scholarly journals Spatiotemporal variations of the δ(O<sub>2</sub>/N<sub>2</sub>), CO<sub>2</sub> and δ(APO) in the troposphere over the Western North Pacific

2021 ◽  
Author(s):  
Shigeyuki Ishidoya ◽  
Kazuhiro Tsuboi ◽  
Yosuke Niwa ◽  
Hidekazu Matsueda ◽  
Shohei Murayama ◽  
...  
Keyword(s):  
North Pacific ◽  
Western North Pacific ◽  
Interannual Variation ◽  
Transport Model ◽  
Atmospheric Transport ◽  
Biological Activities ◽  
Seasonal Cycles ◽  
Sample Collection ◽  
Marine Biological ◽  
Air Sample

Abstract. We analyzed air samples collected onboard a cargo aircraft C-130 over the western North Pacific from May 2012 to March 2020 for atmospheric δ(O2/N2) and CO2 amount fraction. We corrected for significant artificial fractionation of O2 and N2 caused by thermal diffusion during the air sample collection by using the simultaneously-measured δ(Ar/N2). The observed seasonal cycles of the δ(O2/N2) and atmospheric potential oxygen (δ(APO)) varied nearly in opposite phase to that of the CO2 amount fraction at all latitudes and altitudes. Seasonal amplitudes of δ(APO) decreased with latitude from 34 to 25° N, as well as with increasing altitude from the surface to 6 km by 50–70 %, while those of CO2 amount fraction decreased by less than 20 %. By comparing the observed values with the simulated δ(APO) and CO2 amount fraction values generated by an atmospheric transport model, we found that the seasonal δ(APO) cycle in the middle troposphere was modified significantly by a superposition of the northern and southern hemispheric seasonal cycles due to the inter-hemispheric mixing of air. The simulated δ(APO) underestimated the observed interannual variation in δ(APO) significantly, probably due to the interannual variation in the annual mean air-sea O2 flux. Interannual variation in δ(APO) driven by the net marine biological activities, obtained by subtracting the assumed solubility-driven component of δ(APO) from the total variation, indicated a clear evidence of influence on annual sea-to-air (air-to-sea) marine biological O2 flux during El Niño (La Niña). By analyzing the observed secular trends of δ(O2/N2) and CO2 amount fraction, global average terrestrial biospheric and oceanic CO2 uptakes for the period 2012–2019 were estimated to be (1.8 ± 0.9) and (2.8 ± 0.6) Pg a−1 (C equivalents), respectively.

scholarly journals Latitudinal distributions of organic nitrogen and organic carbon in marine aerosols over the western North Pacific

2011 ◽  
Vol 11 (7) ◽  
pp. 3037-3049 ◽  
Author(s):  
Y. Miyazaki ◽  
K. Kawamura ◽  
J. Jung ◽  
H. Furutani ◽  
M. Uematsu
Keyword(s):  
Organic Carbon ◽  
North Pacific ◽  
Western North Pacific ◽  
Organic Nitrogen ◽  
Biological Activities ◽  
Organic Aerosols ◽  
Total Carbon ◽  
Isotopic Ratios ◽  
Study Region ◽  
Marine Biological

Abstract. Marine aerosol samples were collected over the western North Pacific along the latitudinal transect from 44° N to 10° N in late summer 2008 for measurements of organic nitrogen (ON) and organic carbon (OC) as well as isotopic ratios of total nitrogen (TN) and total carbon (TC). Increased concentrations of methanesulfonic acid (MSA) and diethylammonium (DEA+) at 40–44° N and subtropical regions (10–20° N) together with averaged satellite chlorophyll-a data and 5-day back trajectories suggest a significant influence of marine biological activities on aerosols in these regions. ON exhibited increased concentrations up to 260 ngN m−3 in these marine biologically influenced aerosols. Water-insoluble organic nitrogen (WION) was found to be the most abundant nitrogen in the aerosols, accounting for 55 ± 16% of total aerosol nitrogen. In particular, the average WION/ON ratio was as high as 0.93 ± 0.07 at 40–44° N. These results suggest that marine biological sources significantly contributed to ON, a majority of which is composed of water-insoluble fractions in the study region. Analysis of the stable carbon isotopic ratios (δ13C) indicated that, on average, marine-derived carbon accounted for ~88 ± 12% of total carbon in the aerosols. In addition, the δ13C showed higher values (from −22 to −20‰) when ON/OC ratios increased from 0.15 to 0.35 in marine biologically influenced aerosols. These results clearly show that organic nitrogen is enriched in organic aerosols originated from an oceanic region with high biological productivity, indicating a preferential transfer of nitrogen-containing organic compounds from the sea surface to the marine atmosphere. Both WION concentrations and WION/water-insoluble organic carbon (WIOC) ratios tended to increase with increasing local wind speeds, indicating that sea-to-air emissions of ON via sea spray contribute significantly to the marine organic aerosols over the study region.

