Cloud Combination Probe

The CCP is a multipurpose particle spectrometer that includes three Droplet instruments (CDP, CIP, and LWC) – plus temperature and relative humidity sensors – in a single package. Researchers use the CCP to obtain aerosol particle and cloud hydrometeor size distributions.


Get five measurements packaged into a single canister to enable optimized measurement of cloud particles prior to and during transition to precipitation.

See data on aerosol particle and cloud hydrometeor size distributions from 2 μm to 50 μm, two dimensional images and precipitation size distributions from 25 μm to 1550 μm (or 2 μm to 930 μm if the CIP component is ordered with 15-μm resolution), and liquid water content from 0.05 g/m3 to 3 g/m3.

Get more precise information on individual particle sizes with the optional PBP feature – including particle size in digital counts, individual particle time with μsec resolution, and inter-arrival particle time (IPT).

Use the optional grayscale imaging and fine-resolution features (for the CIP) to get more clarity on particle composition.

Reduce the incidence of particle artifacts with optional Korolev anti-shatter tips (CIP feature), and keep your CIP instrument performing optimally with optional 8 VDC or 115 VAC anti-ice heaters.

Particle imaging and particle light-scattering

The three Droplet instruments included in the CCP are the Cloud Imaging Probe (CIP), the Cloud Droplet Probe (CDP), and the Hotwire Liquid Water Content Sensor (Hotwire LWC).

  • Shadow images of particles passing through a collimated laser beam are projected onto a linear array of 64 photodetectors to determine presence of particles.
  • Particle images are reconstructed from individual “slices,” where a slice is the state of the 64-element linear array at a given moment in time.


  • The CDP is a forward-scattering optical spectrometer that accepts and sizes only particles that pass through a region of the laser beam with uniform power.
  • Forward-scattered light is collected, directed through a 50/50 optical beam splitter, then measured by photodetectors to determine size and depth of field.


  • The LWC features a coiled wire that is maintained at 150 °C, which acts as variable resistance in a Wheatstone Bridge circuit.
  • The resistance of the sensing coil is directly proportional to its temperature.
  • Power dissipated by the sensor to maintain temperature is used to calculate vaporization, and in turn, liquid water content.
ParameterCIP SpecificationCDP SpecificationLWC Specification
Technique Optical Array Probe with 64 elements: 62 sizing elements, end diodes rejectLight-scattering probe with 30 size binsTemperature-Controlled Hotwire Sensor
Measured Particle Size Range 12.5 µm – 1.55 mm (standard)2 µm to 50 µmN/A; measured LWC range is 0 - 3 g/m3
Sample Area Variable; depends on tip configuration and particle size0.24 mm2N/A
Upper Concentration Range Depends on particle size, but up to 500 particles/ cm3 for a CIP with standard tips and arm width2,000 particles/cm33 g/m3
Air Speed Range 10 - 300 m/s for 25 μm resolution CIP; 10 - 180 m/s for 15 μm CIP10 - 250 m/s10 - 200 m/s
Number of Size Bins 6230N/A
Sampling Frequency 1D histogram data: 0.05 to 25 Hz 2D image data: variable interval, when buffer fillsSelectable, 0.05 to 25 HzN/A
Laser 658 nm, 30 mW658 nm, ~50 mWN/A
Non-absorbing Refractive Index N/A1.33 (the industry standard for water)N/A
Light Collection Angles N/A4° - 12°N/A
Auxiliary Parameters Ambient Temperature Relative Humidity Static Pressure Dynamic PressureN/AN/A
Data System Interface: 2D CIP data: RS-422, High Speed, 4 Mb/sec Baud Rate System data: RS-422, 56.6 kb/sec Baud Rate
Weight 29 lbs./13.2kg for probe and canister
Power Requirements System Power bus: 28 VDC, 3A Auxiliary bus (formerly “LWC bus”): 28 VDC, up to 8A (depends on LWC content) CIP Anti-Ice bus: 28 VDC, 13A CDP Anti-Ice bus:28 VDC, 7A
Environmental Operating Conditions Temperature: -40 °C to +40°C (-40 °F to +104 °F) RH: 0 – 100%, non-condensing Altitude: 0 - 50,000 ft
  • PADS software and laptop
  • Data Acquisition System

The Lifecycle Care Program ensures instrument integrity and performance vital to your research mission for 3 years or 3 calls (whichever comes first). When conducting complex and time intensive laboratory or field measurements it is critical to avoid down time, and ensure data collection accuracy. The program consists of 3 key deliverables for each year or call:

  • Instrument Logistics
  • Instrument Integrity
  • Instrument Performance

Lifecycle Care Program Includes:


  • Shipping to and from Droplet Measurement Technologies facility
  • Customs handling, including CARNET ATA if required


  • Incoming instrument evaluation and health check


  • Software and firmware validation
  • 100%-unit functionality test
  • Calibration data
  • Calibration report
  • Certificate of calibration

At times, our technician might discover an instrument issue, which might not be covered by the Lifecycle Care Program or by our product warranty. In such case we will reach out to you with a service & repair estimate to allow you to provide us with the next steps of action.