Chemical composition of aerosol, sea fog, and rainwater in the marine boundary layer of the northwestern North Pacific and its marginal seas

2002 ◽  
Vol 107 (D24) ◽  
Author(s):  
Motoki Sasakawa
Keyword(s):  
Boundary Layer ◽  
Chemical Composition ◽  
North Pacific ◽  
Marine Boundary Layer ◽  
Marginal Seas ◽  
Sea Fog

scholarly journals Modelling the impacts of iodine chemistry on the northern Indian Ocean marine boundary layer

2021 ◽  
Vol 21 (11) ◽  
pp. 8437-8454
Author(s):  
Anoop S. Mahajan ◽  
Qinyi Li ◽  
Swaleha Inamdar ◽  
Kirpa Ram ◽  
Alba Badia ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Chemical Composition ◽  
Indian Ocean ◽  
Marine Boundary Layer ◽  
Indian Subcontinent ◽  
Winter Period ◽  
Monsoon Period ◽  
Mean Values ◽  
Iodine Chemistry ◽  
Inorganic Iodine

Abstract. Recent observations have shown the ubiquitous presence of iodine oxide (IO) in the Indian Ocean marine boundary layer (MBL). In this study, we use the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem version 3.7.1), including halogen (Br, Cl, and I) sources and chemistry, to quantify the impacts of the observed levels of iodine on the chemical composition of the MBL. The model results show that emissions of inorganic iodine species resulting from the deposition of ozone (O3) on the sea surface are needed to reproduce the observed levels of IO, although the current parameterizations overestimate the atmospheric concentrations. After reducing the inorganic emissions by 40 %, a reasonable match with cruise-based observations is found, with the model predicting values between 0.1 and 1.2 pptv across the model domain MBL. A strong seasonal variation is also observed, with lower iodine concentrations predicted during the monsoon period, when clean oceanic air advects towards the Indian subcontinent, and higher iodine concentrations predicted during the winter period, when polluted air from the Indian subcontinent increases the ozone concentrations in the remote MBL. The results show that significant changes are caused by the inclusion of iodine chemistry, with iodine-catalysed reactions leading to regional changes of up to 25 % in O3, 50 % in nitrogen oxides (NO and NO2), 15 % in hydroxyl radicals (OH), 25 % in hydroperoxyl radicals (HO2), and up to a 50 % change in the nitrate radical (NO3), with lower mean values across the domain. Most of the large relative changes are observed in the open-ocean MBL, although iodine chemistry also affects the chemical composition in the coastal environment and over the Indian subcontinent. These results show the importance of including iodine chemistry in modelling the atmosphere in this region.

scholarly journals Modelling the Impacts of Iodine Chemistry on the Northern Indian Ocean Marine Boundary Layer

2020 ◽  
Author(s):  
Anoop S. Mahajan ◽  
Qinyi Li ◽  
Swaleha Inamdar ◽  
Kirpa Ram ◽  
Alba Badia ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Chemical Composition ◽  
Indian Ocean ◽  
Marine Boundary Layer ◽  
Indian Subcontinent ◽  
Winter Period ◽  
Monsoon Period ◽  
The Indian Ocean ◽  
Iodine Chemistry ◽  
Inorganic Iodine

Abstract. Recent observations have shown the ubiquitous presence of iodine oxide (IO) in the Indian Ocean marine boundary layer (MBL). In this study, we use the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem version 3.7.1), including halogens (Br, Cl and I) sources and chemistry, to quantify the impacts of the observed levels of iodine on the chemical composition of the MBL. The model results show that emissions of inorganic iodine species resulting from the deposition of ozone (O3) on the sea surface are needed to reproduce the observed levels of IO, although the current parameterisations overestimate the atmospheric concentrations. After reducing the inorganic emissions by 40 %, a reasonable match with cruise-based observations is found. A strong seasonal variation is also observed, with lower iodine concentrations predicted during the monsoon period when clean oceanic air advects towards the Indian subcontinent, and higher iodine concentrations predicted during the winter period, when polluted air from the Indian subcontinent increases the ozone concentrations in the remote MBL. The results show that significant changes are caused by the inclusion of iodine chemistry, with iodine catalysed reactions leading to regional changes of up to 25 % in O3, 50 % in nitrogen oxides (NO and NO2), 15 % in hydroxyl radicals (OH), 25 % in hydroperoxyl radicals (HO2), and up to a 50 % change in the nitrate radical (NO3). Most of the large relative changes are observed in the open ocean MBL, although iodine chemistry also affects the chemical composition in the coastal environment and over the Indian subcontinent. These results show the importance of including iodine chemistry in modelling the atmosphere in this region.

scholarly journals Effects of aerosol organics on cloud condensation nucleus (CCN) concentration and first indirect aerosol effect

2008 ◽  
Vol 8 (3) ◽  
pp. 9783-9818 ◽  
Author(s):  
J. Wang ◽  
Y.-N. Lee ◽  
P. H. Daum ◽  
J. Jayne ◽  
M. L. Alexander
Keyword(s):  
Boundary Layer ◽  
Chemical Composition ◽  
Large Scale ◽  
Marine Boundary Layer ◽  
Volume Fraction ◽  
Thin Layers ◽  
Detailed Knowledge ◽  
Organic Species ◽  
Aerosol Effect ◽  
Scale Models

Abstract. Aerosol microphysics, chemical composition, and CCN properties were measured on the Department of Energy Gulfstream-1 aircraft during the Marine Stratus/Stratocumulus Experiment (MASE) conducted over the coastal waters between Point Reyes National Seashore and Monterey Bay, California, in July 2005. Aerosols measured during MASE included free tropospheric aerosols, marine boundary layer aerosols, and aerosols with high organic concentration within a thin layer above the cloud. Closure analysis was carried out for all three types of aerosols by comparing the measured CCN concentrations at 0.22% supersaturation to those predicted based on size distribution and chemical composition using Köhler theory. The effect of aerosol organic species on predicted CCN concentration was examined using a single hygroscopicity parameterization. For aerosols with organics volume fraction up to 70%, such as the marine boundary layer and free troposphere aerosols, CCN concentration and the corresponding first indirect aerosol effect are insensitive to the properties of organics, and can be accurately predicted with a constant hygroscopicity for all organic species. This simplification can facilitate the prediction of indirect aerosol effects using physically-based parameterizations in large scale models. However, for the aerosols within the thin layers above clouds, organics contributed up to 90% of the total aerosol volume, and a detailed knowledge of organic hygroscopicity is required to accurately predict CCN concentrations. Derivations of organic properties in future closure studies, when aerosols are dominated by organic species, would help constrain the descriptions of organics and aerosol-cloud parameterizations in large scale models.

Aerosol concentrations and composition in the North Pacific marine boundary layer

2017 ◽  
Vol 171 ◽  
pp. 165-172 ◽  
Author(s):  
Yongjoo Choi ◽  
Tae Siek Rhee ◽  
Jeffrey L. Collett ◽  
Taehyun Park ◽  
Seung-Myung Park ◽  
...  
Keyword(s):  
Boundary Layer ◽  
North Pacific ◽  
Marine Boundary Layer ◽  
The North ◽  
The North Pacific
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