The authors examine the equilibrium climatic response to the direct radiative effect （DRE） of mineral dust and sea salt aerosols in a doubled-CO2 climate with two-way coupling of aerosol-climate interactions.In resp...The authors examine the equilibrium climatic response to the direct radiative effect （DRE） of mineral dust and sea salt aerosols in a doubled-CO2 climate with two-way coupling of aerosol-climate interactions.In response to the drier and windier conditions,dust emissions increase by 26％ in the Sahara Desert and by 18％ on the global scale relative to present day.Sea salt emissions increase in high latitudes （＞60°） but decrease in middle latitudes （30°-60°） of both hemispheres due to the poleward shift of westerlies,leading to a 3％ decrease in global emissions.The burdens of dust and sea salt increase by 31％ and 7％ respectively,because reductions in rainfall over the tropical oceans increase the lifetime of particles in the warmer climate.The higher aerosol loading in the doubled-CO2 climate reinforces aerosol DRE by -0.2 W m-2,leading to an additional cooling of 0.1℃ at the surface compared with the climatic effects of aerosols in present day.The additional cooling from changes in natural aerosols compensates for up to 15％ of the regional warming induced by doubled CO2.展开更多
PM10 was monitored during 2008-2011 period at LUT and BON, two urban tropical stations close to each other at Saint-Pierre city, in Reunion Island (south-western Indian Ocean). During the study period, notable PM10 co...PM10 was monitored during 2008-2011 period at LUT and BON, two urban tropical stations close to each other at Saint-Pierre city, in Reunion Island (south-western Indian Ocean). During the study period, notable PM10 concentrations are observed at BON close to the coasts. At LUT, a more inland site, the daily PM10 concentration range between 13 and 70 μg/m3. Importantly, the limit value for the protection of the human health is systematically exceeded at BON while it is never exceeded at LUT. Also, the quality objective (QO: 30 μg/m3, on annual average) and the limit value for the human health protection (LV: 40 μg/m3, on annual average) are exceeded at BON each year during 2008-2011, while at LUT no regulatory values are exceeded. Nitrogen dioxide, an atmospheric tracer of anthropogenic activities was also monitored at LUT and BON. The mean diurnal NO2 variation is of the same level and order of magnitude and exhibits a similar pattern at both stations suggesting that distinct sources influence the PM10 at LUT and at BON. Chemical analysis was performed on daily filters sampled in September-November 2011 at the two stations to determine the sea salt contribution on PM10 across Saint-Pierre city. It showed that the sea salt contribution to the PM10 is 55% at BON in September 2011. The sea salt particles are therefore the main cause for the exceedances of the regulatory values of PM10 recorded at BON. The results importantly suggest that the notable PM10 concentrations measured at this urban marine site might have some but minor impact on human health.展开更多
We have developed a remote sea salt aerosol fluorescence spectroscopy system integrating a high-power industrial-grade femtosecond laser to enhance detection sensitivity and precision in complex environments.This syst...We have developed a remote sea salt aerosol fluorescence spectroscopy system integrating a high-power industrial-grade femtosecond laser to enhance detection sensitivity and precision in complex environments.This system successfully detects sea salt aerosol particles,achieving a detection limit of 0.015 ng/m^(3) for neutral Na element(Na I)at 589 nm,with a detection range of 30 m.Our findings demonstrate significant improvements in remote aerosol monitoring,addressing previous challenges in long-range and high-precision sensing with a detection accuracy previously unattainable below 10 ng/m^(3).展开更多
