Aerosol dynamics in the equatorial Pacific marine boundary layer: Microphysics, diurnal cycles and entrainment

1996 ◽  
Vol 23 (7) ◽  
pp. 733-736 ◽  
Author(s):  
A. D. Clarke ◽  
Z. Li ◽  
M. Litchy
Keyword(s):  
Boundary Layer ◽  
Marine Boundary Layer ◽  
Equatorial Pacific ◽  
Aerosol Dynamics ◽  
Diurnal Cycles

scholarly journals Contribution of dissolved organic matter to submicron water-soluble organic aerosols in the marine boundary layer over the eastern equatorial Pacific

2016 ◽  
Author(s):  
Yuzo Miyazaki ◽  
Sean Coburn ◽  
Kaori Ono ◽  
David T. Ho ◽  
R. Bradley Pierce ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Organic Carbon ◽  
Marine Boundary Layer ◽  
Organic Aerosols ◽  
Equatorial Pacific ◽  
Water Soluble ◽  
Total Carbon ◽  
Stable Carbon ◽  
Study Region ◽  
Eastern Equatorial Pacific

Abstract. Stable carbon isotopic compositions of water-soluble organic carbon (WSOC) and organic molecular markers were measured to investigate the relative contributions of the sea-surface sources to the water-soluble fraction of submicron organic aerosols collected over the eastern equatorial Pacific during the Tropical Ocean tRoposphere Exchange of Reactive halogens and Oxygenated VOCs (TORERO)/KA-12-01 cruise. On average, the water-soluble organic fraction of the total carbon (TC) mass in submicron aerosols was ~ 30–35 % in the open oceans, whereas it was ~ 60 % in the coastal oceans. The average stable carbon isotope ratio of WSOC (δ13CWSOC) was −19.8 ± 2.0 ‰, which was systematically higher than that of TC (δ13CTC) (−21.8 ± 1.4 ‰). We found that in both coastal and open oceans, the δ13CWSOC was close to the typical values of δ13C for dissolved organic carbon (DOC), ranging from −22 ‰ to −20 ‰ in surface seawater of tropical Pacific oceans. This suggests an enrichment of marine biological products in WSOC aerosols in the study region regardless of the oceanic area. In particular, enhanced levels of WSOC and biogenic organic marker compounds together with high values of WSOC/TC (~ 60 %) and δ13CWSOC were observed over upwelling areas and phytoplankton blooms, which was attributed to planktonic tissues being more enriched in δ13C. The δ13C analysis estimated that on average, marine sources contribute ~ 90 ± 25 % of the aerosol carbon, indicating the predominance of marine-derived carbon in the submicron WSOC. This conclusion is supported by Lagrangian trajectory analysis, which suggests that the majority of the sampling points on the ship had been exposed to marine boundary layer air for more than 80 % of the time during the previous 7 days. The combined analysis of the δ13C and monosaccharides, such as glucose and fructose, indicated that DOC concentration was the major factor controlling the concentration levels of the submicron WSOC regardless of the oceanic areas over the study region.

Production and loss of methanesulfonate and non-sea salt sulfate in the equatorial Pacific marine boundary layer

1996 ◽  
Vol 23 (7) ◽  
pp. 737-740 ◽  
Author(s):  
B. J. Huebert ◽  
D. J. Wylie ◽  
L. Zhuang ◽  
J. A. Heath
Keyword(s):  
Boundary Layer ◽  
Marine Boundary Layer ◽  
Equatorial Pacific ◽  
Sea Salt

Ozone in the marine boundary layer over the Pacific and Indian Oceans: Latitudinal gradients and diurnal cycles

1990 ◽  
Vol 95 (D8) ◽  
pp. 11847 ◽  
Author(s):  
James E. Johnson ◽  
Richard H. Gammon ◽  
Jimmy Larsen ◽  
Timothy S. Bates ◽  
Samuel J. Oltmans ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Marine Boundary Layer ◽  
Latitudinal Gradients ◽  
Diurnal Cycles ◽  
The Pacific

scholarly journals A new flexible multicomponent model for the study of aerosol dynamics in the marine boundary layer

