Characteristics and emissions of isoprene and other non-methane hydrocarbons in the Northwest Pacific Ocean and responses to atmospheric aerosol deposition

Wu, Ying‐Cui; Gao, Xuxu; Zhang, Honghai; Liu, Yong-zheng; Wang, Jian; Feng, Xinbin; Zhang, Guiling; Chen, Zhaohui

doi:10.1016/j.scitotenv.2023.162808

Cited by 4 publications

(3 citation statements)

References 71 publications

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“…Atlantic Ocean (Tran et al, 2013), but were larger than those reported values in the North Sea (Broadgate et al, 1997) and the Northwest Pacific Ocean (Li et al, 2019;Wu et al, 2023) (Table S10).…”

Section: Sea-to-air Fluxes Of Nmhcscontrasting

confidence: 59%

Roles of oceanic ventilation and terrestrial outflow in the atmospheric non-methane hydrocarbons over the Chinese marginal seas

Wang,

Xue,

et al. 2024

Preprint

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Abstract. Non-methane hydrocarbons (NMHCs) in the marine atmosphere have been extensively studied due to their important roles in regulating the atmospheric chemistry and climate. However, very little is known about the distribution and sources of NMHCs in the lower atmosphere over the marginal seas of China. Herein, we characterized the atmospheric NMHCs (C2-C5) in both the coastal cities and marginal seas of China in spring 2021, with a focus on identifying the sources of NMHCs in the coastal atmosphere. The NMHCs in urban atmospheres, especially for alkanes, were significantly higher compared to that in marine atmosphere, suggesting that terrestrial NMHCs may serve as an important reservoir/source of the marine atmosphere. A significant correlation was observed between the alkane concentrations and the distances from sampling sites to the nearest land or retention of air mass over land, indicating that alkanes in the marine atmosphere are largely influenced by terrestrial inputs through air-mass transport. For alkenes, a greater impact from oceanic emissions was determined due to the lower terrestrial concentrations, short atmospheric lifetime, and substantial sea-to-air fluxes of alkenes compared to alkanes (489 ± 454 vs 129 ± 106 nmol m-2 d-1). As suggested by the positive matrix factorization, terrestrial inputs contributed to 89 % of alkanes and 69.6 % of alkenes in Chinese marginal seas, subsequently contributing to 84 % of the ozone formation potential associated with C2-C5 NMHCs. These findings underscore the significance of terrestrial outflow in controlling the distribution and composition of atmospheric NMHCs in the marginal seas of China.

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Section: Sea-to-air Fluxes Of Nmhcscontrasting

confidence: 59%

Roles of oceanic ventilation and terrestrial outflow in the atmospheric non-methane hydrocarbons over the Chinese marginal seas

Wang,

Xue,

et al. 2024

Preprint

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“…Additionally, larger sea‐to‐air fluxes of isoprene were found in the KOE (46.0 ± 13.0 nmol m −2 day −1 ) compared to the subtropical NWPO (23.6 ± 7.99 nmol m −2 day −1 ). Previous field studies in the Northwest Pacific reported similar isoprene fluxes of 41.7 ± 80.4 nmol m −2 day −1 (Wu et al., 2023) and 43.4 ± 33.8 nmol m −2 day −1 (Li et al., 2019). From the monthly global maps of calculated isoprene emissions (Booge et al., 2016) in October, a distinct difference between KOE and the subtropical NWPO was found with emissions of ∼35 and ∼20 nmol m −2 day −1 , respectively.…”

