scholarly journals How weather events modify aerosol particle size distributions in the Amazon boundary layer

2021 ◽  
Vol 21 (23) ◽  
pp. 18065-18086
Author(s):  
Luiz A. T. Machado ◽  
Marco A. Franco ◽  
Leslie A. Kremper ◽  
Florian Ditas ◽  
Meinrat O. Andreae ◽  
...  
Keyword(s):  
Particle Size ◽  
Vertical Velocity ◽  
Ultrafine Particles ◽  
Rain Rate ◽  
Early Morning ◽  
Lightning Activity ◽  
Wind Profiler ◽  
Cloud Liquid Water ◽  
Weather Events ◽  
Aerosol Particle Size

Abstract. This study evaluates the effect of weather events on the aerosol particle size distribution (PSD) at the Amazon Tall Tower Observatory (ATTO). This research combines in situ measurements of PSD and remote sensing data of lightning density, brightness temperature, cloud top height, cloud liquid water, and rain rate and vertical velocity. Measurements were obtained by scanning mobility particle sizers (SMPSs), the new generation of GOES satellites (GOES-16), the SIPAM S-band radar and the LAP 3000 radar wind profiler recently installed at the ATTO-Campina site. The combined data allow exploring changes in PSD due to different meteorological processes. The average diurnal cycle shows a higher abundance of ultrafine particles (NUFP) in the early morning, which is coupled with relatively lower concentrations in Aitken (NAIT) and accumulation (NACC) mode particles. From the early morning to the middle of the afternoon, an inverse behavior is observed, where NUFP decreases and NAIT and NACC increase, reflecting a typical particle growth process. Composite figures show an increase of NUFP before, during and after lightning was detected by the satellite above ATTO. These findings strongly indicate a close relationship between vertical transport and deep convective clouds. Lightning density is connected to a large increase in NUFP, beginning approximately 100 min before the maximum lightning density and reaching peak values around 200 min later. In addition, the removal of NACC by convective transport was found. Both the increase in NUFP and the decrease in NACC appear in parallel with the increasing intensity of lightning activity. The NUFP increases exponentially with the thunderstorm intensity. In contrast, NAIT and NACC show a different behavior, decreasing from approximately 100 min before the maximum lightning activity and reaching a minimum at the time of maximum lightning activity. The effect of cloud top height, cloud liquid water and rain rate shows the same behavior, but with different patterns between seasons. The convective processes do not occur continually but are probably modulated by gravity waves in the range of 1 to 5 h, creating a complex mechanism of interaction with a succession of updrafts and downdrafts, clouds, and clear-sky situations. The radar wind profiler measured the vertical distribution of the vertical velocity. These profiles show that downdrafts are mainly located below 10 km, while aircraft observations during the ACRIDICON–CHUVA campaign had shown maximum concentrations of ultrafine particles mainly above 10 km. Our study opens new scientific questions to be evaluated in order to understand the intricate physical and chemical mechanisms involved in the production of new particles in Amazonia.

scholarly journals How weather events modify aerosol particle size distributions in the Amazon boundary layer

2021 ◽  
Author(s):  
Luiz Augusto Toledo Machado ◽  
Marco A. Franco ◽  
Leslie A. Kremper ◽  
Florian Ditas ◽  
Meinrat O. Andreae ◽  
...  
Keyword(s):  
Particle Size ◽  
Vertical Velocity ◽  
Ultrafine Particles ◽  
Rain Rate ◽  
Early Morning ◽  
Lightning Activity ◽  
Wind Profiler ◽  
Cloud Liquid Water ◽  
Weather Events ◽  
Aerosol Particle Size