Tellus B ◽  
2011 ◽  
Vol 63 (5) ◽  
pp. 1001-1025 ◽  
Author(s):  
Matthias Karl ◽  
Allan Gross ◽  
Liisa Pirjola ◽  
Caroline Leck
Keyword(s):  
Boundary Layer ◽  
Marine Boundary Layer ◽  
Aerosol Dynamics ◽  
Multicomponent Model

scholarly journals Free troposphere as the dominant source of CCN in the Equatorial Pacific boundary layer: long-range transport and teleconnections

2013 ◽  
Vol 13 (1) ◽  
pp. 1279-1326 ◽  
Author(s):  
A. D. Clarke ◽  
S. Freitag ◽  
R. M. C. Simpson ◽  
J. G. Hudson ◽  
S. G. Howell ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Marine Boundary Layer ◽  
Cloud Condensation Nuclei ◽  
Large Fraction ◽  
Deep Convection ◽  
Equatorial Pacific ◽  
Quasi Equilibrium ◽  
Free Troposphere ◽  
Low Carbon ◽  
Mixing Ratios

Abstract. Airborne aerosol measurements in the central equatorial Pacific during PASE (Pacific Atmospheric Sulfur Experiment) revealed that cloud condensation nuclei (CCN) activated in marine boundary layer (MBL) clouds were dominated by entrainment from the free troposphere (FT). About 65% entered at sizes effective as CCN in MBL clouds, while 25% entered the MBL too small to activate but subsequently grew via gas to particle conversion. The remaining 10% were inferred to be sea-salt aerosol; there was no discernable nucleation in the MBL. FT aerosols at low carbon monoxide (CO) mixing ratios (< 63 ppbv) were small and relatively volatile with a number mode around 30–40 nm dry diameter and tended to be associated with cloud outflow from distant deep convection (3000 km or more). Higher CO concentrations were commonly associated with trajectories from South America and the Amazon region (ca. 10 000 km away) and occurred in layers indicative of combustion sources partially scavenged by precipitation. These had number mode near 60–80 nm diameter with a large fraction already CCN.2 (those activated at 0.2% supersaturation and representative of MBL clouds) before entrainment into the MBL. Flight averaged concentrations of CCN.2 were similar for measurements near the surface, below the inversion and above the inversion, confirming that subsidence of FT aerosol dominated MBL CCN.2. Concurrent flight-to-flight variations of CCN.2 at all altitudes below 3 km imply MBL CCN.2 concentrations were in quasi-equilibrium with the FT over a 2–3 day time scale. This extended FT transport over thousands of kilometers indicates teleconnections between MBL CCN and cloud-scavenged sources of both natural and/or residual combustion origin. The low aerosol scattering and mass in such layers results in poor detection by satellite and this source of CCN is not represented in most current models. The measurements confirm nucleation in the MBL was not evident during PASE and argue against the CLAW hypothesis being effective in this region during PASE.

scholarly journals Contribution of dissolved organic matter to submicron water-soluble organic aerosols in the marine boundary layer over the eastern equatorial Pacific

2016 ◽  
Vol 16 (12) ◽  
pp. 7695-7707 ◽  
Author(s):  
Yuzo Miyazaki ◽  
Sean Coburn ◽  
Kaori Ono ◽  
David T. Ho ◽  
R. Bradley Pierce ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Organic Carbon ◽  
Marine Boundary Layer ◽  
Organic Aerosols ◽  
Equatorial Pacific ◽  
Water Soluble ◽  
Stable Carbon ◽  
Study Region ◽  
Chl A ◽  
Eastern Equatorial Pacific

