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Title: Multi-Angle Snowflake Camera Instrument Handbook

Abstract

The Multi-Angle Snowflake Camera (MASC) takes 9- to 37-micron resolution stereographic photographs of free-falling hydrometers from three angles, while simultaneously measuring their fall speed. Information about hydrometeor size, shape orientation, and aspect ratio is derived from MASC photographs. The instrument consists of three commercial cameras separated by angles of 36º. Each camera field of view is aligned to have a common single focus point about 10 cm distant from the cameras. Two near-infrared emitter pairs are aligned with the camera’s field of view within a 10-angular ring and detect hydrometeor passage, with the lower emitters configured to trigger the MASC cameras. The sensitive IR motion sensors are designed to filter out slow variations in ambient light. Fall speed is derived from successive triggers along the fall path. The camera exposure times are extremely short, in the range of 1/25,000th of a second, enabling the MASC to capture snowflake sizes ranging from 30 micrometers to 3 cm.

Authors:
 [1];  [1]
  1. Univ. of Alaska, Fairbanks, AK (United States)
Publication Date:
Research Org.:
DOE Office of Science Atmospheric Radiation Measurement (ARM) Program (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER)
OSTI Identifier:
1261185
Report Number(s):
DOE/SC-ARM-TR-158
DOE Contract Number:  
AC05-7601830
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION; Snowflakes; North Slope of Alaska; hydrometeors; fall speed

Citation Formats

Stuefer, Martin, and Bailey, J. Multi-Angle Snowflake Camera Instrument Handbook. United States: N. p., 2016. Web. doi:10.2172/1261185.
Stuefer, Martin, & Bailey, J. Multi-Angle Snowflake Camera Instrument Handbook. United States. https://doi.org/10.2172/1261185
Stuefer, Martin, and Bailey, J. 2016. "Multi-Angle Snowflake Camera Instrument Handbook". United States. https://doi.org/10.2172/1261185. https://www.osti.gov/servlets/purl/1261185.
@article{osti_1261185,
title = {Multi-Angle Snowflake Camera Instrument Handbook},
author = {Stuefer, Martin and Bailey, J.},
abstractNote = {The Multi-Angle Snowflake Camera (MASC) takes 9- to 37-micron resolution stereographic photographs of free-falling hydrometers from three angles, while simultaneously measuring their fall speed. Information about hydrometeor size, shape orientation, and aspect ratio is derived from MASC photographs. The instrument consists of three commercial cameras separated by angles of 36º. Each camera field of view is aligned to have a common single focus point about 10 cm distant from the cameras. Two near-infrared emitter pairs are aligned with the camera’s field of view within a 10-angular ring and detect hydrometeor passage, with the lower emitters configured to trigger the MASC cameras. The sensitive IR motion sensors are designed to filter out slow variations in ambient light. Fall speed is derived from successive triggers along the fall path. The camera exposure times are extremely short, in the range of 1/25,000th of a second, enabling the MASC to capture snowflake sizes ranging from 30 micrometers to 3 cm.},
doi = {10.2172/1261185},
url = {https://www.osti.gov/biblio/1261185}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2016},
month = {7}
}