High volume aerosol samplers at Great Wall Station in Antarctica were used to collect 73 aerosol samples between January 2012 and November 2013. The main ions in these aerosol samples, Cl^-, NO3-, SO4^2-, Na＋, K＋, ...High volume aerosol samplers at Great Wall Station in Antarctica were used to collect 73 aerosol samples between January 2012 and November 2013. The main ions in these aerosol samples, Cl^-, NO3-, SO4^2-, Na＋, K＋, Ca2＋, Mg2＋, NH4＋, as well as methane sulfonic acid, were analyzed using ion chromatography. Trace metals in these samples, including Pb, Cu, Cd, V, Zn, Fe, and Al, were determined by inductively-coupled plasma mass spectrometry. Results showed that sea salt was the main component in aerosols at Great Wall Station. Most ions exhibited significant seasonal variations, with higher concentrations in summer and autumn than in winter and spring. Variations in ions and trace metals were related to several processes（or sources）, including sea salt emission, secondary aerosol formation, and anthropogenic pollution from both local and distant sources. The sources of ions and trace metals were identified using enrichment factor, correlation, and factor analyses. Clearly, Na＋, K＋, Ca2＋, and Mg2＋were from marine sources, while Cu, Pb, Zn, and Cd were from anthropogenic pollution, and Al and V were mainly from crustal sources.展开更多
Aerosol samples were collected in summer in Macao, a coastal city of the Pearl River Delta Region in China. Morphology, size, elemental composition, and mixing state of individual aerosol particles were determined by ...Aerosol samples were collected in summer in Macao, a coastal city of the Pearl River Delta Region in China. Morphology, size, elemental composition, and mixing state of individual aerosol particles were determined by scanning electron microscopy coupled energy dispersive X-ray （SEM/EDX） and transmission electron microscopy （TEM）. Based on the morphologies of 5711 aerosol particles, they consist of soot （32%）, mineral （17%）, secondary-（22%）, and unknown fine particles （29%）. The sizes of these particles were mostly distributed between 0.1 and 0.4 μm. Compositions of 202 mineral particles were obtained by SEM/EDX. Mineral particles were mainly classified into three types： Si-rich, Ca-rich, and Na-rich. The compositions of typical mineral particles can indicate their sources in sampling location. For example, mineral particles, collected along the main street, were associated with trace amounts of heavy metals, such as Zn, Ti, Mn, Ba, Pb, and As. TEM observations indicate that most Na-rich particles were aged sea salt particles （e.g., Na2SO4 and NaNO3） which formed through heterogeneous chemical reactions between sea salt and acidic gases. Additionally, aging time of soot was short in Macao due to high humidity, high temperature, and high levels of sunlight in Macao. Most of soot and fine mineral dust particles were internally mixed with secondary particles.展开更多
Morphological changes with decreasing relative humidity(RH) of supersaturated sea-salt aerosol droplets on a quartz substrate were observed using a high-speed video-camera.Stable gypsum(CaSO4·2H2O) or the metasta...Morphological changes with decreasing relative humidity(RH) of supersaturated sea-salt aerosol droplets on a quartz substrate were observed using a high-speed video-camera.Stable gypsum(CaSO4·2H2O) or the metastable hemihydrate(CaSO4·0.5H2O) were precipitated as the RH decreased.The dynamic process of crystal growth under steady-state humidity was studied by controlling the RH;the metastable hemihydrate was precipitated at 70.5%-77.1% RH,and the apparent crystal growth rate was between 1.42 and 2.33 μm3/s.Stable gypsum was formed at 80.7%-82.2% RH,and the apparent crystal growth rate was between 0.70 and 0.81 μm3/s.展开更多
We investigate the effects of sea-salt aerosol(SSA) activated as cloud condensation nuclei on the microphysical processes, precipitation, and thermodynamics of a tropical cyclone(TC). The Weather Research and Forecast...We investigate the effects of sea-salt aerosol(SSA) activated as cloud condensation nuclei on the microphysical processes, precipitation, and thermodynamics of a tropical cyclone(TC). The Weather Research and Forecasting model coupled with Chemistry(WRF-Chem) was used together with a parameterization of SSA production. Three simulations, with different levels of SSA emission(CTL, LOW, HIGH), were conducted. The simulation results show that SSA contributes to the processes of autoconversion of cloud water and accretion of cloud water by rain,thereby promoting rain formation. The latent heat release increases with SSA emission, slightly increasing horizontal wind speeds of the TC. The presence of SSA also regulates the thermodynamic structure and precipitation of the TC.In the HIGH simulation, higher latent heat release gives rise to stronger updrafts in the TC eyewall area, leading to enhanced precipitation. In the LOW simulation, due to decreased latent heat release, the temperature in the TC eye is lower, enhancing the downdrafts in the region; and because of conservation of mass, updrafts in the eyewall also strengthen slightly; as a result, precipitation in the LOW experiment is a little higher than that in the CTL experiment.Overall, the relationship between the precipitation rate and SSA emission is nonlinear.展开更多