Abstract. Stable carbon isotopic compositions of water-soluble organic carbon (WSOC) and organic molecular markers were measured to investigate the relative contributions of the sea surface sources to the water-soluble fraction of submicron organic aerosols collected over the eastern equatorial Pacific during the Tropical Ocean tRoposphere Exchange of Reactive halogens and Oxygenated VOCs (TORERO)/KA-12-01 cruise. On average, the water-soluble organic fraction of the total carbon (TC) mass in submicron aerosols was  ∼  30–35 % in the oceans with the low chlorophyll a (Chl a) concentrations, whereas it was  ∼  60 % in the high-Chl a regions. The average stable carbon isotope ratio of WSOC (δ13CWSOC) was −19.8 ± 2.0 ‰, which was systematically higher than that of TC (δ13CTC) (−21.8 ± 1.4 ‰). We found that in the oceans with both high and low Chl a concentrations the δ13CWSOC was close to the typical values of δ13C for dissolved organic carbon (DOC), ranging from −22 to −20 ‰ in surface seawater of the tropical Pacific Ocean. This suggests an enrichment of marine biological products in WSOC aerosols in the study region regardless of the oceanic area. In particular, enhanced levels of WSOC and biogenic organic marker compounds together with high values of WSOC / TC ( ∼  60 %) and δ13CWSOC were observed over upwelling areas and phytoplankton blooms, which was attributed to planktonic tissues being more enriched in δ13C. The δ13C analysis estimated that, on average, marine sources contribute  ∼  90 ± 25 % of the aerosol carbon, indicating the predominance of marine-derived carbon in the submicron WSOC. This conclusion is supported by Lagrangian trajectory analysis, which suggests that the majority of the sampling points on the ship had been exposed to marine boundary layer (MBL) air for more than 80 % of the time during the previous 7 days. The combined analysis of the δ13C and monosaccharides, such as glucose and fructose, demonstrated that DOC concentration was closely correlated with the concentration levels of submicron WSOC across the study region regardless of the oceanic area. The result implies that DOC may characterize background organic aerosols in the MBL over the study region.

scholarly journals Marine boundary layer over the subtropical southeast Pacific during VOCALS-REx – Part 1: Mean structure and diurnal cycle

2010 ◽  
Vol 10 (10) ◽  
pp. 4491-4506 ◽  
Author(s):  
D. A. Rahn ◽  
R. Garreaud
Keyword(s):  
Boundary Layer ◽  
Diurnal Cycle ◽  
Marine Boundary Layer ◽  
Lower Troposphere ◽  
Vertical Motion ◽  
Atmospheric Model ◽  
Diurnal Cycles ◽  
The Andes ◽  
Southeast Pacific ◽  
Westerly Flow

Abstract. Atmospheric subsidence over the subtropical southeast Pacific (SEP) leads to a low-level anticyclonic circulation, a cool sea surface and a cloud-topped marine boundary layer (MBL). Observations in this region from a major field campaign during October and November 2008, the VOCALS Regional Experiment, provide ample data to characterize the lower atmospheric features over the SEP. The observations are also useful to test the ability of an area-limited, high-resolution atmospheric model to simulate the SEP conditions. Observations and model-results (where appropriate) improve the characterization of the mean state (Part 1) and variability (Part 2) of the lower troposphere including circulation, MBL characteristics and the upsidence wave. Along 20° S the MBL is generally deeper offshore (1600 m at 85° W) but there is also considerable variability. MBL depth and variability decrease towards the coast and maximum inversion strength is detected between 74–76° W. Weather Research and Forecasting (WRF) simulations underestimate MBL height the most near the coast but improve offshore. Southeasterly trades prevail within the MBL although the wind speed decreases toward the coast. Above the MBL along the coast of Chile, flow is northerly, has a maximum at 3 km, and extends westward to ~74° W, apparently due to the mechanical blocking exerted by the Andes upon the westerly flow aloft. Mean MBL features along northern Chile (18–25° S) are remarkably similar (e.g., MBL depth just below 1 km) in spite of different SST. Observed diurnal cycles of the temperature at the coast and further offshore exhibit a number of conspicuous features that are consistent with the southwestward propagation of an upsidence wave initiated during late evening along the south Peru coast. Furthermore, the passage of the vertical motion results in either constructive or deconstructive interference with the radiatively-forced diurnal cycle of MBL depth. Interference is clearly seen in the soundings at Iquique which are driven by a strong upsidence wave contrary to the radiation-driven cycle, leading to a diurnal cycle opposite of the other sites. Because WRF simulations have a lower MBL height, the speed of the simulated gravity wave is slower than observations and accounts for most of the discrepancy between observed and simulated phase speeds.

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