Full description
Holographic imaging of snow particles at Davis Station, Summer 2018-2019 Thomas Chambers and Murray Hamilton, University of AdelaideUniversity of Adelaide instruments (Holographic Microscope and Polarsonde) were deployed at Davis Station, Antarctica from November 2018 to October 2019. These were part of a wider campaign to study clouds and precipitation over the Southern Ocean (and its boundaries).
Other precipitation instruments include: MASC, POLAR LIDAR, BASTA, RMAN, MXPol, ceilometer, MRR, Parsivel disdrometer, Pluviometer (associated with project AAS 4292), plus Snow Drift Tower, radiometers, MET observations.
This dataset includes the following:
• A version of this document with pictures to give added context
• Raw holograms (in JPEG format) sampled at approximately 1-second intervals during snowfall events on Jan 6th and Jan 8th 2019
• Raw holograms (in raw format) sampled at approximately 10-second intervals during a snowfall event on Nov 24th 2018
• Some time-stamped particle images from the preliminary manual analysis of the Jan 8th event.
• Example Matlab scripts showing how to reconstruct images from the holograms, and how to read a hologram file in raw format.
The dates of the included data have been selected to correspond with precipitation events (falling or drifting snow), as detected by one or more of the associated instruments, primarily the pluviometer (a snowfall gauge analogous to a rain gauge), the POLAR lidar and the snow particle counter. This selection was made to keep the amount of uploaded data reasonable.
The timestamps for the holograms are built into the data filenames generated by the camera. The format is “Qtcam-yy_mm_dd-hh_MM_ss” .
The camera is a See3CAM_CU51 from e-con Systems India Pvt Ltd, operated in global shutter mode to handle the 150ns laser pulse width. Its sensor has 2592 x 1944 pixels. One of the Matlab scripts shows how to read files in the camera’s raw format, which is not like other camera raw formats such as *.dng, *.pef etc.
Holographic Microscope Resolution
• Diffraction limited longitudinal resolution significantly poorer than transverse resolution
• Resolution is measured experimentally due to hard to constrain contributions from the laser spatial + temporal coherence, dynamic range of camera, camera noise etc.
• Can effectively resolve particles with sizes ranging from ~3 microns up to 3mm within a sampling volume of ~1 cubic centimetre
Lineage
Progress Code: completedData time period: 2018-11-23 to 2019-01-30
text: westlimit=74.125; southlimit=-69.73481; eastlimit=81.96875; northlimit=-67.32166
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Citation reference for this metadata record and dataset. (GET DATA > DIRECT DOWNLOAD)
uri :
https://data.aad.gov.au/eds/5696/download
Public information for AAS project AAS_4308 (PROJECT HOME PAGE)
uri :
https://projects.aad.gov.au/report_project_public.cfm?project_no=AAS_4308
Citation reference for this metadata record and dataset. (VIEW RELATED INFORMATION)
uri :
https://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=AAS_4308_Davis_Snow_Holograms
- global : AAS_4308_Davis_Snow_Holograms