Atmospheric circulation reconstruction based on glaciochemical records requires knowledge of chemical concentration controls, such as source, transport pathway and strength. To gain insight into these processes, the r...Atmospheric circulation reconstruction based on glaciochemical records requires knowledge of chemical concentration controls, such as source, transport pathway and strength. To gain insight into these processes, the relationships between glaciochemical records from two Northern Hemisphere sites (Mt. Logan in Yukon Territory and 20D in southern Greenland) and instrumental sea level pressure (SLP) series are investigated. Calibrations between Mt. Logan sea-salt sodium (ssNa+) concentration and SLP series show that ssNa+ concentrations are closely correlated with the autumntime (SON) Aleutian Low and the summertime (JJA) North Pacific Subtropical High. Both the deepened Aleutian Low and enhanced North Pacific Sub- tropical High strengthen the transport of sea-salt aerosols from the North Pacific to the Mt. Logan region. Calibrations between 20D ssNa+ concentrations and SLP series indicate that ssNa+ concentrations are closely related to the wintertime (Jan.) Icelandic Low. A deepening of the Icelandic Low strengthens winter storms and frequent cyclogenesis over the North Atlantic and pushes more sea-salt laden air masses to the Greenland ice sheet. Therefore, ice core ssNa+ records from the Mt. Logan region can be considered as a proxy for reconstructing the au- tumntime Aleutian Low and summertime North Pacific Subtropical High, and the ssNa+ records from Greenland ice core (20D) may provide a proxy for reconstructing the wintertime Icelandic Low.展开更多
Dry deposited particles, larger than 1.3 μm, were collected under clear, cloudy, and foggy conditions during a cruise, traversing the Yellow Sea and the East China Sea from 23 March to 8 April 2011. In these areas, a...Dry deposited particles, larger than 1.3 μm, were collected under clear, cloudy, and foggy conditions during a cruise, traversing the Yellow Sea and the East China Sea from 23 March to 8 April 2011. In these areas, air masses are influenced by pollution outflows from the Asian continent. The size and elemental composition of dry deposited particles were investigated using a scanning electron microscope. Number-size distributions of these particles were approximately lognormal. Under clear conditions, the mode size was about 5.0 μm, with a mean diameter of 6.9 μm. Under cloudy and foggy conditions, the mean diameters were 5.7 and 6.0 μm, respectively, but the mode sizes were vague. Non-mixed mineral particles, sea salt, and mixed mineral-sea salt particles were the major particle types. Correspondingly, Al and Si were the most frequently detected elements. Frequencies of K-, Ca-, and S-containing particles were highest under foggy conditions, while the frequency of Na-containing particles was lowest. These results indicate that fog favored sulfate production on the particles and led to the deposited mineral particles more abundant in secondary salt, suggesting the importance to consider the dependence of the comoosition of deoosited mineral narticles on weather as well as narticle size.展开更多
基金supported by the National Basic Research Program of China(973 program,Grant 2010CB951901)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant XDA05100503)
文摘The authors examine the equilibrium climatic response to the direct radiative effect （DRE） of mineral dust and sea salt aerosols in a doubled-CO2 climate with two-way coupling of aerosol-climate interactions.In response to the drier and windier conditions,dust emissions increase by 26％ in the Sahara Desert and by 18％ on the global scale relative to present day.Sea salt emissions increase in high latitudes （＞60°） but decrease in middle latitudes （30°-60°） of both hemispheres due to the poleward shift of westerlies,leading to a 3％ decrease in global emissions.The burdens of dust and sea salt increase by 31％ and 7％ respectively,because reductions in rainfall over the tropical oceans increase the lifetime of particles in the warmer climate.The higher aerosol loading in the doubled-CO2 climate reinforces aerosol DRE by -0.2 W m-2,leading to an additional cooling of 0.1℃ at the surface compared with the climatic effects of aerosols in present day.The additional cooling from changes in natural aerosols compensates for up to 15％ of the regional warming induced by doubled CO2.