Abstract. This study evaluates the effect of weather events on the aerosol particle size distribution (PSD) at the Amazon Tall Tower Observatory (ATTO). This research combines in-situ measurements of PSD and remote sensing data of lightning density, brightness temperature, cloud top height, cloud liquid water, and rain rate and vertical velocity. Measurements were obtained by a scanning mobility particle sizers (SMPS), the new generation of GOES satellites (GOES-16), the SIPAM S-band radar, and the LAP 3000 radar wind profiler recently installed at the ATTO-Campina site. The combined data allow exploring changes in PSD due to different meteorological processes. The average diurnal cycle shows a higher abundance of ultrafine particles (NUFP) in the early morning, which is coupled with lower concentrations in Aitken (NAIT) and accumulation (NACC) mode particles. From the early morning to the middle of the afternoon, an inverse behavior is observed, where NUFP decreases and NAIT and NACC increase, reflecting a typical particle growth process. Composite figures show an increase of NUFP before, during, and after lightning was detected by the satellite above ATTO. These findings strongly indicate a close relationship between vertical transport and deep convective clouds. Lightning density is connected with a large increase in NUFP, beginning approximately 100 minutes before the maximum lightning density and reaching peak values around 200 minutes later. In addition, the removal of NACC by convective transport was found. Both the increase in NUFP and the decrease in NACC appear in parallel with the increasing intensity of lightning activity. The NUFP increases exponentially with the thunderstorm intensity. In contrast, NAIT and NACC show a different behavior, decreasing from approximately 100 minutes before the maximum lightning activity and reaching a minimum at the time of maximum lightning activity. The effect of cloud top height, cloud liquid water, and rain rate shows the same behavior, but with different patterns among seasons. The convective processes do not occur continually but are modulated by gravity waves in the range of 1 to 5 hours, creating a complex mechanism of interaction with a succession of updrafts and downdrafts, clouds and clear sky situations. The radar wind profiler measured the vertical distribution of the vertical velocity. These profiles show that downdrafts are mainly located below 10 km, while aircraft observations during the ACRIDICON-CHUVA campaign had shown maximum concentrations of ultrafine particles mainly above 10 km. Our study opens new scientific questions to be evaluated in order to understand the intricate physical and chemical mechanisms involved in the production of new particles in Amazonia.

How Weather Events Modify Amazonian Surface Aerosol Particle Size Distributions

2021 ◽  
Author(s):  
Luiz A. T. Machado ◽  
Mira Pöhlker ◽  
Paulo Artaxo ◽  
Micael Cecchini ◽  
Florian Ditas ◽  
...  
Keyword(s):  
Particle Size ◽  
Vertical Distribution ◽  
Vertical Velocity ◽  
Ultrafine Particles ◽  
Wind Profile ◽  
Early Morning ◽  
Number Concentration ◽  
Rainfall Events ◽  
Weather Events ◽  
The Vertical Distribution

<p>In the last years, several studies were published evaluating aerosol-cloud-precipitation interactions. These studies improved the knowledge and reduced the uncertainties in the quantification of the aerosol aerosol-cloud interactions. However, there were only very few attempts to describe how clouds modify the aerosol properties. The main goal of this study is to evaluate the effect of weather events on the Particle Size Distribution (PSD) at the Amazon Tall Tower Observatory (ATTO). This research combines different types of datasets, all co-located at the ATTO towers. Basically, the data were obtained from the new generation of GOES satellites, GOES-16, the SIPAM S Band radar and two Scanning Mobility Particle Sizers (SMPS) installed at the heights of 60 and 325 m from 2017 to 2020. In addition, the LAP 3000 radar wind profile recently installed at the ATTO- Campina site was employed to evaluate the vertical distribution of the vertical velocity. The combination of these datasets allows to explore changes in PSD due to the different meteorological processes. The diurnal cycle shows an increase of nucleation particles and decrease in Aitken and accumulation modes during the night. The early morning is the time of minimum mass concentration. From the early morning to the middle of the afternoon, a contrary behaviour is observed, where the concentration of nucleation particles decreases and Aitken and accumulation mode increase, characterizing a typical particle growth process. In the late afternoon, when rain starts, PSD begin to have the night behaviour described above. Composite studies were computed to evaluate how the PSD evolve during rainfall events. The composite from lighting density shows a large increase in nucleation particles from around 100 minutes before the maximum lighting density, reaching maximum values nearly 200 minutes later. The nucleation particles growth rate increases exponentially with the thunderstorm intensity. Aitken and accumulation modes have a different behaviour, with decreasing number concentration from around 100 minutes before the maximum lighting activity and reaching the minimum concentration at the time of maximum lighting activity. This effect could be related to the more intense downdraft in thunderstorms that intensify the transport of ultrafine particles from the upper atmosphere as described in recent studies using GoAmazon and ACRIDICON-CHUVA data. Another possibility could be the transport of O<sub>3</sub> and NO<sub>2</sub> column densities during thunderstorms events, helping the oxidation of volatile organic component forming secondary organic aerosol at the surface. This is an open question and needs further studies specifically designed to understand the chemical processes occurring near-surface during intense rainfall events. The first data from the radar wind profile installed at the ATTO-Campina site was employed to compute the vertical distribution of the vertical velocity. The downdrafts are mainly located below 10km, but the layer of maximum concentration of ultrafine particles is mainly above 10km. In addition, the number concentration of nucleation particles at 60m is around twice the value at 325 m, in contrast to former studies showing an increase in ultrafine particles with height. CAFE-Brazil, scheduled for 2022, will be an opportunity to study these open questions.</p>

