposite effect to the lightning–LNOx trends (−0.07 % yr−1 – −0.04 % yr−1 for lightning and −0.08 % yr–1 – −0.03 % yr–1 for LNOx). Additionally, effects of past global warming and increases in AeroPEs on lightning trends were found to be heterogeneous across different regions when analyzing lightning trends on the global map. Lastly, this study is the first to suggest that global lightning activities were suppressed markedly during the first year after the Pinatubo eruption shown in both lightning schemes (global lightning activities decreased by as much as 17.02 % simulated by the ECMWF-McCAUL scheme). Based on the simulated suppressed lightning activities after the Pinatubo eruption, our study also indicates that global LNOx emissions decreased after the Pinatubo eruption (2.41 % – 8.72 % for the annual percentage reduction), which lasted 2–3 years. Model intercomparisons of lightning flash rate trends and variations between our study (CHASER) and other Coupled Model Intercomparison Project Phase 6 (CMIP6) models indicate significant uncertainties in historical (1960–2014) global lightning trend simulations. Such uncertainties must be investigated further.


Multi-axis differential optical absorption spectroscopy (MAX-DOAS) observations of formaldehyde and nitrogen dioxide at three sites in Asia and comparison with the global chemistry transport model CHASER

September 2022

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100 Reads

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6 Citations

Formaldehyde (HCHO) and nitrogen dioxide (NO2) concentrations and profiles were retrieved from ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) observations during January 2017–December 2018 at three sites in Asia: (1) Phimai (15.18∘ N, 102.5∘ E), Thailand; (2) Pantnagar (29∘ N, 78.90∘ E) in the Indo-Gangetic Plain (IGP), India; and (3) Chiba (35.62∘ N, 140.10∘ E), Japan. Retrievals were performed using the Japanese MAX-DOAS profile retrieval algorithm ver. 2 (JM2). The observations were used to evaluate the NO2 and HCHO partial columns and profiles (0–4 km) simulated using the global chemistry transport model (CTM) CHASER (Chemical Atmospheric General Circulation Model for Study of Atmospheric Environment and Radiative Forcing). The NO2 and HCHO concentrations at all three sites showed consistent seasonal variation throughout the investigated period. Biomass burning affected the HCHO and NO2 variations at Phimai during the dry season and at Pantnagar during spring (March–May) and post-monsoon (September–November). Results found for the HCHO-to-NO2 ratio (RFN), an indicator of high ozone sensitivity, indicate that the transition region (i.e., 1 < RFN < 2) changes regionally, echoing the recent finding for RFN effectiveness. Moreover, reasonable estimates of transition regions can be derived, accounting for the NO2–HCHO chemical feedback. The model was evaluated against global NO2 and HCHO columns data retrieved from Ozone Monitoring Instrument (OMI) observations before comparison with ground-based datasets. Despite underestimation, the model well simulated the satellite-observed global spatial distribution of NO2 and HCHO, with respective spatial correlations (r) of 0.73 and 0.74. CHASER demonstrated good performance, reproducing the MAX-DOAS-retrieved HCHO and NO2 abundances at Phimai, mainly above 500 m from the surface. Model results agree with the measured variations within the 1-sigma (1σ) standard deviation of the observations. Simulations at higher resolution improved the modeled NO2 estimates for Chiba, reducing the mean bias error (MBE) for the 0–2 km height by 35 %, but resolution-based improvements were limited to surface layers. Sensitivity studies show that at Phimai, pyrogenic emissions contribute up to 50 % and 35 % to HCHO and NO2 concentrations, respectively.


Introducing new lightning schemes into the CHASER (MIROC) chemistry–climate model