Section: Discussionmentioning

confidence: 55%

Isoprene Production and Its Driving Factors in the Northwest Pacific Ocean

Wang,

Zhang,

Booge

et al. 2023

Global Biogeochemical Cycles

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Marine isoprene plays a crucial role in the formation of secondary organic aerosol within the remote marine boundary layer. Due to scarce field measurements of oceanic isoprene and limited laboratory‐based studies of isoprene production, assessing the importance of marine isoprene on atmospheric chemistry and climate is challenging. Calculating in‐field isoprene production rates is a crucial step to predict marine isoprene concentrations and the subsequent emissions to the atmosphere. The distribution, sources, and dominant environmental factors of isoprene were determined in the Northwest Pacific Ocean in 2019. The nutrient enrichment in the Kuroshio Oyashio Extension (KOE) surface seawater, driven by the upwelling and atmospheric deposition, promoted the growth of phytoplankton and elevated the isoprene concentration. This was confirmed by observed responses of isoprene to nutrients and aerosol dust additions in a ship‐based incubation experiment, where the isoprene concentrations increased by 70% (t = 4.417, p < 0.001) and 35% (t = 2.387, p < 0.05), respectively. Biogenic isoprene production rates in the deck incubation experiments were positively related to chlorophyll a, temperature, and solar radiation, with an average production of 7.33 ± 4.27 pmol L−1 day−1. Photochemical degradation of dissolved organic matter was likely an abiotic source of isoprene, contributing to approximately 14% of the total production. Driven by high isoprene production and extreme physical disturbance, the KOE showed very high emissions of isoprene of 46.0 ± 13.0 nmol m−2 day−1, which led to a significant influence on the oxidative capacity of the local atmosphere.

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“…The loss through air-sea exchange was calculated based on the isoprene flux, as shown in Equation (6). Since the amount of isoprene in the atmosphere relative to the sea surface concentration is negligible [19,77], the sea-air isoprene flux (in nmol m −2 day −1 ) can be calculated using isoprene Cw, where kAS can be obtained through empirical relationships with 10 m wind speed (U10, in m s −1 ) and sea surface temperature (SST, in °C) [20,34,78].…”

Section: Isoprene Production Modelmentioning

confidence: 99%

Machine Learning to Characterize Biogenic Isoprene Emissions and Atmospheric Formaldehyde with Their Environmental Drivers in the Marine Boundary Layer

Wang,

Xue

et al. 2024

Atmosphere

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Oceanic biogenic emissions exert a significant impact on the atmospheric environment within the marine boundary layer (MBL). This study employs the extreme gradient boosting (XGBoost) machine learning method and clustering method combined with satellite observations and model simulations to discuss the effects of marine biogenic emissions on MBL formaldehyde (HCHO). The study reveals that HCHO columnar concentrations peaked in summer with 8.25 × 1015 molec/cm2, but the sea–air exchange processes controlled under the wind and sea surface temperature (SST) made marine biogenic emissions represented by isoprene reach their highest levels in winter with 95.93 nmol/m2/day. Analysis was conducted separately for factors influencing marine biogenic emissions and affecting MBL HCHO. It was found that phytoplankton functional types (PFTs) and biological degradation had a significant impact on marine biogenic emissions, with ratio range of 0.07~15.87 and 1.02~5.42 respectively. Machine learning methods were employed to simulate the conversion process of marine biogenic emissions to HCHO in MBL. Based on the SHAP values of the learning model, the importance results indicate that the factors influencing MBL HCHO mainly included NO2, as well as temperature (T) and relative humidity (RH). Specifically, the influence of NO2 on atmospheric HCHO was 1.3 times that of T and 1.6 times that of RH. Wind speed affected HCHO by influencing both marine biogenic emission and the atmospheric physical conditions. Increased marine biogenic emissions in air masses heavily influenced by human activities can reduce HCHO levels to some extent. However, in areas less affected by human activities, marine biogenic emissions can lead to higher levels of HCHO pollution. This research explores the impact of marine biogenic emissions on the HCHO status of the MBL under different atmospheric chemical conditions, offering significant insights into understanding chemical processes in marine atmospheres.

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Characteristics and emissions of isoprene and other non-methane hydrocarbons in the Northwest Pacific Ocean and responses to atmospheric aerosol deposition

Cited by 4 publications

References 71 publications

Roles of oceanic ventilation and terrestrial outflow in the atmospheric non-methane hydrocarbons over the Chinese marginal seas

Roles of oceanic ventilation and terrestrial outflow in the atmospheric non-methane hydrocarbons over the Chinese marginal seas

Isoprene Production and Its Driving Factors in the Northwest Pacific Ocean

Machine Learning to Characterize Biogenic Isoprene Emissions and Atmospheric Formaldehyde with Their Environmental Drivers in the Marine Boundary Layer

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