scholarly journals Characterizing the performance of a POPS miniaturized optical particle counter when operated on a quadcopter drone

2021 ◽  
Vol 14 (9) ◽  
pp. 6101-6118
Author(s):  
Zixia Liu ◽  
Martin Osborne ◽  
Karen Anderson ◽  
Jamie D. Shutler ◽  
Andy Wilson ◽  
...  
Keyword(s):  
Aerosol Particles ◽  
High Sensitivity ◽  
Absolute Difference ◽  
Size Distributions ◽  
Scanning Mobility Particle Sizer ◽  
Particle Counter ◽  
Wind Speeds ◽  
Optical Particle Counter ◽  
Aerosol Particle Size ◽  
The Impact

Abstract. We first validate the performance of the Portable Optical Particle Spectrometer (POPS), a small light-weight and high sensitivity optical particle counter, against a reference scanning mobility particle sizer (SMPS) for a month-long deployment in an environment dominated by biomass burning aerosols. Subsequently, we examine any biases introduced by operating the POPS on a quadcopter drone, a DJI Matrice 200 V2. We report the root mean square difference (RMSD) and mean absolute difference (MAD) in particle number concentrations (PNCs) when mounted on the UAV and operating on the ground and when hovering at 10 m. When wind speeds are low (less than 2.6 m s−1), we find only modest differences in the RMSDs and MADs of 5 % and 3 % when operating at 10 m altitude. When wind speeds are between 2.6 and 7.7 m s−1 the RMSDs and MADs increase to 26.2 % and 19.1 %, respectively, when operating at 10 m altitude. No statistical difference in PNCs was detected when operating on the UAV in either ascent or descent. We also find size distributions of aerosols in the accumulation mode (defined by diameter, d, where 0.1 ≤ d ≤ 1 µm) are relatively consistent between measurements at the surface and measurements at 10 m altitude, while differences in the coarse mode (here defined by d >  1 µm) are universally larger. Our results suggest that the impact of the UAV rotors on the POPS PNCs are small at low wind speeds, but when operating under a higher wind speed of up to 7.6 m s−1, larger discrepancies occur. In addition, it appears that the POPS measures sub-micron aerosol particles more accurately than super-micron aerosol particles when airborne on the UAV. These measurements lay the foundations for determining the magnitude of potential errors that might be introduced into measured aerosol particle size distributions and concentrations owing to the turbulence created by the rotors on the UAV.

scholarly journals Characterizing the performance of a POPS miniaturized optical particle counter when operated on a quadcopter drone

2021 ◽  
Author(s):  
Zixia Liu ◽  
Martin Osborne ◽  
Jim Haywood ◽  
Karen Anderson ◽  
Jamie D. Shulter ◽  
...  
Keyword(s):  
Wind Speed ◽  
Low Cost ◽  
Aerosol Particles ◽  
High Sensitivity ◽  
Absolute Difference ◽  
Size Distributions ◽  
Scanning Mobility Particle Sizer ◽  
Particle Counter ◽  
Optical Particle Counter ◽  
The Impact

Abstract. The Printed Optical Particle Spectrometer (POPS) is an advanced and small low-cost, light-weight, and high-sensitivity optical particle counter (OPC), particularly designed for deployed on unpiloted aerial vehicles (UAVs) and balloon sondes. We report the performance of the POPS against a reference scanning mobility particle sizer (SMPS) and an airborne passive cavity aerosol spectrometer probe (PCASP) while the POPS is operated on the ground and also while operated on a quadcopter drone, a DJI Matrice 200 V2. This is the first such documented test of the performance of a POPS instrument on a UAV. We investigate the root mean square difference (RMSD) and mean absolute difference (MAD) in particle number concentrations (PNCs) when operating on the ground and on the Matrice 200. When windspeeds are less than 2.6 m/s, we find only modest differences in the RMSDs and MADs of 2.4 % and 2.3 % respectively when operating on the ground, and to 5 % and 3 % when operating at 10m altitude. When windspeeds are greater than 2.6 m/s but less than 7.7 m/s the RMSDs and MADs increase to 10.2 % and 7.8 % respectively when operating on the ground, and 26.2 % and 19.1 %, respectively when operating at 10m altitude. No statistical difference in PNCs was detected when operating on the UAV in either ascent or descent. We also find size distributions of aerosols in the accumulation mode (here defined by diameter, d, where 0.1 ≤ d ≤ 1 µm) are relatively consistent between measurements at the surface and measurements at 10m altitude with RMSD and MAD of less than 21.6 % and 15.7 %, respectively. However, the differences between coarse mode (here defined by d > 1 µm) are universally larger than those measured at the surface with a RMSD and MAD approaching 49.5 % and 40.4 %. Our results suggest that the impact of the UAV rotors on the POPS does not unduly affect the performance of the POPS for wind speed less than 2.6 m/s, but when operating under higher wind speed of up to 7.6 m/s, larger discrepancies are noted. In addition to this, it appears that the POPS measures sub-micron aerosol particles more accurately than super-micron aerosol particles when airborne on the UAV. These measurements lay the foundations for determining the magnitude of potential errors that might be introduced into measured aerosol particle size distributions and concentrations owing to the turbulence created by the rotors on the UAV.