July 2022

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68 Reads

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7 Citations

The formation of nitrogen oxides (NOx) associated with lightning activities (hereinafter designated as LNOx) is a major source of NOx. In fact, it is regarded as the dominant NOx source in the middle to upper troposphere. Therefore, improving the prediction accuracy of lightning and LNOx in chemical climate models is crucially important. This study implemented three new lightning schemes with the CHASER (MIROC) global chemical transport and climate model. The first lightning scheme is based on upward cloud ice flux (ICEFLUX scheme). The second one (the original ECMWF scheme), also adopted in the European Centre for Medium-Range Weather Forecasts (ECMWF) forecasting system, calculates lightning flash rates as a function of QR (a quantity intended to represent the charging rate of collisions between graupel and other types of hydrometeors inside the charge separation region), convective available potential energy (CAPE), and convective cloud-base height. For the original ECMWF scheme, by tuning the equations and adjustment factors for land and ocean, a new lightning scheme called the ECMWF-McCAUL scheme was also tested in CHASER. The ECMWF-McCAUL scheme calculates lightning flash rates as a function of CAPE and column precipitating ice. In the original version of CHASER (MIROC), lightning is initially parameterized with the widely used cloud-top height scheme (CTH scheme). Model evaluations with lightning observations conducted using the Lightning Imaging Sensor (LIS) and Optical Transient Detector (OTD) indicate that both the ICEFLUX and ECMWF schemes simulate the spatial distribution of lightning more accurately on a global scale than the CTH scheme does. The ECMWF-McCAUL scheme showed the highest prediction accuracy for the global distribution of lightning. Evaluation by atmospheric tomography (ATom) aircraft observations (NO) and tropospheric monitoring instrument (TROPOMI) satellite observations (NO2) shows that the newly implemented lightning schemes partially facilitated the reduction of model biases (NO and NO2), typically within the regions where LNOx is the major source of NOx, when compared to using the CTH scheme. Although the newly implemented lightning schemes have a minor effect on the tropospheric mean oxidation capacity compared to the CTH scheme, they led to marked changes in oxidation capacity in different regions of the troposphere. Historical trend analyses of flash and surface temperatures predicted using CHASER (2001–2020) show that lightning schemes predicted increasing trends of lightning or no significant trends, except for one case of the ICEFLUX scheme, which predicted a decreasing trend of lightning. The global lightning rates of increase during 2001–2020 predicted by the CTH scheme were 17.69 % ∘C-1 and 2.50 % ∘C-1, respectively, with and without meteorological nudging. The un-nudged runs also included the short-term surface warming but without the application of meteorological nudging. Furthermore, the ECMWF schemes predicted a larger increasing trend of lightning flash rates under the short-term surface warming by a factor of 4 (ECMWF-McCAUL scheme) and 5 (original ECMWF scheme) compared to the CTH scheme without nudging. In conclusion, the three new lightning schemes improved global lightning prediction in the CHASER model. However, further research is needed to assess the reproducibility of trends of lightning over longer periods.


MAX-DOAS observations of formaldehyde and nitrogen dioxide at three sites in Asia and comparison with the global chemistry transport model CHASER

March 2022

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47 Reads

Formaldehyde (HCHO) and nitrogen dioxide (NO2) concentrations and profiles were retrieved from ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) observations during January 2017 through December 2018 at three sites in Asia: (1) Phimai (15.18° N, 102.5° E), Thailand; (2) Pantnagar (29° N, 78.90° E) in the Indo Gangetic plain (IGP), India; and (3) Chiba (35.62° N, 140.10° E), Japan. The observations were used to evaluate the NO2 and HCHO partial columns and profiles (0–4 km) simulated using the global chemistry transport model (CTM) CHASER. The NO2 and HCHO concentrations at all three sites showed consistent seasonal variations throughout the investigated period. Biomass burning affected the HCHO and NO2 variation in Phimai during the dry season and in Pantnagar during spring (March–May) and post-monsoon (September–November). The results on the HCHO to NO2 ratio (RFN), an indicator of high ozone sensitivity, show that the transition region (i.e., 1


Introducing new lightning schemes into the CHASER (MIROC) chemistry climate model

March 2022

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21 Reads

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2 Citations

The formation of nitrogen oxides (NOx) associated with lightning activities (hereinafter designated as LNOx) is a major source of NOx. In fact, it is regarded as the most dominant NOx source in the upper troposphere. Therefore, improve the prediction accuracy of lightning and LNOx in chemical climate models is crucially important. This study implemented two new lightning schemes with the CHASER (MIROC) global chemical transport/climate model. The first lightning scheme is based on upward cloud ice flux (ICEFLUX scheme), whereas the second, also adopted in the European Centre for Medium-Range Weather Forecasts (ECMWF) forecasting system (original ECMWF scheme). In the case of the original ECMWF scheme, by tuning the equations and adjustment factors for land and ocean, a modified ECMWF scheme was also tested in CHASER. In the original version of CHASER (MIROC), lightning is initially parameterized with the widely used cloud top height scheme (CTH scheme). Model evaluations with lightning observations conducted using an optical transient detector (OTD) indicate that both the ICEFLUX and ECMWF schemes simulate the spatial distribution of lightning more accurately on a global scale than the CTH scheme does. The modified ECMWF scheme showed the highest prediction accuracy for the global distribution of lightning. Validation by atmospheric tomography (ATom) aircraft observations and tropospheric monitoring instrument (TROPOMI) satellite observations shows that the ICEFLUX scheme reduced the model biases to a greater extent than the ECMWF schemes when compared using the CTH scheme. The effects of the newly introduced lightning schemes on the tropospheric chemical fields were evaluated by comparison with the CTH scheme. Although the newly implemented lightning schemes have a minor effect on the tropospheric mean oxidation capacity compared to the CTH scheme, they led to marked change of oxidation capacity in different regions of the troposphere. Long-term trend analyses of flash and surface temperatures predicted using CHASER (2001–2020) show that lightning schemes predicted an increasing trend of lightning, except for the ICEFLUX scheme, which predicted a decreasing trend of lightning. The global lightning rates of increase during 2001–2020 predicted by the CTH scheme were 17.86 %/°C and 2.60 %/°C, respectively, with and without nudging, which are slightly beyond the range of an earlier study (5 %/°C–16 %/°C). Furthermore, the ECMWF schemes predicted a larger increasing trend of lightning flash rates under global warming by a factor of 3 (modified ECMWF scheme) and 5 (original ECMWF scheme) compared to the CTH scheme without nudging. In conclusion, the two new lightning schemes improved global lightning prediction in the CHASER model. However, further research is needed to assess the reproductivity of long-term trends of lightning.