scholarly journals Latitudinal distributions of organic nitrogen and organic carbon in marine aerosols over the western North Pacific

2010 ◽  
Vol 10 (11) ◽  
pp. 28721-28753 ◽  
Author(s):  
Y. Miyazaki ◽  
K. Kawamura ◽  
J. Jung ◽  
H. Furutani ◽  
M. Uematsu
Keyword(s):  
Organic Carbon ◽  
North Pacific ◽  
Western North Pacific ◽  
Organic Nitrogen ◽  
Biological Activities ◽  
Organic Aerosols ◽  
Total Carbon ◽  
Isotopic Ratios ◽  
Study Region ◽  
Marine Biological

Abstract. Marine aerosol samples were collected over the western North Pacific along the latitudinal transect from 44° N to 10° N in late summer 2008 for measurements of organic nitrogen (ON) and organic carbon (OC) as well as isotopic ratios of total nitrogen (TN) and total carbon (TC). Increased concentrations of methanesulfonic acid (MSA) and diethylammonium (DEA+) at 40–44° N and subtropical regions (10–20° N) together with averaged satellite chlorophyll a data and 5-day back trajectories suggest a significant influence of marine biological activities on aerosols in these regions. ON exhibited increased concentrations up to 260 ngN m−3 in these marine biologically influenced aerosols. Water-insoluble organic nitrogen (WION) was found to be the most abundant nitrogen in the aerosols, accounting for 55 ± 16% of total aerosol nitrogen. In particular, the average WION/ON ratio was as high as 0.93 ± 0.07 at 40–44° N. These results suggest that marine biological sources significantly contributed to ON, a majority of which is composed of water-insoluble fractions in the study region. Analysis of the stable carbon isotopic ratios (δ13C) indicated that, on average, marine-derived carbon accounted for ~88 ± 12% of total carbon in the aerosols. In addition, the δ13C increased from −22 to −20‰ when ON/OC ratios increased from 0.15 to 0.35 in marine biologically influenced aerosols. These results clearly show that organic nitrogen is enriched in organic aerosols originated from an oceanic region with high biological productivity, indicating a preferential transfer of nitrogen-containing organic compounds from the sea surface to the marine atmosphere. Both WION concentrations and WION/water-insoluble organic carbon (WIOC) ratios showed positive correlations with local wind speeds, suggesting that sea-to-air emissions of ON via sea spray significantly contributes to marine organic aerosols over the study region.

scholarly journals Effects of monsoon trough interannual variation on tropical cyclogenesis over the western North Pacific

2014 ◽  
Vol 41 (12) ◽  
pp. 4332-4339 ◽  
Author(s):  
Xi Cao ◽  
Tim Li ◽  
Melinda Peng ◽  
Wen Chen ◽  
Guanghua Chen
Keyword(s):  
North Pacific ◽  
Western North Pacific ◽  
Interannual Variation ◽  
Monsoon Trough ◽  
Tropical Cyclogenesis

scholarly journals Long-term (2001–2012) trends of carbonaceous aerosols from a remote island in the western North Pacific: an outflow region of Asian pollutants