scholarly journals Aerosol particle size distributions in the lower Fraser Valley: evidence for particle nucleation and growth

2004 ◽  
Vol 4 (2) ◽  
pp. 1623-1663 ◽  
Author(s):  
M. Mozurkewich ◽  
T.-W. Chan ◽  
Y.-A. Aklilu ◽  
B. Verheggen
Keyword(s):  
Particle Size ◽  
Ultrafine Particles ◽  
Photochemical Oxidation ◽  
Particle Nucleation ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Hygroscopic Properties ◽  
Lower Fraser Valley ◽  
Aerosol Particle Size ◽  
Fraser Valley

Abstract. Particle size distributions from 9 to 640 nm diameter were measured at Eagle Ridge in the lower Fraser Valley from 13 August to 1 September 2001 as part of the Pacific 2001 Air Quality Study. The site was on top of a ridge, about 300 m above the valley floor, in a predominantly agricultural area about 70 km ESE of Vancouver. To further characterize the particles, their hygroscopic properties (affinity for water) were measured. The maximum of the number distributions was generally between 40 and 100 nm diameter, but the number distribution was sometimes dominated by ultrafine particles with diameters below 20 nm. These ultrafine particles, which appeared to some extent on all days, were frequently associated with elevated levels of CO and NOx, as expected for fresh vehicular emissions. The appearance of these fresh emissions was most pronounced when the growing mixed layer reached the altitude of the site. In contrast, pronounced nucleation events occurred on the five cleanest days; these resulted in particle number concentrations as high as 5×104 particles cm−3 and growth rates of 5 to 10 nm hr−1. These events appear to have been driven by the photochemical oxidation of biogenic organic compounds and to have been triggered when the UV flux reached about 25 W m−2. Dramatic growth events were also observed on the afternoons of the more polluted days; these produced an extremely narrow mode (σ<0.3) at a diameter of about 40 nm. Rainy days showed low number concentrations with the size distributions shifted to small sizes. On one of these days there was evidence of nucleation not far from the site; this may have been occurring in the vicinity of the clouds.

scholarly journals Aerosol particle size distributions in the lower Fraser Valley: evidence for particle nucleation and growth

2004 ◽  
Vol 4 (4) ◽  
pp. 1047-1062 ◽  
Author(s):  
M. Mozurkewich ◽  
T.-W. Chan ◽  
Y.-A. Aklilu ◽  
B. Verheggen
Keyword(s):  
Particle Size ◽  
Ultrafine Particles ◽  
Photochemical Oxidation ◽  
Particle Nucleation ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Hygroscopic Properties ◽  
Lower Fraser Valley ◽  
Aerosol Particle Size ◽  
Fraser Valley