文摘PM10 was monitored during 2008-2011 period at LUT and BON, two urban tropical stations close to each other at Saint-Pierre city, in Reunion Island (south-western Indian Ocean). During the study period, notable PM10 concentrations are observed at BON close to the coasts. At LUT, a more inland site, the daily PM10 concentration range between 13 and 70 μg/m3. Importantly, the limit value for the protection of the human health is systematically exceeded at BON while it is never exceeded at LUT. Also, the quality objective (QO: 30 μg/m3, on annual average) and the limit value for the human health protection (LV: 40 μg/m3, on annual average) are exceeded at BON each year during 2008-2011, while at LUT no regulatory values are exceeded. Nitrogen dioxide, an atmospheric tracer of anthropogenic activities was also monitored at LUT and BON. The mean diurnal NO2 variation is of the same level and order of magnitude and exhibits a similar pattern at both stations suggesting that distinct sources influence the PM10 at LUT and at BON. Chemical analysis was performed on daily filters sampled in September-November 2011 at the two stations to determine the sea salt contribution on PM10 across Saint-Pierre city. It showed that the sea salt contribution to the PM10 is 55% at BON in September 2011. The sea salt particles are therefore the main cause for the exceedances of the regulatory values of PM10 recorded at BON. The results importantly suggest that the notable PM10 concentrations measured at this urban marine site might have some but minor impact on human health.
基金supported by the National Natural Science Foundation of China(Nos.12074198,12061131010,and 12304381).
文摘We have developed a remote sea salt aerosol fluorescence spectroscopy system integrating a high-power industrial-grade femtosecond laser to enhance detection sensitivity and precision in complex environments.This system successfully detects sea salt aerosol particles,achieving a detection limit of 0.015 ng/m^(3) for neutral Na element(Na I)at 589 nm,with a detection range of 30 m.Our findings demonstrate significant improvements in remote aerosol monitoring,addressing previous challenges in long-range and high-precision sensing with a detection accuracy previously unattainable below 10 ng/m^(3).
基金supported by the National Natural Science Foundation of China (Grant nos. 41230529 and 41476172)the Chinese Polar Environment Comprehensive Investigation & Assessment Programs (Grant no. CHINARE2012-15 for 01-04-02, 02-01, and 03-0402)Chinese International Cooperation Projects, Chinese Arctic and Antarctic Adminstration (Grant nos. 2015DFG22010, IC201201, IC201308 and IC201513)
文摘High volume aerosol samplers at Great Wall Station in Antarctica were used to collect 73 aerosol samples between January 2012 and November 2013. The main ions in these aerosol samples, Cl^-, NO3-, SO4^2-, Na＋, K＋, Ca2＋, Mg2＋, NH4＋, as well as methane sulfonic acid, were analyzed using ion chromatography. Trace metals in these samples, including Pb, Cu, Cd, V, Zn, Fe, and Al, were determined by inductively-coupled plasma mass spectrometry. Results showed that sea salt was the main component in aerosols at Great Wall Station. Most ions exhibited significant seasonal variations, with higher concentrations in summer and autumn than in winter and spring. Variations in ions and trace metals were related to several processes（or sources）, including sea salt emission, secondary aerosol formation, and anthropogenic pollution from both local and distant sources. The sources of ions and trace metals were identified using enrichment factor, correlation, and factor analyses. Clearly, Na＋, K＋, Ca2＋, and Mg2＋were from marine sources, while Cu, Pb, Zn, and Cd were from anthropogenic pollution, and Al and V were mainly from crustal sources.
