2DP

• Full Name: Two-Dimensional Optical Array Precipitation Probe

• Short Name or Acronym: 2DP

• Measurements Provided: two-dimensional images of hydrometeors

• Manufacturer or Builder of the Instrument: Particle Measuring Systems, Inc.

• Operational Status:

  • requestable, ready for deployment

• General Description:

  • See the description of the 2DC probe. The 2DP only differs in that it has a larger opening between the arms to increase the sample volume for large hydrometeors and it has 200 or, recently, 100 micrometer resolution in place of the 25 micrometer resolution of the 2DC. It also is less subject to uncertainties arising from the depth-of-field for small particles because, above 200 micrometers, the depth of field exceeds the gap between the arms.

• Measurement Characteristics:

  • Overall estimate of uncertainty: For sizes above 200 micrometers, the uncertainty in concentration is approximately as determined by counting statistics, but for sizes below 200 micrometers the concentrations can be in error by as much as a factor of about 20%
  • Response time: about 2 microsecond
  • Precision:
  • Other measurement characteristics (comments on signal/noise, bias limits, etc): As for the 2DC, the recorded images can be contaminated by shattering from the arms and aperture shields. This problem is much reduced in the 2DP because more of the sample volume is far from the arms and because the fragments tend to be smaller than seen by the 2DP, but shattering can still contaminate the 2DP records.

• Lead Contact: Jorgen Jensen

Documentation

• See the documents listed for the 2DC