Abstract. Particle size distributions from 9 to 640nm diameter were measured at Eagle Ridge in the lower Fraser Valley from 13 August to 1 September 2001 as part of the Pacific 2001 Air Quality Study. The site was on top of a ridge, about 300m above the valley floor, in a predominantly agricultural area about 70km ESE of Vancouver. To further characterize the particles, their hygroscopic properties (affinity for water) were measured. The maximum of the number distributions was generally between 40 and 100nm diameter, but the number distribution was sometimes dominated by ultrafine particles with diameters below 40nm. These ultrafine particles, which appeared to some extent on all days, were frequently associated with elevated levels of CO and NOx, as expected for fresh vehicular emissions. The appearance of these fresh emissions was most pronounced when the growing mixed layer reached the altitude of the site. In contrast, pronounced nucleation events occurred on the five cleanest days; these resulted in particle number concentrations as high as 5x104 particles cm-3 and growth rates of 5 to 10nmhr-1. Nucleation appears to have been triggered when the UV flux reached about 25Wm-2. The growth of these newly formed particles was probably driven by the photochemical oxidation of biogenic organic compounds. Dramatic growth events were also observed on the afternoons of the more polluted days; these produced an extremely narrow mode σ<0.3) at a diameter of about 40nm. Rainy days showed low number concentrations with the size distributions shifted to small sizes. On one of these days there was evidence of nucleation not far from the site; this may have been occurring in the vicinity of the clouds.

scholarly journals Analysis of Raindrop Size Distribution Characteristics in Permafrost Regions of the Qinghai–Tibet Plateau Based on New Quality Control Scheme

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2265 ◽  
Author(s):  
Ma ◽  
Zhao ◽  
Yang ◽  
Xiao ◽  
Zhang ◽  
...  
Keyword(s):  
Particle Size ◽  
Quality Control ◽  
Rain Rate ◽  
Tibet Plateau ◽  
Frozen Ground ◽  
Fall Velocity ◽  
Raindrop Size Distribution ◽  
Raindrop Size ◽  
Qinghai Tibet Plateau ◽  
Permafrost Regions

Raindrop size distribution (DSD) can reflect the fundamental microphysics of precipitation and provide an accurate estimation of its amount and characteristics; however, there are few observations and investigations of DSD in cold, mountainous regions. We used the second-generation particle size and velocity disdrometer Parsivel2 to establish a quality control scheme for raindrop spectral data obtained for the Qinghai–Tibet Plateau in 2015. This scheme included the elimination of particles in the lowest two size classes, particles >10 mm in diameter and rain rates <0.01 mm∙h−1. We analyzed the DSD characteristics for different types of precipitation and rain rates in both permafrost regions and regions with seasonally frozen ground. The precipitation in the permafrost regions during the summer were mainly solid with a large particle size and slow fall velocity, whereas the precipitation in the regions with seasonally frozen ground were mainly liquid. The DSD of snow had a broader drop spectrum, the largest particle size, the slowest fall velocity, and the largest number of particles, followed by hail. Rain and sleet shared similar DSD characteristics, with a smaller particle size, slower velocity, and smaller number of particles. The particle concentration for different classes of rain rate decreased with an increase in particle size and decreased gradually with an increase in rain rate. Precipitation with a rain rate >2 mm∙h−1 was the main contributor to the annual precipitation. The dewpoint thresholds for snow and rain in permafrost regions were 0 and 1.5 °C, respectively. The dewpoint range 0–1.5 °C was characterized by mixed precipitation with a large proportion of hail. This study provides valuable DSD information on the Qinghai–Tibet Plateau and can be used as an important reference for the quality control of raindrop spectral data in regions dominated by solid precipitation.

The Research Possibility of Definition Mass Biological Nanoobjects Using Terahertz Laser Ablation Method

2009 ◽  
Vol 4 (3) ◽  
pp. 74-77
Author(s):  
Mikhail Vagin ◽  
Anton Unitsyn ◽  
Aleksandr Petrov ◽  
Aleksandr Kozlov ◽  
Sergey Malyshkin ◽  
...  
Keyword(s):  
Particle Size ◽  
Laser Ablation ◽  
Molecular Mass ◽  
Aerosol Particle ◽  
Free Electron ◽  
Free Electron Laser ◽  
Thz Radiation ◽  
Laser Ablation Method ◽  
Aerosol Particle Size ◽  
Mass Definition

Possibility of mass definition using terahertz laser ablation method for biological nanoobjects is researched. Diffusion spectrometer of aerosols was applied for measuring the size of dispersed products of terahertz laser ablation. Dependence of molecular mass from the aerosol particle size was obtained for fragments of DNA λ-hind. This work was carried out using THz radiation of free electron laser of Siberian center of photochemical researches.

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