scholarly journals A light-driven burst of hydroxyl radicals dominates oxidation chemistry in newly activated cloud droplets

2019 ◽  
Vol 5 (5) ◽  
pp. eaav7689 ◽  
Author(s):  
Suzanne E. Paulson ◽  
Peter J. Gallimore ◽  
Xiaobi M. Kuang ◽  
Jie Rou Chen ◽  
Markus Kalberer ◽  
...  
Keyword(s):  
Hydroxyl Radicals ◽  
Uv Light ◽  
Aerosol Particles ◽  
Cloud Droplet ◽  
Radiative Properties ◽  
Size Distributions ◽  
Cloud Droplets ◽  
New Process ◽  
Oxidation Chemistry ◽  
The Impact

Aerosol particles and their interactions with clouds are one of the most uncertain aspects of the climate system. Aerosol processing by clouds contributes to this uncertainty, altering size distributions, chemical composition, and radiative properties. Many changes are limited by the availability of hydroxyl radicals in the droplets. We suggest an unrecognized potentially substantial source of OH formation in cloud droplets. During the first few minutes following cloud droplet formation, the material in aerosols produces a near-UV light–dependent burst of hydroxyl radicals, resulting in concentrations of 0.1 to 3.5 micromolar aqueous OH ([OH]aq). The source of this burst is previously unrecognized chemistry between iron(II) and peracids. The contribution of the “OH burst” to total OH in droplets varies widely, but it ranges up to a factor of 5 larger than previously known sources. Thus, this new process will substantially enhance the impact of clouds on aerosol properties.

scholarly journals The Asian tropopause aerosol layer within the 2017 monsoon anticyclone: microphysical properties derived from aircraft-borne in situ measurements

2021 ◽  
Vol 21 (19) ◽  
pp. 15259-15282
Author(s):  
Christoph Mahnke ◽  
Ralf Weigel ◽  
Francesco Cairo ◽  
Jean-Paul Vernier ◽  
Armin Afchine ◽  
...  
Keyword(s):  
Particle Size ◽  
Aerosol Particle ◽  
Aerosol Particles ◽  
Aerosol Layer ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Data Set ◽  
Microphysical Properties ◽  
Aerosol Particle Size

Abstract. The Asian summer monsoon is an effective pathway for aerosol particles and precursors from the planetary boundary layer over Central, South, and East Asia into the upper troposphere and lower stratosphere. An enhancement of aerosol particles within the Asian monsoon anticyclone (AMA), called the Asian tropopause aerosol layer (ATAL), has been observed by satellites. We discuss airborne in situ and remote sensing observations of aerosol microphysical properties conducted during the 2017 StratoClim field campaign within the AMA region. The aerosol particle measurements aboard the high-altitude research aircraft M55 Geophysica (maximum altitude reached of ∼20.5 km) were conducted with a modified ultra-high-sensitivity aerosol spectrometer – airborne (UHSAS-A; particle diameter detection range of 65 nm to 1 µm), the COndensation PArticle counting System (COPAS, detecting total concentrations of submicrometer-sized particles), and the New Ice eXpEriment – Cloud and Aerosol Spectrometer with Detection of POLarization (NIXE-CAS-DPOL). In the COPAS and UHSAS-A vertical particle mixing ratio (PMR) profiles and the size distribution profiles (for number, surface area, and volume concentration), the ATAL is evident as a distinct layer between ∼370 and 420 K potential temperature (Θ). Within the ATAL, the maximum detected PMRs (from the median profiles) were ∼700 mg−1 for particle diameters between 65 nm and 1 µm (UHSAS-A) and higher than 2500 mg−1 for diameters larger than 10 nm (COPAS). These values are up to 2 times higher than those previously found at similar altitudes in other tropical locations. The difference between the PMR profiles measured by the UHSAS-A and the COPAS indicate that the region below the ATAL at Θ levels from 350 to 370 K is influenced by the nucleation of aerosol particles (diameter <65 nm). We provide detailed analyses of the vertical distribution of the aerosol particle size distributions and the PMR and compare these with previous tropical and extratropical measurements. The backscatter ratio (BR) was calculated based on the aerosol particle size distributions measured in situ. The resulting data set was compared with the vertical profiles of the BR detected by the multiwavelength aerosol scatterometer (MAS) and an airborne miniature aerosol lidar (MAL) aboard the M55 Geophysica and by the satellite-borne Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP). The data of all four methods largely agree with one another, showing enhanced BR values in the altitude range of the ATAL (between ∼15 and 18.5 km) with a maximum at 17.5 km altitude. By means of the AMA-centered equivalent latitude calculated from meteorological reanalysis data, it is shown that such enhanced values of the BR larger than 1.1 could only be observed within the confinement of the AMA.