基金supported by the National Basic Research Program (973) of China (No.2006CB403701)the Macao Foundation for Development of Science and Technology (No.023/2006/A)+3 种基金the State Key Laboratory of Coal Resources and Safe Mining (China University of Mining and Technology) (No.SKLCRSM09KFB04)the China Postdoctoral Science Foundation Funded Project(No.20090461213)the Shandong Postdoctoral Science Innovation Foundation (No.200902016)the Independent Innovation Foundation of Shandong University
文摘Aerosol samples were collected in summer in Macao, a coastal city of the Pearl River Delta Region in China. Morphology, size, elemental composition, and mixing state of individual aerosol particles were determined by scanning electron microscopy coupled energy dispersive X-ray （SEM/EDX） and transmission electron microscopy （TEM）. Based on the morphologies of 5711 aerosol particles, they consist of soot （32%）, mineral （17%）, secondary-（22%）, and unknown fine particles （29%）. The sizes of these particles were mostly distributed between 0.1 and 0.4 μm. Compositions of 202 mineral particles were obtained by SEM/EDX. Mineral particles were mainly classified into three types： Si-rich, Ca-rich, and Na-rich. The compositions of typical mineral particles can indicate their sources in sampling location. For example, mineral particles, collected along the main street, were associated with trace amounts of heavy metals, such as Zn, Ti, Mn, Ba, Pb, and As. TEM observations indicate that most Na-rich particles were aged sea salt particles （e.g., Na2SO4 and NaNO3） which formed through heterogeneous chemical reactions between sea salt and acidic gases. Additionally, aging time of soot was short in Macao due to high humidity, high temperature, and high levels of sunlight in Macao. Most of soot and fine mineral dust particles were internally mixed with secondary particles.
基金supported by the National Natural Science Foundation of China (20933001,41175119 and 20873006)the National Basic Research Program of China (2009CB220100)the Trans-Century Training Program Foundation for the Talents
文摘Morphological changes with decreasing relative humidity(RH) of supersaturated sea-salt aerosol droplets on a quartz substrate were observed using a high-speed video-camera.Stable gypsum(CaSO4·2H2O) or the metastable hemihydrate(CaSO4·0.5H2O) were precipitated as the RH decreased.The dynamic process of crystal growth under steady-state humidity was studied by controlling the RH;the metastable hemihydrate was precipitated at 70.5%-77.1% RH,and the apparent crystal growth rate was between 1.42 and 2.33 μm3/s.Stable gypsum was formed at 80.7%-82.2% RH,and the apparent crystal growth rate was between 0.70 and 0.81 μm3/s.
基金Supported by the National Natural Science Foundation of China(41875168 and 41705117)Natural Science Foundation of Guangdong Province(2015A030311026)Guangzhou Science and Technology Plan(201707010088)
文摘We investigate the effects of sea-salt aerosol(SSA) activated as cloud condensation nuclei on the microphysical processes, precipitation, and thermodynamics of a tropical cyclone(TC). The Weather Research and Forecasting model coupled with Chemistry(WRF-Chem) was used together with a parameterization of SSA production. Three simulations, with different levels of SSA emission(CTL, LOW, HIGH), were conducted. The simulation results show that SSA contributes to the processes of autoconversion of cloud water and accretion of cloud water by rain,thereby promoting rain formation. The latent heat release increases with SSA emission, slightly increasing horizontal wind speeds of the TC. The presence of SSA also regulates the thermodynamic structure and precipitation of the TC.In the HIGH simulation, higher latent heat release gives rise to stronger updrafts in the TC eyewall area, leading to enhanced precipitation. In the LOW simulation, due to decreased latent heat release, the temperature in the TC eye is lower, enhancing the downdrafts in the region; and because of conservation of mass, updrafts in the eyewall also strengthen slightly; as a result, precipitation in the LOW experiment is a little higher than that in the CTL experiment.Overall, the relationship between the precipitation rate and SSA emission is nonlinear.