MAX-DOAS observations of formaldehyde and nitrogen dioxide at three sites in Asia and comparison with the global chemistry transport model CHASER

October 2021

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85 Reads

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1 Citation

Formaldehyde (HCHO) and nitrogen dioxide (NO2) concentrations and profiles were retrieved from ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) observation during January 2017 through December 2018 at three sites in Asia: (1) Phimai in Thailand (15.18° N, 102.5° E); (2) Pantnagar (29° N, 78.90° E) in the Indo Gangetic plain (IGP) in India; and (3) Chiba (35.62° N, 140.10° E) in Japan. The NO2 and HCHO partial columns (< 4 km) and profiles simulated using the global chemistry transport model (CTM) and CHASER were compared to those of MAX-DOAS. The vertical sensitivity of the datasets was elucidated using the averaging kernel (AK) information from the MAX-DOAS retrievals. The NO2 and HCHO concentrations at all three sites showed consistent seasonal variation throughout the investigated period. Biomass burning affected the HCHO and NO2 variation in Phimai during the dry season and in Pantnagar during spring (March–May) and the post-monsoon (September–November) season. High NO2 concentrations in Phimai during the wet season (June–September) are attributed to soil emissions of nitrogen oxides (NOx), confirmed from satellite observations and CHASER simulations. Comparison with CHASER shows that the seasonal variations in the HCHO and NO2 abundances at Phimai and Chiba agree well, with a correlation coefficient (R) of 0.80. Results agree with the variation, ranging mainly within the one sigma standard deviation of the observations. At Phimai, pyrogenic emissions contribute to the HCHO and NO2 concentrations up to ~50 and ~35 %, respectively. CHASER showed limited skills in reproducing the NO2 and HCHO variability at Pantnagar. However, the CHASER simulations in the IGP region agreed well with the reported results. Sensitivity studies showed that anthropogenic emissions affected the seasonal variation of NO2 and HCHO concentrations in the IGP region.


Citations (20)


... However, these studies utilized trend lines because of the significant interannual variability in the lightning parameters, so the apparent differences may be muted if we employed the same trend analysis. Further, while there are regions with increasing and decreasing lightning, the mean global change in lightning over this time period is zero, consistent with other studies (e.g., He and Sudo, 2023). ...

Reference:

A new lightning scheme in the Canadian Atmospheric Model (CanAM5.1): implementation, evaluation, and projections of lightning and fire in future climates
Historical (1960–2014) lightning and LNOx trends and their controlling factors in a chemistry–climate model

... The spatial distributions of formaldehyde-to-NO 2 ratios (FNR), which are typically used to indicate NO x levels, and NO 2 concentrations are shown in Figure S13 in Supporting Information S1. A FNR less than 1 represents a VOC-limited (or NO x -rich) condition (Duncan et al., 2010;Hoque et al., 2022). Figure S14 in Supporting Information S1 shows time series of the observed and simulated NO 2 concentrations along with statistical summaries. ...

Multi-axis differential optical absorption spectroscopy (MAX-DOAS) observations of formaldehyde and nitrogen dioxide at three sites in Asia and comparison with the global chemistry transport model CHASER

... Moreover, the model has been examined through model comparison projects (e.g., Tian et al., 2015;Huntzinger et al., 2017). The VISIT model is also coupled with the MIROC-CHASER atmosphere 175 and chemistry model (Ha et al., 2021;He et al., 2022;Sekiya et al., 2018;Sudo et al., 2002) and the COCO ocean model (Hasumi, 2006) to build the Earth System Model (Hajima et al., 2020), but it can be run alternatively as a stand-alone model. ...

Introducing new lightning schemes into the CHASER (MIROC) chemistry–climate model

... Studies have found that HCHO mainly comes from natural sources, among which isoprene oxidation accounts for the largest contribution, reaching 50% in strong source areas [15,16]. Moreover, changes in biogenic emissions have a strong driving effect on the seasonal regulation of HCHO [17]. Photolysis of alkenes yields HCHO at the fastest rate, while aromatics and alkanes yield HCHO at a lower rate [18]. ...

