6533b7d3fe1ef96bd125fe85
RESEARCH PRODUCT
Application Of Microholography for Ground-based In Situ Measurements in Stratus Cloud Layers: A Case Study
Ruprecht JaenickeStephan Borrmannsubject
Atmospheric Sciencebusiness.industryAirflowHolographyOcean EngineeringWind speedAerosollaw.inventionFraunhofer linessymbols.namesakeOpticslawObservatoryParticle-size distributionsymbolsbusinessGeologyGraupelRemote sensingdescription
Abstract A holographic droplet and aerosol recording system (HODAR) has been designed and operated in situ in a low-level stratus cloud layer adopting the Fraunhofer in-line technique to measure sizes and velocity vectors of cloud droplets as well as to determine sizes and shapes of other hydrometeors (e.g., graupel). The particle-size radii covered by this ground-based instrument range from three to several hundred micrometers. A case study conducted on the Kleiner Feldberg Mountain Observatory near Frankfurt, Germany, during November 1990 documents the temporal evolution of the cloud-droplet size distribution over a period of 19 h during which the size distribution changed from monomodal to bimodal. The velocity vectors of individual droplets, assessed by means of a double pulsed hologram, can be used to prove that the apparatus does not distort the airflow at wind speeds smaller than 1 m s−1. During a different event holographic images of biogenic particles and graupel grains were recorded to demonstra...
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1993-06-01 | Journal of Atmospheric and Oceanic Technology |