Multi-Angle Snowflake Camera Value-Added Product

Shkurko, Konstantin; Garrett, Timothy J.; Gaustad, Krista

doi:10.2172/1342901

Cited by 7 publications

(13 citation statements)

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“…Although the MASC processing algorithm was originally written in MATLAB, a version written in Python also exists and it is this version of the ellipse fitting method that will be analyzed here (Shkurko et al, 2016). To simplify matching particles between the three cameras, MASC only processes images that contain a single precipitation particle and, of these, only particles that are in focus are actually analyzed.…”

Section: Precipitation Imaging Package (Pip)mentioning

confidence: 99%

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Comment on amt-2021-427

2022

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Section: Precipitation Imaging Package (Pip)mentioning

confidence: 99%

“…Our emulation of the MASC processing algorithm is based on the algorithm used for the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) program MASC instruments (Stuefer and Bailey, 2016;Shkurko et al, 2016).…”

Section: Masc Emulationmentioning

confidence: 99%

Comment on amt-2021-427

2022

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“…As a particle falls through the instrument collection aperture, two vertically spaced infrared detectors simultaneously trigger the cameras to take three simultaneous photographs of the particle from the side and to measure the fallspeed between the two detectors. The MASC software processes the imagery to calculate the surface area, geometric cross-section, perimeter, orientation, aspect ratio, complexity, flatness, and whether the particle is a raindrop (Shkurko et al, 2016). Images taken by the Multi-Angle Snowflake Camera (MASC) are used in conjunction with the DEID to confirm precipitation type and refine density measurements.…”

Section: Hydrometeor Photographymentioning

confidence: 99%

Measurement report: Mass and Density of Individual Frozen Hydrometeors

Rees

Singh²,

Pardyjak³

et al. 2021

Preprint

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Abstract. A new precipitation sensor, the Differential Emissivity Imaging Disdrometer (DEID), is used to provide the first continuous measurements of the mass, diameter, and density of individual hydrometeors. The DEID consists of an infrared camera pointed at a heated aluminum plate. It exploits the contrasting thermal emissivity of water and metal to determine individual particle mass by assuming that energy is conserved during the transfer of heat from the plate to the particle during evaporation. Particle density is determined from a combination of particle mass and morphology. A Multi-Angle Snowflake Camera (MASC) was deployed alongside the DEID to provide refined imagery of particle size and shape. Broad consistency is found between derived mass-diameter and density-diameter relationships and those obtained in prior studies. However, DEID measurements show a generally weaker dependence with size for hydrometeor density and a stronger dependence for aggregate snowflake mass.

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“…Processing of MASC imagery consists of distinguishing foreground pixels from background to define the region of interest (ROI) and then fitting the ROI with a bounding ellipse(Shkurko et al, 2018). The ellipse's major axis is defined as the maximum dimension D max for each image.…”

mentioning

confidence: 99%

“…Raw data and images were processed with a local University of Utah processing suite called mascpy (The Hive: University of Utah Research Data Repository, 2020a, b), similar to that described in Shkurko et al (2018).To complement MASC observations and characterize the influence of ambient wind speed on MASC measurements, surface wind measurements from a traditional meteorological ground suite(Ritsche, 2011; ARM Climate Research Facility, 2013) 155 were matched to MASC hydrometeors by calculating a mean wind speed for the 1 minute period leading up to the observation time corresponding to each hydrometeor. In addition to the quality control checks listed inShkurko et al (2018), a surface (a) The MASC was relocated to ground level and placed inside a Belfort double Alter shield on 22 August 2016 (field site photograph courtesy of Martin Stuefer). (b) The shield consists of inner and outer fences with diameters of 1.22 m and 2.44 m, respectively.…”

mentioning

confidence: 99%

Numerical simulations and Arctic observations of surface wind effects on Multi-Angle Snowflake Camera measurements

Fitch¹,

Hang²,

Talaei³

et al. 2020

Preprint

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Abstract. Ground-based measurements of frozen precipitation are heavily influenced by interactions of surface winds with gauge-shield geometry. The Multi-Angle Snowflake Camera (MASC), which photographs hydrometeors in free-fall from three different angles while simultaneously measuring their fall speed, has been used in the field at multiple mid-latitude and polar locations both with and without wind shielding. Here we show results of computational fluid dynamics (CFD) simulations of the airflow and corresponding particle trajectories around the unshielded MASC and compare these results to Arctic field observations with and without a Belfort double Alter shield. Simulations in the absence of a wind shield show a separation of flow at the upstream side of the instrument, with an upward velocity component just above the aperture, which decreases the mean particle fall speed by 55 % (74 %) for a wind speed of 5 m s−1 (10 m s−1). MASC-measured fall speeds compare well with Ka-band Atmospheric Radiation Measurement (ARM) Zenith Radar (KAZR) mean Doppler velocities only when winds are light (< 5 m s−1) and the MASC is shielded. MASC-measured fall speeds that do not match KAZR measured velocities tend to fall below a threshold value that increases approximately linearly with wind speed but is generally

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Multi-Angle Snowflake Camera Value-Added Product

Cited by 7 publications

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Comment on amt-2021-427

Comment on amt-2021-427

Measurement report: Mass and Density of Individual Frozen Hydrometeors

Numerical simulations and Arctic observations of surface wind effects on Multi-Angle Snowflake Camera measurements

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