MAX-DOAS observations of formaldehyde and nitrogen dioxide at three sites in Asia and comparison with the global chemistry transport model CHASER

... Most likely, such a spatiotemporal distribution of FNR is related to variations in the HCHO content in the troposphere. According to [71], the maximal HCHO concentration was registered in summer and was related to more effective photolysis and an increase in the natural emission of VOCs (e.g., isoprene). An analysis of the zonal distribution of the HCHO and NO 2 mixing ratios in July and January (not provided) by the WRF-Chem model demonstrated that the increased FNR at~2 km in July was caused by a significant decrease in NO 2 (by~10 times) at this height relative to that in the near-surface layer and by the increase in the HCHO content in summer. ...

Continuous multi-component MAX-DOAS observations for the planetary boundary layer ozone variation analysis at Chiba and Tsukuba, Japan, from 2013 to 2019

Progress in Earth and Planetary Science

... Moreover, the model's accuracy was comparable to previous studies. For instance, Balamurugan et al. reported an average R value of 0.55 for PM 2.5 between in situ measurements and GEOS-Chem simulations in 10 German cities before the COVID-19 pandemic (January-May 2019) (Balamurugan et al., 2022 (Kong et al., 2020;Lu et al., 2024). Although the correlation for O 3 was 0.53 from February to March 2019 over China, as simulated by Lu et al., this was likely due to the exclusion of significantly reduced NO X emission sites and the limited number of ground observation stations (Lu et al., 2024). ...

Evaluation and uncertainty investigation of the NO2, CO and NH3 modeling over China under the framework of MICS-Asia III

... Sensitivity of PM 2.5 variations in Delhi-NCR to emissions from CRB The major air pollutants are simulated using the Community Multiscale Air Quality Modelling System (CMAQ) with control emissions (see Methods) 44 . Because of the coarse horizontal resolution (30 × 30 km) of the model compared to the distance between some of the sites, we show the regionally averaged observation and model comparisons of PM 2.5 and CO for 2022 (Fig. 5). ...

Model inter-comparison for PM2.5 Components over urban areas in Japan in the J-STREAM framework

Atmosphere

... Thus, we present our GEMM estimates as the primary results. However, as the IER model was developed earlier, it has been widely used for quantifying the health impact of air pollution (e.g., Cohen et al., 2017;Lelieveld et al., 2015;Seposo et al., 2019). Specifically, the IER model described by Burnett et al. (2014) is represented by probabilistic distributions of parameters composed of 1,000 possible levels. ...

Effect of global atmospheric aerosol emission change on PM 2.5 -related health impacts

... We selected thirteen models that have all the variables needed for all historical and single forcing simulations (Supplementary Table S1). They are the Australian Community Climate and Earth System Simulator Climate Model Version 2 climate model (ACCESS-CM2) 61 , the Australian Community Climate and Earth System Simulator Earth System Model version 1.5 (ACCESS-ESM1-5) 62 , the Beijing Climate Center Climate System Model (BCC-CSM2-MR) 63 , the Canadian Earth System Model version 5 (CanESM5) 64 , the National Center for Atmospheric Research Community Earth System Model Version 2 (CESM2) 65 , the sixth generation Centre National de Recherches Météorologique Coupled Model (CNRM-CM6-1) 66 , the GFDL's Earth System Model Version 4 (GFDL-ESM4) 67 , the Goddard Insitute for Space Studies climate model (GISS-E2-1-G) 68 , the Hadley Centre Global Environment Model version 3 (HadGEM3-GC31-LL) 69 , the Institute Pierre-Simon Laplace Climate Model (IPSL-CM6A-LR) 70 , the Model for Interdisciplinary Research on Climate version 6 (MIROC6) 71 , the Meteorological Research Institute Earth System Model (MRI-ESM2-0) 72 and the second version of the coupled Norwegian Earth System Model (NorESM2) 73 . ...

Description and basic evaluation of simulated mean state, internal variability, and climate sensitivity in MIROC6

... Although remarkable advances have been made in air quality modeling, large uncertainties remain. Model intercomparison studies within the framework of MICS-Asia III revealed that the poorly/differently parameterized physical, dynamical, and chemical processes of models greatly contribute to the large CO variability Kong et al., 2019). To provide insights into the impact of different models on the uncertainties of inverted CO emissions, sensitivity tests are performed using the CMAQv4.7.1 and CMAQv5.0.2 models. ...

Evaluation and uncertainty investigation of the NO2, CO and NH3 modeling over China under the framework of MICS-Asia III

Atmospheric Chemistry and Physics Discussions