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OTT Parsivel² - Laser Weather Sensor

Laser precipitation disdrometer measuring all precipitation types

The OTT Parsivel² is a modern laser disdrometer for comprehensive measurement of all precipitation types. The Parsivel² captures both the size and speed of falling particles, classifying them into one of 32 separate size and velocity classes. The raw data are used to calculate the type, amount, intensity and kinetic energy of the precipitation, the visibility in the precipitation, and the equivalent radar reflectivity

  • Precipitation type, intensity, drop size distribution, radar reflectivity
  • Laser (optical)
  • Simultaneous measurement of 32 classes for particle sizes and velocities
  • SDI-12 / RS-485, pulse
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  • Accurate – the exact size and speed of every precipitation particle that passes in the measurement area is recorded and from these measurements all relevant meteorological parameters are derived
  • Maintenance-free –  no moving parts or a collection bucket, unlike tipping bucket rain gauges
  • Durable – continuous and precise precipitation data in all environmental conditions with integrated overvoltage protection
  • Energy-efficient – economical electronics and galvanically separate, controllable head heating, providing a power supply that is flexibly designed with minimal power consumption
  • Easy-to-use – integrated USB port configuration and online monitoring for simple PC data review with OTT ASDO user software
  • Precipitation Measurement: complete precipitation measurement including particle size, volume, and intensity. Precipitation size and type are each calculated into one of 32 classes, as specified by the World Meteorological Organization (WMO)
  • Monitoring Road Conditions: precipitation amount and composition are combined with general visibility measurements to provide an accurate picture of road conditions
  • Early Flood Warning: when combined with water level sensors, the Parsivel2 is the central component in an early flood warning system
  • Erosion Modeling: kinetic precipitation energy calculated by the Parsivel2, paired with other parameters like ground state or relief, provides a key input for erosion models
Road Weather Maintenance Checklist
Road Weather Maintenance Checklist
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Device Laser-optical disdrometer
Optical sensor, laser diode
Wavelength 650 nm
Output power (peak) 0.2 mW
Laser Class 1 (IEC/EN 60825-1:2014)
Measuring surface (W x D) 180 x 30 mm (54 cm²), detection of border events
Measuring ranges
Particle size Liquid precipitation: 0.2 ... 8 mm
Solid precipitation: 0.2 ... 25 mm
Particle velocity 0.2 ... 20 m/s
Size and velocity classes 32
Measurement accuracy ± 1 size class ( 0.2 ... 2 mm)
± 0.5 size class ( > 2 mm)
Types of precipitation
Number 8
Types Drizzle, drizzle/rain, rain, mixed rain/snow, snow, snow grains, sleet, hail
Reports WMO 4680/4677 (SYNOP),
4678 (METAR/SPECI) and NWS tables
Differentiation of precipitation types Drizzle, rain, hail, snow > 97 %
(compared to a weather observer)
Snow depth intensity Volume equivalent
Intensity and accuracy
Precipitation intensity 0.001 ... 1,200 mm/h
Accuracy ±5 % (liquid) /± 20 % (solid)
Radar reflectivity Z -9.999 ... 99.999 dBz
Kinetic energy 0 ... 999.999 J/(m²h)
Visibility in precipitation (MOR) 0 ... 20,000 m
De-icing protection Microprocessor controlled heating
Electrical data
Power supply electronics 10 ... 28 V DC, reverse polarity protection
Sensor head heating system Optimum heating output can be guaranteed with a power supply voltage of at least 20 V DC
Power consumption (without heating) 65 mA @ 24 V DC
Heating capacity sensor heads 50 W (default)
100 W (adjustable)
Lightning protection Integrated
Interfaces (configurable)
RS-485 For all values incl. spectral data
(EIA-485; 1,200 ... 57,600 Baud)
SDI-12 For calculated values
Ausgaberelais For pulse output of the precipitation amount in 0.1 mm/pulse
with max. 2 Hz pulse rate
USB For PC connection (configuration and service)
Mechanical data
Material Powder-coated aluminium housing
Weight Max. 6.4 kg
Dimensions (H x W x D) 670 x 600 x 114 mm
Installation 2 inch pipe, Ø 50 ... 62 mm
Environmental conditions
Temperature range -40 ... +70 °C
Relative humidity 0 ... 100 %
Protection IP65, resistant to salt spray
Standards EN 61326-1: 2013, CE compliant
2014/30/EU, CE compliant
ASDO configuration software supplied (basic version)
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