Portable Optical Particle Spectrometer

Knowledge graph centered on Portable Optical Particle Spectrometer with 50 nodes and 153 connections. Top connected: precipitation, Colorado River, elevation gradient, spatiotemporal variability, Upper Colorado River Basin.

Method synopsis

Portable Optical Particle Spectrometer (POPS) measurements of light scattering by particles passing through a laser beam to determine particle size distributions from 140 nm to 3.4 μm diameter. Instruments operate at 1-second resolution with logarithmic size binning.

Synthesized from method descriptions across 1 paper using this protocol.

Procedure from a recent peer-reviewed implementation

Steps below were extracted from the most recent peer-reviewed implementation of this protocol in the corpus — Measurement report: An investigation of the spatiotemporal variability in aerosols in the mountainous terrain of the upper Colorado River basin using SAIL-Net (2025), Atmospheric Chemistry and Physics. Implementations in other papers (listed below) may differ.

1. Install aerosol measurement instruments
   Each site was equipped with three instruments: a Portable Optical Particle Spectrometer (POPS) for particle size distributions from 140 nm to 3.4 μm, a miniature CCN counter (CloudPuck), and a filter sampler (TRAPS) for ice-nucleating particle analysis. Instruments were mounted on 3 m tall scaffolding and enclosed in weatherproof housings with baffled inlets facing downward for weather protection.
   Quantities: 18 total instruments (3 per site across 6 sites), 3 m mounting heightDuration: Continuous operation except during power outages or instrument malfunctionsConditions: All-weather operation with instruments protected by weatherproof enclosures and elevated above winter snow levels
   Equipment: POPS instruments, CloudPuck CCN counters, TRAPS filter samplers, weatherproof enclosures, baffled inlets
2. Perform monthly site maintenance and calibration checks
   Sites were visited approximately monthly to perform instrument reliability checks, document drift, and conduct PSL checks. The PSL check involved measuring 495 nm polystyrene latex beads to assess sizing accuracy. Inlet flow was checked and accuracy of each POPS recorded. Major repairs or instrument replacements were performed as needed, with instruments returned the following month when possible.
   Quantities: Monthly visits to all 6 sites, 495 nm PSL bead size standardDuration: Several hours per site visit, monthly throughout deployment periodConditions: Accessibility sometimes limited due to weather or snow conditions

Typical Equipment

• POPS instruments
• 495 nm polystyrene latex beads

Output Measurements

• particle size distributions
• number concentrations

Papers Using This Protocol (1)

Places Where Used