Peculiarities of Registration of Fungi Spores in the Air with the Help of Aerosol Particles Counters

2019 ◽  
pp. 71-79
Author(s):  
A.V. Aleksandrova ◽  
E.A. Antonov ◽  
M.I. Veselaya ◽  
V.I. Kalechits ◽  
I.E. Kovbasyuk ◽  
...  
Keyword(s):  
Aerosol Particle ◽  
Aerosol Particles ◽  
Fungal Spores ◽  
Airborne Particles ◽  
Dust Particles ◽  
Background Concentrations ◽  
Particle Counter ◽  
Suspended State ◽  
Large Size ◽  
Aerosol Particle Size

The applicability of laser aerosol particle counters for the registration of microscopic fungal spores in the airborne state (including in the presence of background concentrations of atmospheric airborne particles) was demonstrated during the experiments, and a technique was developed to transfer large (from one to several tens of microns in diameter) fungal spores to the air-suspended state, and to register them confidently with a resolution ensuring their identification. Despite the relatively large size of spores, their detection by the aerosol particle counter is possible for a period of time sufficient to track the movement of spores over significant (compared to conventional dust particles) distances. At the same time, according to the results of measurements, it is possible to judge not only the presence of spores in the air, their size, quantity and ways of movement, but also to draw some preliminary conclusions about their properties, in particular, about the tendency to glue and form aggregates. fungal spores, aerosol, particle size distribution, aerosol particle counter.

scholarly journals Freezing Drizzle Formation in Stably Stratified Layer Clouds. Part II: The Role of Giant Nuclei and Aerosol Particle Size Distribution and Solubility

2005 ◽  
Vol 62 (7) ◽  
pp. 2037-2057 ◽  
Author(s):  
István Geresdi ◽  
Roy Rasmussen
Keyword(s):  
Size Distribution ◽  
Aerosol Particle ◽  
Mesoscale Model ◽  
Cloud Condensation Nuclei ◽  
Aerosol Particles ◽  
Size Distributions ◽  
Two Dimensional ◽  
Insoluble Particles ◽  
Aerosol Particle Size ◽  
Giant Nuclei

Abstract This paper investigates how the characteristics of aerosol particles (size distribution and solubility) as well as the presence of giant nuclei affect drizzle formation in stably stratified layer clouds. A new technique was developed to simulate the evolution of water drops from wet aerosol particles and implemented into a detailed microphysical model. The detailed microphysical model was incorporated into a one-dimensional parcel model and a two-dimensional version of the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5). Sensitivity experiments were performed with the parcel model using a constant updraft speed and with the two-dimensional model by simulating flow over a bell-shaped mountain. The results showed that 1) stably stratified clouds with weak updrafts (&lt;10 cm s−1) can form drizzle relatively rapidly for maritime size distributions with any aerosol particle solubility, and for continental size distributions with highly insoluble particles due to the low number of activated cloud condensation nuclei (CCN) (&lt;100 cm−3), 2) drizzle is suppressed in stably stratified clouds with weak updrafts (&lt;10 cm s−1) for highly soluble urban and extreme urban size distributions, and 3) the presence of giant nuclei only has an effect on drizzle formation for the highly soluble continental aerosol size distributions.

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