2018 ◽  
Vol 18 (2) ◽  
pp. 1291-1306 ◽  
Author(s):  
Suresh K. R. Boreddy ◽  
M. Mozammel Haque ◽  
Kimitaka Kawamura
Keyword(s):  
Organic Carbon ◽  
Long Range ◽  
North Pacific ◽  
Western North Pacific ◽  
Atmospheric Transport ◽  
Carbonaceous Aerosols ◽  
Central Pacific ◽  
Air Masses ◽  
Photochemical Formation

Abstract. The present study reports on long-term trends of carbonaceous aerosols in total suspended particulate (TSP) samples collected at Chichijima in the western North Pacific during 2001–2012. Seasonal variations of elemental carbon (EC), organic carbon (OC), and water-soluble organic carbon (WSOC) concentrations showed maxima in winter to spring and minima in summer. These seasonal differences in the concentrations of carbonaceous aerosols were associated with the outflows of polluted air masses from East Asia, which are clearly distinguishable from pristine air masses from the central Pacific. The higher concentrations of carbonaceous aerosols during winter to spring are associated with long-range atmospheric transport of East Asian continental polluted air masses, whereas lower concentrations may be due to pristine air masses from the central Pacific in summer. The annual trends of OC ∕ EC (+0.46 % yr−1), WSOC (+0.18 % yr−1) and WSOC ∕ OC (+0.08 % yr−1) showed significant (p  <  0.05) increases during the period of 2001–2012, suggesting that photochemical formation of WSOC and its contributions to secondary organic aerosols (SOAs) have increased over the western North Pacific via long-range atmospheric transport. We found a significant increase (+0.33 % yr−1) in nss-K+ ∕ EC ratios, demonstrating that concentrations of biomass-burning-derived carbonaceous aerosols have increased, while those of primary fossil-fuel-derived aerosols have decreased over the western North Pacific. Further, secondary biogenic emissions are also important over the western North Pacific as inferred from a significant increase (+0.14 % yr−1) in the concentrations of methanesulfonate (MSA−, a tracer for biogenic sources). This point was further supported by a moderate correlation (r = 0.40) between WSOC and MSA−. We also found a significant increase in OC ∕ TC (total carbon) and WSOC ∕ TC ratios, further suggesting that photochemical formation of WSOC and its contributions to SOAs have increased over the western North Pacific during 2001–2012 via long-range atmospheric transport from East Asia.

scholarly journals Thirteen-years of observations on primary sugars and sugar alcohols over remote Chichijima Island in the western North Pacific

2017 ◽  
Author(s):  
Santosh Kumar Verma ◽  
Kimitaka Kawamura ◽  
Jing Chen ◽  
Pingqing Fu
Keyword(s):  
Long Range ◽  
North Pacific ◽  
Western North Pacific ◽  
Atmospheric Transport ◽  
Fungal Spores ◽  
Pollen Grains ◽  
Early Summer ◽  
Total Sugar ◽  
Late Winter ◽  
Sugar Alcohols

Abstract. In order to understand the atmospheric transport of bioaerosols, we conducted long-term observations of primary sugars and sugar alcohols over remote Chichijima Island in the western North Pacific from 2001 to 2013. Our results showed that concentrations of total sugar compounds for 13 years ranged from 1.2 to 310 ng m−3 (average, 46 ± 49 ng m−3). We found that atmospheric circulations significantly affect the seasonal variations of bioaerosol distributions over the western North Pacific. The primary sugars (glucose and fructose) maximized in summer, possibly due to a decreased transport of Asian aerosols and increased local emission of vegetation products from the vascular plants in Chichijima. We also found higher concentrations of sugar components (arabitol, mannitol and trehalose) in more recent years during summer/autumn, suggesting an enhanced emission of fungal and microbial species over the island. Sucrose peaked in late winter to early spring, indicating a springtime pollen contribution by long-range atmospheric transport, while elevated concentrations of sucrose in early summer could be assumed to be long-range transport of soil dust from Southeast Asia to Chichijima. Positive matrix factorization analyses suggested the locally emitted sugar compounds as well as long-range transported air borne pollen grains, microbes and fungal spores are the major contributors to total sugar compounds in the Chichijima aerosols. Backward air mass trajectories support the atmospheric transport of continental aerosols from the Asian continent during winter/spring over Chichijima.

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