基金supported by the Nati onal Natural Science Foundation of China(Distinguis lbed Innovat ion Group,40071 025)Chinese Academy of Sci ences(Grant Nos.Talent Project KZCX1-10-09,KZCX3-SW-33 9)+5 种基金Diector Fund of Key Laboratory of Ice Core and Cold Regions Fnvironment,Cold and Arid Regions Environmental and Engineeni ng Research Institute,CASThe First Chinese National Arctic R es earch ExpeditionUS Nat ional Science Founda tion(ATM-0139481,ESE-9904069)the Electric Power Research Ins titutethe US Environmental Protection Agency,and Environment Canadasupport from the Arctic Institute of North America,University of Calgary,and S.Whitlow,M.Spencer and C.Buck for analyzing samples from both cores.
文摘Atmospheric circulation reconstruction based on glaciochemical records requires knowledge of chemical concentration controls, such as source, transport pathway and strength. To gain insight into these processes, the relationships between glaciochemical records from two Northern Hemisphere sites (Mt. Logan in Yukon Territory and 20D in southern Greenland) and instrumental sea level pressure (SLP) series are investigated. Calibrations between Mt. Logan sea-salt sodium (ssNa+) concentration and SLP series show that ssNa+ concentrations are closely correlated with the autumntime (SON) Aleutian Low and the summertime (JJA) North Pacific Subtropical High. Both the deepened Aleutian Low and enhanced North Pacific Sub- tropical High strengthen the transport of sea-salt aerosols from the North Pacific to the Mt. Logan region. Calibrations between 20D ssNa+ concentrations and SLP series indicate that ssNa+ concentrations are closely related to the wintertime (Jan.) Icelandic Low. A deepening of the Icelandic Low strengthens winter storms and frequent cyclogenesis over the North Atlantic and pushes more sea-salt laden air masses to the Greenland ice sheet. Therefore, ice core ssNa+ records from the Mt. Logan region can be considered as a proxy for reconstructing the au- tumntime Aleutian Low and summertime North Pacific Subtropical High, and the ssNa+ records from Greenland ice core (20D) may provide a proxy for reconstructing the wintertime Icelandic Low.
基金This study was supported by the Education Bureau of Hebei Province for Excellent Young Scholars （YQ2014020）, the Natu- ral Science Foundation of Hebei Province （D2016402120） and the National Natural Science Foundation of China （41541038）. The Chinese Scholarship Council （CSC） supported Wei Hu＇s research at the Prefectural University of Kumamoto, Japan. We thank Ms. Jin-hui Shi and Ms. Cheng-cheng Chen for their assistance with particle collection, and Nicholas James O＇Connor for his assistance with editing.
文摘Dry deposited particles, larger than 1.3 μm, were collected under clear, cloudy, and foggy conditions during a cruise, traversing the Yellow Sea and the East China Sea from 23 March to 8 April 2011. In these areas, air masses are influenced by pollution outflows from the Asian continent. The size and elemental composition of dry deposited particles were investigated using a scanning electron microscope. Number-size distributions of these particles were approximately lognormal. Under clear conditions, the mode size was about 5.0 μm, with a mean diameter of 6.9 μm. Under cloudy and foggy conditions, the mean diameters were 5.7 and 6.0 μm, respectively, but the mode sizes were vague. Non-mixed mineral particles, sea salt, and mixed mineral-sea salt particles were the major particle types. Correspondingly, Al and Si were the most frequently detected elements. Frequencies of K-, Ca-, and S-containing particles were highest under foggy conditions, while the frequency of Na-containing particles was lowest. These results indicate that fog favored sulfate production on the particles and led to the deposited mineral particles more abundant in secondary salt, suggesting the importance to consider the dependence of the comoosition of deoosited mineral narticles on weather as well as narticle size.
