Precipitation sensor MPS

Overview
This optical disdrometer measures precipitation particle size distribution, particle fall velocity and rain rate for droplets from 50 µm to greater than 6.4 mm. It is deployed in research applications (used by the National Weather Service for rain and drizzle studies).

Features and benefits

• Highly detailed measurements — 2D imaging of particle sizes and shapes plus a 1D size histogram; post-processing enables derivation of rainfall rate and intensity.
• All-weather performance — Heated optical heads prevent window fogging or icing.
• Improved functionality — Integrated wind vane aligns the sample path with the wind; free‑standing swivel mount for flexible installation.
• Lifecycle Care Program — Calibration and maintenance options available to support long‑term instrument integrity and performance.

Technology
Particle imaging

• Laser diode light is shaped into an elliptical beam to illuminate the detection volume.
• The light and the shadow of a drop are imaged onto a 64‑element photodiode array (a 50 µm drop shadows one element; a 3,200 µm drop shadows the full array).

Main applications

• Weather modification research
• Visibility and fog studies

PADS – Particle Analysis and Display System
Optional PADS software provides a virtual instrument panel to control the MPS, display real‑time data and logs, and perform post‑processing.

• Sample and record data
• View particle volume and number concentrations, Median Volume Diameter (MVD) and Effective Diameter (ED)
• View Liquid Water Content (LWC) as measured by the MPS
• Monitor instrument parameters such as laser current and electronics voltages
• Play back data for post‑mission review
• Reprocess data with new parameters for additional analysis

Accessories

• PADS software and laptop (optional)

Technical information
Measured parameters: Single‑particle light imaging
Derived parameters: Particle diameter; Particle number concentration; Liquid Water Content (LWC); Effective Diameter (ED); Median Volume Diameter (MVD)
Technique: 64‑element photodiode array, 20 cm path length
Resolution: 25, 50 or 100 µm (specify when ordering)
Particle size range: 50 µm to >6.4 mm (maximum depends on probe resolution)
Number concentration range: 0–2,000 particles/cm3
Fall velocity range: 5–500 cm/s (particle‑by‑particle)
Inter‑arrival time: 0.001–100 s
Communications: High‑speed serial RS‑422; USB
Software: Optional PADS for data display, recording and playback
Power: 115 V / 60 Hz or 230 V / 50 Hz (specify when ordering); consumption 200 W

Specifications

• Model name: MPS (Meteorological Particle Spectrometer)
• Measurement type: Precipitation optical disdrometer, single‑particle light imaging
• Particle size detection range: 50 µm to >6.4 mm
• Resolution options: 25 µm, 50 µm or 100 µm (select at order)
• Detector: 64‑element photodiode array
• Optical path length: 20 cm
• Number concentration range: 0–2,000 particles/cm3
• Fall velocity measurement: 5–500 cm/s
• Inter‑arrival time range: 0.001–100 s
• Communications: RS‑422, USB
• Optional software: PADS (control, real‑time display, logging, playback, reprocessing)
• Power requirements: 115 V/60 Hz or 230 V/50 Hz; consumption 200 W